0000899866-21-000014 | 10-K | XBRL Viewer | Alexion Pharmaceuticals INC

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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2020	Feb. 04, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	0-27756
Entity Registrant Name	ALEXION PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3648318
Entity Address, Address Line One	121 Seaport Boulevard
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02210
City Area Code	475
Local Phone Number	230-2596
Title of 12(b) Security	Common Stock $0.0001 par value
Trading Symbol	ALXN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 23,569,192,552
Entity Common Stock, Shares Outstanding		219,711,754
Documents Incorporated by Reference	The contents of the amendment to this Annual Report on Form 10-K, which will be filed with the Commission within 120 days of the end of the fiscal year ended December 31, 2020, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0000899866
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 2,964.5	$ 2,685.5
Marketable securities	34.9	64.0
Trade accounts receivable, net	1,409.3	1,243.2
Inventories	775.7	627.6
Prepaid expenses and other current assets	648.6	456.1
Total current assets	5,833.0	5,076.4
Property, plant and equipment, net	1,238.8	1,163.3
Intangible assets, net	3,002.4	3,344.3
Goodwill	5,100.1	5,037.4
Right of use operating assets	223.1	204.0
Deferred tax assets	2,199.4	2,290.2
Other assets	506.2	429.0
Total assets	18,103.0	17,544.6
Current Liabilities:
Accounts payable	118.6	74.0
Accrued expenses	1,084.7	892.7
Current portion of long-term debt	142.4	126.7
Current portion of contingent consideration	114.9	0.0
Other current liabilities	164.1	100.9
Total current liabilities	1,624.7	1,194.3
Long-term debt, less current portion	2,419.6	2,375.0
Contingent consideration	299.4	192.4
Deferred tax liabilities	1,632.2	2,081.4
Noncurrent operating lease liabilities	177.1	164.1
Other liabilities	298.8	265.6
Total liabilities	6,451.8	6,272.8
Commitments and contingencies (Note 11)
Stockholders’ Equity:
Common stock, $.0001 par value; 290.0 shares authorized; 240.9 and 237.8 shares issued at 2020 and 2019, respectively	0.0	0.0
Additional paid-in capital	9,152.9	8,804.7
Treasury stock, at cost, 21.4 and 16.5 shares at 2020 and 2019, respectively	(2,620.3)	(2,105.9)
Accumulated other comprehensive loss	(124.6)	(66.8)
Retained earnings	5,243.2	4,639.8
Total stockholders’ equity	11,651.2	11,271.8
Total liabilities and stockholders’ equity	$ 18,103.0	$ 17,544.6

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	290.0	290.0
Common stock, shares issued	240.9	237.8
Treasury Stock, Shares	21.4	16.5

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total revenues	$ 6,069.9	$ 4,991.1	$ 4,131.2
Costs and expenses:
Cost of sales (exclusive of amortization of purchased intangible assets)	553.5	394.5	374.3
Research and development	1,002.9	886.0	730.4
Selling, general and administrative	1,399.9	1,261.1	1,111.8
Acquired in-process research and development	0.0	(4.1)	1,183.0
Amortization of purchased intangible assets	253.7	309.6	320.1
Change in fair value of contingent consideration	61.2	11.6	116.5
Acquisition-related costs	117.6	0.0	0.0
Restructuring expenses	10.3	12.0	25.5
Impairment of intangible assets	2,053.3	0.0	0.0
Gain on sale of asset	(14.8)	0.0	0.0
Total costs and expenses	5,437.6	2,870.7	3,861.6
Operating income	632.3	2,120.4	269.6
Other income and expense:
Investment income, net	44.7	100.3	65.3
Interest expense	(104.7)	(77.8)	(98.2)
Other income and (expense)	(3.3)	35.9	5.5
Income before income taxes	569.0	2,178.8	242.2
Income tax (benefit) expense	(34.4)	(225.5)	164.6
Net income	$ 603.4	$ 2,404.3	$ 77.6
Earnings per common share
Basic (in dollars per share)	$ 2.74	$ 10.77	$ 0.35
Diluted (in dollars per share)	$ 2.72	$ 10.70	$ 0.35
Shares used in computing earnings per common share
Basic (in shares)	220.1	223.2	222.7
Diluted (in shares)	222.0	224.8	224.5
Net Product Sales
Total revenues	$ 6,069.1	$ 4,990.0	$ 4,130.1
Other revenue
Total revenues	$ 0.8	$ 1.1	$ 1.1

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 603.4	$ 2,404.3	$ 77.6
Foreign currency translation	5.7	(1.0)	(0.5)
Unrealized gains (losses) on debt securities	0.1	0.2	(0.5)
Unrealized (losses) gains on pension obligation	(1.0)	(6.6)	2.2
Unrealized (losses) gains on hedging activities, net of tax (benefit) expense of $(18.8), $(14.5) and $7.3, respectively	(62.6)	(49.7)	23.5
Other comprehensive (loss) income, net of tax	(57.8)	(57.1)	24.7
Comprehensive income	$ 545.6	$ 2,347.2	$ 102.3

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Consolidated Statement of Comprehensive Income (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Tax on unrealized (losses) gains on hedging activities	$ (18.8)	$ (14.5)	$ 7.3

Statement of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Treasury Stock at Cost	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting standards	$ 6.1					$ 6.1
Balances, common shares at Dec. 31, 2017		234.3
Balances, value at Dec. 31, 2017	8,893.1	$ 0.0	$ 8,290.3	$ (1,604.9)	$ (34.4)	2,242.1
Balances, treasury shares at Dec. 31, 2017				12.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock, shares				0.7
Repurchase of common stock	(85.0)			$ (85.0)
Issuance of common stock under stock option and stock purchase plans, shares		0.6
Issuance of common stock under stock option and stock purchase plans	47.6		47.6
Issuance of restricted common stock, shares		1.3
Issuance of restricted common stock	(0.3)		(0.3)
Share-based compensation expense	201.5		201.5
Net income	77.6					77.6
Other comprehensive income (loss)	24.7				24.7
Balances, common shares at Dec. 31, 2018		236.2
Balances, value at Dec. 31, 2018	9,165.3	$ 0.0	8,539.1	$ (1,689.9)	(9.7)	2,325.8
Balances, treasury shares at Dec. 31, 2018				12.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting standards	$ (90.3)					(90.3)
Repurchase of common stock, shares	3.8			3.8
Repurchase of common stock	$ (416.0)			$ (416.0)
Issuance of common stock under stock option and stock purchase plans, shares		0.4
Issuance of common stock under stock option and stock purchase plans	29.9		29.9
Issuance of restricted common stock, shares		1.2
Share-based compensation expense	235.7		235.7
Net income	2,404.3					2,404.3
Other comprehensive income (loss)	(57.1)				(57.1)
Balances, common shares at Dec. 31, 2019		237.8
Balances, value at Dec. 31, 2019	$ 11,271.8	$ 0.0	8,804.7	$ (2,105.9)	(66.8)	4,639.8
Balances, treasury shares at Dec. 31, 2019	16.5			16.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock, shares	4.9			4.9
Repurchase of common stock	$ (510.8)			$ (510.8)
Issuance of common stock under stock option and stock purchase plans, shares	0.7	0.9
Issuance of common stock under stock option and stock purchase plans	$ 60.2		60.2
Issuance of restricted common stock, shares		2.2
Share-based compensation expense	277.2		280.8	(3.6)
Net income	603.4					603.4
Other comprehensive income (loss)	(57.8)				(57.8)
Portola replacement equity awards attributable to the pre-combination period	7.2		7.2
Balances, common shares at Dec. 31, 2020		240.9
Balances, value at Dec. 31, 2020	$ 11,651.2	$ 0.0	$ 9,152.9	$ (2,620.3)	$ (124.6)	$ 5,243.2
Balances, treasury shares at Dec. 31, 2020	21.4			21.4

Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
Statement of Cash Flows - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 603.4	$ 2,404.3	$ 77.6
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	329.4	376.8	405.3
Impairment of intangible assets	2,053.3	0.0	13.5
Change in fair value of contingent consideration	61.2	11.6	116.5
Payments of contingent consideration	0.0	(100.0)	0.0
Share-based compensation expense	281.1	237.0	203.0
Non-cash expense for acquired IPR&D	0.0	0.0	64.6
Deferred tax (benefit) expense	(283.4)	(455.4)	32.9
Unrealized foreign currency (gain) loss	(5.2)	(2.1)	4.8
Unrealized loss (gain) on forward contracts	6.4	(16.5)	(15.8)
Unrealized loss (gain) on strategic equity investments	3.0	(26.9)	(40.2)
Gain on sale of strategic equity investments	0.0	(32.8)	0.0
Gain on sale of asset	(14.8)	0.0	0.0
Gain on modification of purchase option	0.0	(32.0)	0.0
Gain on derecognition of Portola strategic equity investment	(29.7)	0.0	0.0
Inventory obsolescence charge	27.5	3.3	20.5
Other	4.5	(2.7)	(2.0)
Changes in operating assets and liabilities, excluding the effect of acquisitions:
Accounts receivable	(139.4)	(319.2)	(208.8)
Inventories	95.0	(160.2)	(35.2)
Prepaid expenses, right of use operating assets and other assets	(111.9)	(31.0)	(155.6)
Accounts payable, accrued expenses, lease liabilities and other liabilities	122.5	230.7	(55.1)
Net cash provided by operating activities	3,002.9	2,084.9	426.0
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(19.4)	(80.2)	(782.7)
Proceeds from maturity or sale of available-for-sale debt securities	184.2	222.2	1,473.5
Purchases of mutual funds related to nonqualified deferred compensation plan	(19.7)	(17.6)	(12.1)
Proceeds from sale of mutual funds related to nonqualified deferred compensation plan	12.1	14.7	12.3
Purchases of property, plant and equipment	(106.7)	(154.7)	(213.0)
Payments for acquisitions of businesses, net of cash and restricted cash acquired	(2,111.9)	0.0	0.0
Purchases of strategic equity investments and options	(38.1)	(73.3)	(10.3)
Proceeds from sale of strategic equity investments	0.0	114.7	0.0
Purchases of intangible assets	0.0	(16.0)	0.0
Other	0.0	(0.1)	2.8
Net cash (used in) provided by investing activities	(2,099.5)	9.7	470.5
Cash flows from financing activities:
Proceeds from revolving credit facility	0.0	0.0	250.0
Payments on revolving credit facility	0.0	(250.0)	0.0
Payments on term loan	(130.6)	(98.0)	(293.8)
Repurchase of common stock	(510.8)	(416.0)	(85.0)
Net proceeds from issuance of stock under share-based compensation arrangements	58.7	29.9	47.3
Other	(29.2)	(5.0)	(20.9)
Net cash used in financing activities	(611.9)	(739.1)	(102.4)
Effect of exchange rate changes on cash and cash equivalents and restricted cash	19.5	0.8	(11.2)
Net change in cash and cash equivalents and restricted cash	311.0	1,356.3	782.9
Cash and cash equivalents and restricted cash at beginning of period	2,723.6	1,367.3	584.4
Cash and cash equivalents and restricted cash at end of period	3,034.6	2,723.6	1,367.3
Supplemental cash flow disclosures:
Cash paid for interest (net of amounts capitalized)	99.9	72.6	90.9
Cash paid for income taxes	248.9	187.9	163.9
Supplemental non-cash disclosures from investing and financing activities:
Fair value of strategic investment and purchase option acquired, less upfront cash paid	0.0	75.0	0.0
Operating ROU lease assets obtained in exchange for operating lease liabilities	31.6	27.5	0.0
Capitalization of construction costs related to facility lease obligations	0.0	0.0	44.8
Accounts payable and accrued expenses for purchases of property, plant and equipment and intangible assets	14.9	13.3	21.4
Contingent consideration issued in acquisition	155.0	0.0	0.0
Fair value of equity shares in Portola settled at closing of the acquisition	47.8	0.0	0.0
Fair value of replacement equity awards issued to Portola employees attributable to the pre-combination period	7.2	0.0	0.0
Exchange of intellectual property rights for equity shares in Inozyme	14.8	0.0	0.0
Cash and cash equivalents	2,964.5	2,685.5	1,365.5
Restricted cash included in other current assets	70.0	37.8	0.1
Restricted cash included in other noncurrent assets	$ 0.1	$ 0.3	$ 1.7

Business Overview and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Business Overview and Summary of Significant Accounting Policies [Abstract]

Business Overview and Summary of Significant Accounting Policies

Business

Alexion Pharmaceuticals, Inc. (Alexion, the Company, we, our or us) is a global biopharmaceutical company focused on serving patients and families affected by rare diseases and devastating conditions through the discovery, development and commercialization of life-changing medicines.

As a leader in rare diseases for more than 25 years, Alexion has developed and commercializes two approved complement inhibitors to treat patients with paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS), as well as the first and only approved complement inhibitor to treat anti-acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG) and neuromyelitis optica spectrum disorder (NMOSD) in patients who are anti-aquaporin-4 (AQP4) antibody positive. Alexion also has two highly innovative enzyme replacement therapies and the first and only approved therapies for patients with life-threatening and ultra-rare metabolic disorders, hypophosphatasia (HPP) and lysosomal acid lipase deficiency (LAL-D). With the acquisition of Portola Pharmaceuticals, Inc. (Portola) in July 2020, we added the first and only approved Factor Xa inhibitor reversal agent for patients treated with rivaroxaban or apixaban when reversal of anticoagulation is needed due to life-threatening or uncontrolled bleeding.

In addition to our marketed therapies, we have a diverse pipeline resulting from internal innovation and business development. Alexion focuses its research efforts on novel molecules and targets in the complement cascade and its development efforts on the core therapeutic areas of hematology, nephrology, neurology, metabolic disorders, cardiology, ophthalmology and acute care. We were incorporated in 1992 under the laws of the State of Delaware.

Merger Agreement with AstraZeneca

On December 12, 2020, we entered into an Agreement and Plan of Merger (the Merger Agreement) with AstraZeneca PLC, a public limited company incorporated under the laws of England and Wales (AstraZeneca), Delta Omega Sub Holdings Inc., a Delaware corporation and a wholly owned subsidiary of AstraZeneca (Bidco), Delta Omega Sub Holdings Inc. 1, a Delaware corporation and a direct, wholly owned subsidiary of Bidco (Merger Sub I) and Delta Omega Sub Holdings LLC 2, a Delaware limited liability company and a direct, wholly owned subsidiary of Bidco (Merger Sub II). The Merger Agreement provides, among other things, that subject to the satisfaction or waiver of the conditions set forth therein (1) Merger Sub I will merge with and into Alexion (the “First Merger”), with Alexion surviving the First Merger as a wholly owned subsidiary of Bidco, and (2) immediately following the effective time of the First Merger (the Effective Time), Alexion will merge with and into Merger Sub II (the Second Merger and, together with the First Merger, the Mergers), with Merger Sub II surviving the Second Merger as a wholly owned subsidiary of Bidco and an indirect wholly owned subsidiary of AstraZeneca.

Under the Merger Agreement, at the Effective Time (as defined in the Merger Agreement), each share of common stock, par value $0.0001 per share, of Alexion issued and outstanding immediately prior to the Effective Time (other than certain excluded shares as described in the Merger Agreement) will be converted into the right to receive (1) 2.1243 American depositary shares of AstraZeneca (or, at the election of the holder thereof, a number of ordinary shares of AstraZeneca equal to the number of underlying ordinary shares represented by such American depositary shares) and (2) $60.00 in cash, without interest (collectively, the Merger Consideration).

The boards of directors of both companies have unanimously approved the acquisition.

The respective obligations of Alexion and AstraZeneca to consummate the transactions contemplated by the Merger Agreement are subject to the satisfaction or waiver of a number of customary conditions, including: (1) the adoption of the Merger Agreement by Alexion’s stockholders; (2) approval of the transactions contemplated by the Merger Agreement by AstraZeneca’s shareholders; (3) the absence of any law or order prohibiting consummation of the Mergers; (4) AstraZeneca’s registration statement on Form F-4 having been declared effective by the Securities and Exchange Commission; (5) AstraZeneca’s shareholder circular (or, if required, prospectus) having been approved by the U.K. Financial Conduct Authority; (6) the American depository shares of AstraZeneca issuable in the Mergers (and the ordinary shares of AstraZeneca represented thereby) having been approved for listing on the Nasdaq; (7) the expiration or early termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the approval of the Mergers under the antitrust and foreign investment laws of other specified jurisdictions; (8) accuracy of the other party’s representations and warranties, subject to

certain materiality standards set forth in the Merger Agreement and (9) compliance by the other party in all material respects with such other party’s obligations under the Merger Agreement.

Without limiting the generality of the foregoing, we are subject to a variety of specified restrictions under the Merger Agreement. Unless we obtain AstraZeneca’s prior written consent (which consent may not be unreasonably withheld, conditioned or delayed) and except (i) as required or expressly contemplated by the Merger Agreement, (ii) as required by applicable law or (iii) as set forth in the confidential disclosure schedule delivered by Alexion to AstraZeneca, we may not, among other things and subject to certain exceptions and aggregate limitations, incur additional indebtedness, issue additional shares of our common stock outside of our equity incentive plans, repurchase our common stock, pay dividends, acquire assets, securities or property, dispose of businesses or assets, enter into material contracts or make certain additional capital expenditures.

Under the Merger Agreement, Alexion will be required to make a payment to AstraZeneca equal to $1,180.0 if the Merger Agreement is terminated in certain circumstances, including because the Alexion board of directors has changed its recommendation in favor of the Mergers or we terminated the Merger Agreement in order to enter into an agreement providing for a Company Superior Proposal (as defined in the Merger Agreement), and Alexion will be required to make a payment to AstraZeneca equal to $270.0 if the Merger Agreement is terminated because Alexion’s stockholders fail to adopt the Merger Agreement. AstraZeneca will be required to make a payment to Alexion equal to $1,415.0 if the Merger Agreement is terminated in certain circumstances, including because the AstraZeneca board of directors has changed its recommendation in favor of the Mergers or because AstraZeneca’s shareholders fail to approve the transactions contemplated by the Merger Agreement.

The acquisition is expected to close during the third quarter 2021, and upon completion, Alexion stockholders will own approximately 15.0% of the combined company.

Basis of Presentation and Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Alexion and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. For each of our business combinations, all of the assets acquired and liabilities assumed were recorded at their respective fair values as of the date of acquisition, and their results of operations are included in the consolidated financial statements from the date of acquisition.

Use of Estimates

Preparation of the consolidated financial statements in conformity with U.S. GAAP requires us to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities, revenues, expenses and disclosure of contingent liabilities in our consolidated financial statements.

Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy and financial markets. The full extent to which the COVID-19 pandemic will directly or indirectly impact our business, results of operations and financial condition, including sales, expenses, reserves and allowances, manufacturing, clinical trials, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain. We are not aware of any specific event or circumstance that would require an update to our estimates, judgments and assumptions or a revision of the carrying value of our assets or liabilities as of February 8, 2021, the date of issuance of this Annual Report on Form 10-K. These estimates may change, as new events occur and additional information is obtained. Actual results may differ from these estimates under different assumptions or conditions and such differences may be material.

Dividend Policy

We have never paid a cash dividend on shares of our stock. We currently intend to retain our earnings to finance future operations and do not anticipate paying any cash dividends on our stock in the foreseeable future.

Critical Accounting Estimates

The preparation of our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the U.S., requires us to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities, revenues, expenses and related disclosure of contingent assets and liabilities in our financial statements. We believe the most complex judgments result primarily from the need to make estimates about the effects of matters that are inherently uncertain and are significant to our

consolidated financial statements. We base our estimates on historical experience and on various other assumptions that we believe are reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. We evaluate our estimates, judgments and assumptions on an ongoing basis. Actual results may differ from these estimates under different assumptions or conditions and such differences may be material.

The most significant areas involving estimates, judgments and assumptions used in the preparation of our consolidated financial statements are as follows:

•Revenue recognition;

•Contingent liabilities;

•Share-based compensation;

•Valuation of acquired assets, including goodwill, intangible assets and inventory;

•Valuation of contingent consideration; and

•Income taxes.

Foreign Currency Translation

The financial statements of our subsidiaries with functional currencies other than the U.S. dollar are translated into U.S. dollars using period-end exchange rates for assets and liabilities, historical exchange rates for stockholders’ equity and weighted average exchange rates for operating results. Translation gains and losses are included in accumulated other comprehensive income (loss), net of tax, in stockholders’ equity. Foreign currency transaction gains and losses are included in the results of operations in other income and expense.

Cash and Cash Equivalents

Cash and cash equivalents are stated at cost plus accrued interest, which approximates fair value, and include short-term highly liquid investments with original maturities of three months or less. As of December 31, 2020 and 2019, cash equivalents were comprised of money market funds and other debt securities with maturities less than three months from the date of purchase.

Fair Value of Financial Instruments

The carrying amounts reflected in the consolidated balance sheets for cash and cash equivalents, accounts receivable, other assets, accounts payable, accrued expenses and other liabilities approximate fair value due to their short-term maturities. Our marketable securities are valued based upon pricing of securities with similar investment characteristics and holdings. Our mutual fund investments and equity securities are valued based on quoted market prices in active markets with no valuation adjustment. Investments in equity securities of publicly traded companies which are subject to holding period restrictions are carried at fair value using an option pricing valuation model and observable market inputs such as the historical volatility of similar companies and risk-free interest rates. Our derivative financial instruments are measured at fair value using observable market inputs such as forward rates, interest rates, our own credit risk and our counterparties’ credit risks. Our credit agreement and royalty-based debt obligations are recorded at historical cost, which approximates fair value. Our contingent consideration liabilities related to our acquisitions and derivative liabilities associated with certain option agreements are valued based on various estimates, including probability of success, estimated revenues, discount rates and amount of time until the conditions of the milestone payments are met.

Marketable Securities

We invest our excess cash balances in marketable securities of highly rated financial institutions and investment-grade debt instruments. We seek to diversify our investments and limit the amount of investment concentrations for individual institutions, maturities and investment types. We classify marketable debt securities as available-for-sale and, accordingly, record such securities at fair value. We classify these securities as current assets as these investments are intended to be available to the Company for use in funding current operations.

Credit losses related to our available-for-sale debt securities are recorded through an allowance for credit losses within operating results and are limited to the amount by which the carrying value of the security exceeds its fair value. Unrealized gains and losses on our marketable debt securities related to interest rate changes and other

factors are included in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity.

We sponsor a nonqualified deferred compensation plan which allows certain highly-compensated employees to elect to defer income to future periods. Participants in the plan earn a return on their deferrals based on several investment options, which mirror returns on underlying mutual fund investments. We choose to invest in the underlying mutual fund investments to offset the liability associated with our nonqualified deferred compensation plan. These mutual fund investments are valued at net asset value per share and are carried at fair value with gains and losses included in investment income. The changes in the underlying liability to the employee are recorded in operating expenses.

Accounts Receivable

Our standard credit terms vary based on the country of sale and range from 30 to 120 days and all arrangements are payable within one year of the transfer of the product. Our consolidated average days’ sales outstanding ranges from 70 to 80 days. We evaluate the creditworthiness of customers on a regular basis. The length of time from sale to receipt of payment in certain countries exceeds our credit terms. In countries in which collections from customers extend beyond normal payment terms, we seek to collect interest. We record interest on customer receivables as interest income when collected. We monitor economic conditions and calculate allowances for estimated credit losses on our trade accounts receivable on a quarterly basis using an expected loss model. We assess whether collectibility is probable at the time of sale and on an ongoing basis. We use judgment as to our ability to collect outstanding receivables and provide allowances for the portion of receivables if and when collection becomes doubtful. As of December 31, 2020 and 2019, allowances on receivables were not material.

Concentration of Credit Risk

Financial instruments that potentially expose the Company to concentrations of credit risk are limited to cash equivalents, marketable securities, accounts receivable and our foreign exchange derivative contracts. We invest our cash reserves in money market funds or high-quality marketable debt securities in accordance with our investment policy. The stated objectives of our investment policy are to preserve capital, provide liquidity consistent with forecasted cash flow requirements, maintain appropriate diversification and generate returns relative to these investment objectives and prevailing market conditions.

As of December 31, 2020, four customers accounted for 66.8% of the accounts receivable balance, with these individual customers ranging from 11.7% to 22.1% of the accounts receivable balance. As of December 31, 2019, four customers accounted for 66.9% of the accounts receivable balance, with these individual customers ranging from 11.6% to 20.3% of the accounts receivable balance.

For the year ended December 31, 2020, three customers accounted for 47.4% of our product sales, with these individual customers ranging from 14.7% to 16.7% of our product sales. For the year ended December 31, 2019, four customers accounted for 56.4% of our product sales, with these individual customers ranging from 10.0% to 16.8% of our product sales. For the year ended December 31, 2018, four customers accounted for 50.3% of our product sales, with these individual customers ranging from 10.0% to 16.4% of our product sales. No other customers accounted for more than 10.0% of accounts receivable or net product sales.

We continue to monitor economic conditions, including volatility associated with international economies and the associated impacts on the financial markets and our business. We disaggregate our trade accounts receivable population into pools of similar risk characteristics based on underlying customer type and geographical location and assess current expected credit loss allowances based on available information. Substantially all of our accounts receivable are due from wholesale distributors, public hospitals and other government entities. We monitor the financial performance of our customers so that we can appropriately respond to changes in their credit worthiness. We operate in certain jurisdictions where weakness in economic conditions can result in extended collection periods. To date, we have not experienced any significant losses with respect to collection of our accounts receivable.

Inventories

Inventories are stated at the lower of cost or net realizable value. Cost is determined in a manner that approximates average costs.

The components of inventory are as follows:


	December 31,
	2020		2019
Raw materials	$	91.2	$	41.2
Work-in-process	260.8		180.8
Finished goods	510.3		405.6
	$	862.3	$	627.6

Balance Sheet Classification:
Inventories	$	775.7	$	627.6
Other assets	$	86.6	$	—

Total inventories include ANDEXXA inventory acquired in connection with the July 2, 2020 Portola acquisition, but exclude acquired ANDEXXA validation batches of $60.9 that were manufactured under processes which are subject to regulatory approval. The acquired ANDEXXA inventory includes the acquisition-date fair value step-up, which is expensed within cost of sales as the inventory is sold to customers. For additional information on our acquisition of Portola, please refer to Note 2, Acquisitions.

We classify our inventory costs as long-term when we expect to utilize the inventory beyond our normal operating cycle and include these costs in other assets in our consolidated balance sheets. Inventories classified as long-term relate to ANDEXXA inventory, including inventory acquired in connection with the Portola acquisition.

Capitalization of Inventory Costs

We capitalize inventory produced for commercial sale, which may include costs incurred for certain products awaiting regulatory approval, or for inventory produced at new production facilities, when management considers it probable that the pre-approval inventories will be saleable. We capitalize inventory produced in preparation of product launches sufficient to support estimated initial market demand. Capitalization of such inventory begins when we have (i) obtained positive results in clinical trials that we believe are necessary to support regulatory approval, (ii) concluded that uncertainties regarding regulatory approval of the product and facilities have been sufficiently reduced, and (iii) determined that the inventory has probable future economic benefit. In evaluating whether these conditions have been met, we consider clinical trial results for the underlying product candidate, results from meetings with regulatory authorities, the compilation of the regulatory application, and how far a facility has progressed along the approval process. If we are aware of any material risks or contingencies outside of the standard regulatory review and approval process, or if there are any specific negative issues identified relating to the safety, efficacy, manufacturing, marketing or labeling of the product that would have a significant negative impact on its future economic benefits, the related inventory would not be capitalized. As of December 31, 2020 and 2019, the carrying value of inventory at unapproved production facilities was $39.8 and $60.5, respectively. We also capitalize costs associated with technology transfer, including engineering and validation activities, to our external CMO’s within prepaid expenses and other current assets and other assets in our consolidated balance sheets. Upon regulatory approval, saleable inventory produced during the validation process is reclassified to inventory and expensed to cost of goods sold as the product is sold. Any costs associated with non-saleable inventory will remain in prepaid expenses and other current assets and other assets in our consolidated balance sheets, and will be amortized to costs of goods sold over the remaining life of the contract.

Products that have been approved by the U.S. Food and Drug Administration (FDA) or other regulatory authorities are also used in clinical programs to assess the safety and efficacy of the products for usage in diseases that have not been approved by the FDA or other regulatory authorities. The form of the products utilized for both commercial and clinical programs is identical and, as a result, the inventory has an “alternative future use” as defined in authoritative guidance. Raw materials and purchased drug product associated with clinical development programs are included in inventory and charged to research and development expense when the product enters the research and development process and no longer can be used for commercial purposes and, therefore, does not have an “alternative future use”.

For products which are under development and have not yet been approved by regulatory authorities, purchased drug product is charged to research and development expense upon delivery. Delivery occurs when the inventory passes quality inspection and ownership transfers to us. Nonrefundable advance payments for research and development activities, including production of purchased drug product, are deferred and capitalized until the goods are delivered. We also recognize expense for raw materials purchased for developmental purposes when the raw materials pass quality inspection and we have an obligation to pay for the materials.

Inventory Write-Offs

We analyze our inventory levels to identify inventory that may expire prior to sale, inventory that has a cost basis in excess of its estimated realizable value, or inventory in excess of expected sales requirements. Although the manufacturing of our products are subject to strict quality control, certain batches or units of product may no longer meet quality specifications or may expire, which requires adjustments to our inventory values. We also apply judgment related to the results of quality tests that we perform throughout the production process, as well as our understanding of regulatory guidelines, to determine if it is probable that inventory will be saleable. These quality tests are performed throughout the pre-and post-production process, and we continually gather additional information regarding product quality for periods after the manufacture date. Our products currently have a maximum estimated life ranging from 36 to 48 months, and based on our sales forecasts, we expect to realize the carrying value of our inventory. In the future, reduced demand, quality issues or excess supply beyond those anticipated by management may result in a material adjustment to inventory levels, which would be recorded as an increase to cost of sales.

The determination of whether or not inventory costs will be realizable requires estimates by our management. A critical input in this determination is future expected inventory requirements based on internal sales forecasts. We then compare these requirements to the expiry dates of inventory on hand. For inventories that are capitalized in preparation of product launch, we also consider the expected approval date in assessing realizability. To the extent that inventory is expected to expire prior to being sold, we will write down the value of inventory.

Derivative Instruments

We record the fair value of derivative instruments as either assets or liabilities on the balance sheet. The accounting for gains and losses resulting from changes in fair value is dependent on the use of the derivative and whether it is designated and qualifies for hedge accounting.

All qualifying hedging activities are documented at the inception of the hedge and must meet the definition of highly effective in offsetting changes to future cash. On a quarterly basis, we perform an assessment to confirm that outstanding hedges remain highly effective and continue to qualify for hedge accounting. We record the fair value of the qualifying hedges in prepaid expenses and other current assets, other assets, other current liabilities and other liabilities. All unrealized gains and losses on derivatives that are designated and qualify for hedge accounting are reported in other comprehensive income (loss) and recognized when the underlying hedged transaction affects earnings. When the forecasted transaction occurs, this amount is reclassified into the consolidated statement of operations and presented in the same financial statement line item as the hedged item.

Derivative instruments for which hedge accounting is not applied are recorded at fair value in prepaid expenses and other current assets and other current liabilities. Unrealized gains and losses resulting from changes in the fair value of these derivatives are reported in other income and expense.

Property, Plant and Equipment

Property, plant and equipment are stated at cost and are depreciated on a straight-line basis over the estimated useful lives of the assets. We estimate economic lives as follows:

•Building and improvements—fifteen to thirty-five years

•Machinery and laboratory equipment—five to fifteen years

•Computer hardware and software—three to seven years

•Furniture and office equipment— five to ten years

Leasehold improvements and assets under financing lease arrangements are amortized over the lesser of the asset’s estimated useful life or the term of the respective lease. Maintenance costs are expensed as incurred.

Construction-in-progress reflects amounts incurred for property, plant, or equipment construction or improvements that have not been placed in service.

Leases

In February 2016, the FASB issued a new standard that requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. We adopted the new standard on January 1, 2019 using the modified retrospective approach. Upon adoption of the new lease standard, on January 1, 2019, we derecognized $472.8 of property, plant and equipment and other assets and $372.2 of facility lease obligations associated with previously existing build-to suit arrangements. We capitalized right of use (ROU) assets of $326.1, inclusive of opening adjustments of $70.8 primarily related to prepaid rent existing at transition, and $255.3 of lease liabilities, within our consolidated balance sheets upon adoption. At transition, we recorded a decrease of $90.3 to retained earnings, net of tax, primarily related to our derecognition of previously recorded build-to-suit arrangements.

At the inception of an arrangement, we determine if an arrangement is, or contains, a lease based on the unique facts and circumstances present in that arrangement. Lease classification, recognition, and measurement are then determined at the lease commencement date. For arrangements that contain a lease we (i) identify lease and non-lease components, (ii) determine the consideration in the contract, (iii) determine whether the lease is an operating or financing lease; and (iv) recognize lease ROU assets and liabilities. Lease liabilities and their corresponding ROU assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable and as such, we use our incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment.

Most leases include options to renew and, or, terminate the lease, which can impact the lease term. The exercise of these options is at our discretion and we do not include any of these options within the expected lease term as we are not reasonably certain we will exercise these options. We have elected to combine lease components (for example fixed payments including rent) with non-lease components (for example, non-dedicated parking and common-area maintenance costs) on our real estate and commercial fleet asset classes. We separate lease and non-lease components on our embedded contract manufacturing organization (CMO) arrangements. Lease and non-lease components on these CMO arrangements are determined based on an allocation of the consideration in the contract to the embedded lease and non-lease components of the arrangement based on the relative standalone prices of these components.

Fixed, or in substance fixed, lease payments on operating leases are recognized over the expected term of the lease on a straight-line basis, while fixed, or in substance fixed, payments on financing leases are recognized using the effective interest method. Variable lease expenses that are not considered fixed, or in substance fixed, are recognized as incurred. Fixed and variable lease expense on operating leases is recognized within operating expenses within our consolidated statements of operations. Financing lease ROU asset amortization and interest costs are recorded within operating expenses and interest expense, respectively, within our consolidated statements of operations. We have operating and financing leases for corporate offices, research and development facilities, regional executive and sales offices, commercial fleet, and CMO embedded lease arrangements. We have elected the short-term lease exemption and, therefore, do not recognize a ROU asset or corresponding liability for lease arrangements with an original term of 12 months or less.

Operating leases are included in right of use operating assets, other current liabilities, and noncurrent operating lease liabilities in our consolidated balance sheet as of December 31, 2020 and 2019. Financing leases are included in property, plant and equipment, other current liabilities, and other liabilities in our consolidated balance sheet as of December 31, 2020 and 2019.

Manufacturing Facilities

We capitalize costs incurred for the construction of facilities which support commercial manufacturing. We also capitalize costs related to validation activities which are directly attributable to preparing the facility for its intended use, including engineering runs and inventory production necessary to obtain approval of the facility from government regulators for the production of a commercially approved drug. When the facility is substantially complete and ready

for its intended use and regulatory approval for commercial production has been received, we will place the asset in service.

The production of inventory for preparing the facility for its intended use requires two types of production: engineering runs which are used for testing purposes only and do not result in saleable inventory, and validation runs which are used for validating equipment and may result in saleable inventory. The costs associated with inventory produced during engineering runs and normal production losses during validation runs are capitalized to fixed assets and depreciated over the asset’s useful life. Saleable inventory produced during the validation process is initially recorded as a fixed asset; however, upon regulatory approval, this inventory is reclassified to inventory and expensed in cost of goods sold as product is sold, or in research and development expenses as product is utilized in R&D activities. Abnormal production costs incurred during the validation process are expensed as incurred.

Acquisitions

Business combinations are accounted for using the acquisition method of accounting. Under the acquisition method of accounting, the tangible and intangible assets acquired and the liabilities assumed are recorded as of the acquisition date at their respective fair values. We evaluate a business as an integrated set of activities and assets that is capable of being conducted and managed for the purpose of providing a return in the form of dividends, lower costs or other economic benefits and consists of inputs and substantive processes applied to those inputs that have the ability to contribute to the creation of outputs. If substantially all of the fair value of gross assets acquired is concentrated in a single asset or group of similar identifiable assets, the assets do not represent a business. In an acquisition of a business, the excess of the fair value of the consideration transferred over the fair value of the net assets acquired is recorded as goodwill.

Acquisitions of assets or a group of assets that do not meet the definition of a business are accounted for as asset acquisitions using the cost accumulation method, whereby the cost of the acquisition, including certain transaction costs, is allocated to the assets acquired on the basis of relative fair values. No goodwill is recognized in an asset acquisition. Intangible assets that are acquired in an asset acquisition for use in research and development activities which have an alternative future use are capitalized as in-process research and development (IPR&D). Acquired IPR&D which has no alternative future use is recognized as research and development expense at acquisition. Contingent milestone payments associated with asset acquisitions are recognized when probable and estimable. These amounts are expensed to research and development if there is no alternative future use associated with the asset, or capitalized as an intangible asset if alternative future use of the asset exists.

Our consolidated financial statements include the results of operations of an acquired business after the completion of the acquisition.

Contingent Consideration

We record contingent consideration resulting from a business combination at fair value on the acquisition date. On a quarterly basis, we revalue these obligations and record increases or decreases in their fair value as an adjustment to operating earnings. Changes to contingent consideration obligations can result from adjustments to discount rates, accretion of the liability due to the passage of time, changes in our estimates of the likelihood or timing of achieving development or commercial milestones, changes in the probability of certain clinical events or changes in the assumed probability associated with regulatory approval.

Intangible Assets

Intangible assets related to IPR&D projects are considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts. During the period the assets are considered indefinite-lived, they will not be amortized but will be tested for impairment. Impairment testing is performed at least annually or when a triggering event occurs that could indicate a potential impairment. If and when development is complete, which generally occurs when regulatory approval to market a product is obtained, the associated assets are deemed finite-lived and are amortized over a period that best reflects the economic benefits provided by these assets.

Goodwill

Goodwill represents the excess of purchase price over fair value of net assets acquired in a business combination and is not amortized. Goodwill is subject to impairment testing at least annually or when a triggering event occurs that could indicate a potential impairment. We are organized and operate as a single reporting unit and therefore the goodwill impairment test is performed using our overall market value, as determined by our traded share price, compared to our book value of net assets.

Impairment of Long-Lived Assets

Our long-lived assets are primarily comprised of intangible assets, right of use assets and property, plant and equipment. We evaluate our finite-lived intangible assets, right of use assets and property, plant and equipment for impairment whenever events or changes in circumstances indicate the carrying value of an asset or group of assets is not recoverable. If these circumstances exist, recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset group to future undiscounted net cash flows expected to be generated by the asset group. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets.

In addition, indefinite-lived intangible assets, comprised of IPR&D, are reviewed for impairment annually and whenever events or changes in circumstances indicate that it is more likely than not that the asset is impaired by comparing the fair value to the carrying value of the asset.

If the carrying value of a finite-lived intangible asset is not recoverable, or if there is an indicator of impairment on an indefinite-lived intangible asset, we will recognize an impairment in the amount by which the carrying value of the asset exceeds its fair value. We calculate the fair value of these assets using discounted cash flow models which require the use of significant estimates and judgements which include, but are not limited to, timing and costs to complete the in-process projects, timing and probability of success of clinical events or regulatory approvals, estimated future cash flows from product sales resulting from completed products and in-process projects, tax rates and discount rates. Changes to assumptions used in our cash flow projections could result in an impairment. Impairments are recorded within impairment of intangible assets in our consolidated statements of operations.

During the year-ended December 31, 2020, we recognized impairment charges of $2,053.3, related to a $2,042.3 impairment charge of our KANUMA intangible asset and an impairment charge of $11.0 to write off the cost basis of our ACHN-4471 (ALXN2040) acquired in-process research and development asset. Refer to Note 4, Intangible Assets and Goodwill, for additional information on the impairment charges recorded.

Other Investments

From time to time, we make strategic investments in equity securities of certain biotechnology companies which we acquire in connection with license and option agreements. Our strategic investment portfolio may include equity securities in publicly traded companies, as well as investments in companies with securities that are not publicly traded and where fair value is not readily available. These investments are included in other assets in our consolidated balance sheets.

We record our investments in securities that are not publicly traded at cost, less impairments and also adjust the investment for any changes resulting from an observable price change in an orderly transaction for identical or similar investments of the same issuer. We assess relevant transactions that occur on or before the balance sheet date to identify observable price changes, and we regularly monitor these investments to evaluate whether there is an indication that the investment is impaired, based on the implied value of recent company financings, public market prices of comparable companies, and general market conditions.

Our investments in equity securities in publicly traded companies which are unrestricted are regularly measured and carried at fair value and classified as Level 1 equity securities within the fair value hierarchy. Investments in publicly traded companies which are subject to holding period restrictions are carried at fair value using an option pricing valuation model and classified as Level 2 equity securities within the fair value hierarchy. The most significant assumptions within the option pricing valuation model are the term of the restrictions and the stock price volatility, which is based upon the historical volatility of the applicable company or similar companies.

Contingent Liabilities

We are currently involved in various claims and legal proceedings. On a quarterly basis, we review the status of each significant matter and assess its potential financial exposure. If the potential loss from any claim, asserted or unasserted, or legal proceeding is considered probable and the amount can be reasonably estimated, we accrue a liability for the estimated loss. Because of uncertainties related to claims and litigation, accruals are based on the best information available at the time of our assessment including the legal facts and circumstances of the case, status of the proceedings, applicable law and the likelihood of settlement, if any. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation or settlement of claims (and our offers of settlement), we may reassess the potential liability related to these matters and may revise these estimates when facts and circumstances indicate the need for changes.

Treasury Stock

Treasury stock is accounted for using the cost method, with the purchase price of the common stock recorded separately as a deduction from stockholders’ equity.

Revenue Recognition

In May 2014, the FASB issued a comprehensive new standard which amends revenue recognition principles. We adopted the new standard on January 1, 2018 by applying the modified retrospective method to all contracts that were not completed as of that date. Under the new guidance, revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration expected to be received in exchange for those goods or services. Revenue is recognized through a five-step process: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) a performance obligation is satisfied. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, the Company assesses the goods or services promised within each contract, and determines those that are performance obligations. Revenue is recognized for the applicable performance element when each distinct performance obligation is satisfied.

Upon adoption of the new revenue recognition standard, on January 1, 2018, we reduced our deferred revenue balance by $10.4, with an offsetting increase of $6.0 in retained earnings due to the cumulative impact of adopting this new standard. The impact to net product sales and net income for the year ended December 31, 2018 was an increase of $5.3 and $4.8, respectively. The new standard also resulted in a decrease of $17.9 in deferred revenue and an increase of $10.8 in retained earnings as of December 31, 2018. The adoption of the new revenue standard did not have a material impact on any other balances within the consolidated financial statements as of and for the year ended December 31, 2018. The adoption of the new standard did not significantly change our accounting policies.

Nature of Products

Our principal source of revenue is product sales. Our contracts with customers generally contain a single performance obligation and we recognize revenue from product sales when we have satisfied our performance obligation by transferring control of the product to our customers. Control of the product generally transfers to the customer upon delivery. In certain countries, we sell to distributors on a consignment basis and record revenue when control of the product transfers to the customer upon sale to the end user.

Our customers are primarily comprised of distributors, pharmacies, hospitals, hospital buying groups, and other healthcare providers. In some cases, we may also sell to governments and government agencies. In addition to sales in countries where our products are commercially available, we have also recorded revenue on sales for patients receiving treatment through named-patient programs. The relevant authorities or institutions in those countries have agreed to reimburse for product sold on a named-patient basis where our products have not received final approval for commercial sale.

Revenue is recognized at the amount to which we expect to be entitled in exchange for the sale of our products. This amount includes both fixed and variable consideration and excludes amounts that are collected from customers and remitted to governmental authorities, such as value-added taxes in foreign jurisdictions. Shipping and handling costs associated with outbound freight after control of a product has

transferred to our customers are accounted for as a fulfillment cost and are included in operating expenses. The cost for any shipping and handling activities (including customs clearance activities) associated with transactions for which revenue has been recognized are accrued if not completed before the respective period end.

The timing between the recognition of revenue for product sales and the receipt of payment is not significant. Our standard credit terms, which vary based on the country of sale, range from 30 to 120 days and all arrangements are payable within one year of the transfer of the product. We do not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between the transfer of the promised good to the customer and receipt of payment will be one year or less.

Variable Consideration

We pay distribution fees to our distributors and offer rebates and/or discounts, or enter into volume-based reimbursement arrangements with certain customers. We reduce the transaction price on our sales for these amounts. For variable amounts, we estimate the amount of consideration to which we expect to be entitled based on all available historic, current and forecast information. We primarily use the expected value method to estimate variable payments and, in limited circumstances, will apply the most likely method based on the type of variable consideration and what method better predicts the amount of consideration we expect to be entitled to. Consideration that is received from a customer that we expect will need to be refunded in the future is recorded as a refund liability to the customer within accrued expenses. Actual amounts of consideration ultimately received or refunded may differ from our estimates. If actual results in the future vary from our estimates, we adjust these estimates, which would affect net product sales and earnings in the period such variances become known.

Variability in the transaction price for our products pursuant to our contracts with customers primarily arises from the following:

Discounts and Rebates: We offer discounts and rebates to certain distributors and customers under our arrangements. In many cases, these amounts are fixed at the time of sale and the transaction price is reduced accordingly. We also provide for rebates under certain governmental programs, including Medicaid in the U.S. and other programs outside the U.S., which are payable based on actual claim data. We estimate these rebates based on an analysis of historical claim patterns and estimates of customer mix to determine which sales will be subject to rebates and the amount of such rebates. We update our estimates and assumptions each period and record any necessary adjustments, which may have an impact on revenue in the period in which the adjustment is made. Generally, the length of time between product sale and the processing and reporting of the rebates is three to six months.

Volume-Based Arrangements: We have entered into volume-based arrangements with governments in certain countries and other customers in which reimbursement is limited to a contractual amount. Under this type of arrangement, amounts billed in excess of the contractual limitation are repaid to the customer as a rebate. We estimate incremental discounts resulting from these contractual limitations, based on forecasted sales during the limitation period, and we apply the discount percentage to product shipments as a reduction of revenue. Our calculations related to these arrangements require estimation of sales during the limitation period, and adjustments in these estimates may have a material impact in the period in which these estimates change.

Distribution & Other Fees: We pay distribution and other fees to certain customers in connection with the sales of our products. We record distribution and other fees paid to our customers as a reduction of revenue, unless the payment is for a distinct good or service from the customer and we can reasonably estimate the fair value of the goods or services received. If both conditions are met, we record the consideration paid to the customer as an operating expense. These costs are typically known at the time of sale, resulting in minimal adjustments subsequent to the period of sale.

Product Returns: Our contracts with customers for ULTOMIRIS, SOLIRIS, STRENSIQ, and KANUMA generally provide for returns only if the product is damaged or defective upon delivery. Because of factors such as the price of our products, the limited number of patients, the short period from product sale to patient infusion and limited contractual return rights for SOLIRIS, ULTOMIRIS, STRENSIQ and KANUMA, our customers often carry limited inventory. Our contracts with customers for ANDEXXA generally provide for returns if the product

is damaged or defective upon delivery and if the product is within an eligible expiry window. While ANDEXXA inventory on hand is also limited, there may be a longer period from product sale to patient use and a greater risk of return for product expiry. We assess our sales transactions and arrangements with customers and monitor inventory within our sales channels to determine whether a provision for returns is warranted and a resulting adjustment to the transaction price is necessary. This assessment is based on historical experience and assumptions as of the date of sale and changes in these estimates could have an impact in the period in which the change occurs.

The amount of variable consideration included in the transaction price is constrained by the amount that is probable will not result in a significant reversal of revenue. We consider our experience with similar transactions and expectations regarding the contract in estimating the amount of variable consideration to which we expect to be entitled, and determining whether the estimated variable consideration should be constrained. We do not have any material constraints on the variable consideration included within the transaction price of our current revenue arrangements.

Refer to Note 18, Segment Information for a summary of revenue from contracts with customers by product and geographical region.

Contract Balances and Receivables

Contract liabilities relate to consideration received and/or billed for goods that have not been delivered to the customer and for which the performance obligation has not yet been completed. These amounts are included within other current liabilities in the consolidated statements of operations.

The following table provides information about receivables and contract liabilities from our contracts with customers.


	December 31, 2020		December 31, 2019
Receivables, which are included in "Trade accounts receivable, net"	$	1,409.3	$	1,243.2
Contract liabilities, which are included in "Other current liabilities"	$	3.0	$	6.8

Contract balances and receivables associated with collaboration agreements assumed through the acquisition of Portola in the third quarter 2020, which were included in the table above, were not material as of December 31, 2020.

Research and Development Expenses

Research and development expenses are comprised of costs incurred in performing research and development activities including payroll and benefits, preclinical, clinical trial and related clinical manufacturing costs, manufacturing development and scale-up costs, product development and regulatory costs, contract services and other outside contractor costs, research license fees, depreciation and amortization of lab facilities, and lab supplies. These costs are expensed as incurred. We accrue costs for clinical trial activities based upon estimates of the services received and related expenses incurred that have yet to be invoiced by the contract research organizations, clinical study sites, laboratories, consultants, or other clinical trial vendors that perform the activities.

Share-Based Compensation

We have two share-based compensation plans pursuant to which awards are currently being made: (i) the 2017 Incentive Plan (2017 Plan) and (ii) the 2015 Employee Stock Purchase Plan (ESPP). The 2017 Plan replaced the Amended & Restated 2004 Incentive Plan (2004 Plan), effective May 10, 2017. Under the 2017 Plan, restricted stock, restricted stock units, stock options and other stock-related awards may be granted to our directors, officers, employees and consultants or advisors of the Company or any subsidiary. Under the ESPP, eligible employees can purchase shares of common stock at a discount semi-annually through payroll deductions. To date, share-based compensation issued under the plans consists of incentive and non-qualified stock options, restricted stock and restricted stock units, including restricted stock units with market and non-market performance conditions, and shares issued under our ESPP.

Compensation expense for our share-based awards is recognized based on the estimated fair value of the awards on the grant date. Compensation expense reflects an estimate of the number of awards expected to vest and is primarily recognized on a straight-line basis over the requisite service period of the individual grants, which

typically equals the vesting period. Compensation expense for awards with performance conditions is recognized using the graded-vesting method.

Our estimates of employee stock option values rely on estimates of factors we input into the Black-Scholes model. The key factors involve an estimate of future uncertain events. Assumptions include the use of historical volatility to determine the expected stock price volatility. We also estimate expected term until exercise and the reduction in the expense from expected forfeitures. We currently use historical exercise and cancellation patterns as our best estimate of future estimated life.

For our non-market performance-based awards, we estimate the anticipated achievement of the performance targets, including forecasting the achievement of future financial targets. These estimates are revised periodically based on the probability of achieving the performance targets and adjustments are made throughout the performance period as necessary. We use payout simulation models to estimate the grant date fair value of awards with market-based performance conditions. The payout simulation models assume volatility of our common stock and the common stock of a comparator group of companies, as well as correlations of returns of the price of our common stock and the common stock prices of the comparator group.

The purchase price of common stock under our ESPP is equal to 85.0% of the lower of (i) the market value per share of the common stock on the first business day of an offering period or (ii) the market value per share of the common stock on the purchase date. The fair value of the discounted purchases made under our ESPP is calculated using the Black-Scholes model. The fair value of the look-back provision plus the 15.0% discount is recognized as compensation expense over the 6 month purchase period.

Restructuring and Restructuring Related Expenses

Restructuring related expenses include accelerated depreciation costs and impairment charges associated with assets impacted by a restructuring exit activity. Accelerated depreciation costs represent the difference between the depreciation expense recognized over the revised useful life of the asset, based upon the anticipated date an impacted site closure, and the depreciation expense as determined using the useful life prior to the restructuring activities.

Earnings Per Common Share

The following table summarizes the calculation of basic and diluted EPS for years ended December 31, 2020, 2019 and 2018:


	Year Ended December 31,
	2020		2019		2018
Net income used for basic and diluted calculation	$	603.4	$	2,404.3	$	77.6
Shares used in computing earnings per common share—basic	220.1		223.2		222.7
Weighted-average effect of dilutive securities:
Stock awards	1.9		1.6		1.8
Shares used in computing earnings per common share—diluted	222.0		224.8		224.5
Earnings per common share:
Basic	$	2.74	$	10.77	$	0.35
Diluted	$	2.72	$	10.70	$	0.35

We exclude from EPS the weighted-average number of securities whose effect is anti-dilutive. Excluded from the calculation of EPS for the years ended December 31, 2020, 2019 and 2018 were 1.7, 3.0 and 2.8 shares of common stock, respectively, because their effect is anti-dilutive.

Income Taxes

We utilize the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement carrying amounts and tax basis of assets and liabilities using enacted tax rates in effect for years in which the temporary differences are expected to reverse. We periodically evaluate the likelihood of the realization of deferred tax assets and reduce the carrying amount of these deferred tax assets by a valuation allowance when it is more likely than not that deferred tax assets will not be realized.

We recognize the benefit of an uncertain tax position that has been taken or we expect to take on income tax returns if such tax position is more likely than not to be sustained. The tax benefit recognized in the financial statements for a particular tax position is based on the largest benefit that is more likely than not to be realized. The amount of unrecognized tax benefits is adjusted, as appropriate, for changes in facts and circumstances, such as significant amendments to existing tax law, new regulations or interpretations by the taxing authorities, or new information obtained during a tax examination or resolution of an examination. We also accrue for potential interest and penalties related to unrecognized tax benefits as a component of tax expense.

During the fourth quarter of 2013, in connection with the centralization of our global supply chain and technical operations in Ireland, our U.S. parent company became a direct partner in a captive foreign partnership. Our corporate structure, which derives income from multiple jurisdictions, requires us to interpret the related tax laws and regulations within those jurisdictions and develop estimates and assumptions regarding significant future events, such as the amount, timing and character of deductions and the applicability of foreign tax credits. From time to time, we execute intercompany transactions that may impact the valuation of the captive foreign partnership and the corresponding interest allocated to each partner, resulting in a change to deferred taxes. The transactions and related valuations require the application of transfer pricing guidelines issued by the relevant taxing authorities. Significant estimates and assumptions within discounted cash flow models are also required to calculate the valuations.

In December 2017, the Tax Cuts and Jobs Act (Tax Act) was enacted into law. The Tax Act decreased the U.S. federal corporate tax rate to 21.0%, imposed a minimum tax on foreign earnings related to intangible assets (GILTI), a one-time transition tax on previously unremitted foreign earnings, and modified the taxation of other income and expense items. With regard to the GILTI minimum tax, foreign earnings are reduced by the profit attributable to tangible assets and a deductible allowance of up to 50.0%, subject to annual limitations. We have elected to account for the impact of the minimum tax in deferred taxes.

Comprehensive Income

Comprehensive income is comprised of net income and other comprehensive income (loss). Other comprehensive income (loss) includes changes in equity that are excluded from net income, such as changes in pension liabilities, unrealized gains and losses on marketable debt securities, unrealized gains and losses on hedge contracts and foreign currency translation adjustments. These changes in equity are reflected net of tax.

Reclassifications

Certain items in the prior year’s consolidated financial statements have been reclassified to conform to the current presentation.

New Accounting Pronouncements

Accounting Standards Update (ASU) 2019-12, “Income Taxes: Simplifying the Accounting for Income Taxes”: In December 2019, the Financial Accounting Standards Board (FASB) issued a new standard intended to simplify the accounting for income taxes by eliminating certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new standard also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The standard is effective for annual periods beginning after December 15, 2020 and interim periods within, with early adoption permitted. Adoption of the standard requires certain changes to be made

prospectively, with some changes to be made retrospectively. We adopted the new standard on January 1, 2021. We have substantially completed our assessment of the standard and we do not expect the adoption of this standard to have a material impact on our financial condition and results of operations.

ASU 2020-01, “Investments - Equity Securities, Investments - Equity Method and Joint Ventures, and Derivatives and Hedging - Clarifying the Interactions Between Topic 321, Topic 323, and Topic 815”: In January 2020, the FASB issued a new standard intended to clarify the interactions between Accounting Standards Codification (ASC) 321, ASC 323 and ASC 815. The new standard addresses accounting for the transition into and out of the equity method and measurement of certain purchased options and forward contracts to acquire investments. The standard is effective for annual and interim periods beginning after December 15, 2020, with early adoption permitted. Adoption of the standard requires changes to be made prospectively. We adopted the new standard on January 1, 2021. The adoption of this standard does not have an impact on our financial condition and results of operations.

ASU 2020-04, “Reference Rate Reform, Facilitation of the Effects of Reference Rate Reform on Financial Reporting": In response to concerns about structural risks of interbank offered rates, and, particularly, the risk of cessation of the London Interbank Offered Rate (LIBOR), regulators around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction-based and less susceptible to manipulation. In March 2020, the FASB issued a new standard that provides optional guidance for a limited time to ease the potential burden in accounting for the effects of reference rate reform, including optional expedients and exceptions for the accounting implications of contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met.

The amendments in this new standard only apply to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. The expedients and exceptions provided by the standard do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. We are currently reviewing our contracts impacted by reference rate reform and are assessing the impact of this standard on our financial condition and results of operations.

Recently Adopted Accounting Pronouncements

ASU 2018-15, "Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract": In August 2018, the FASB issued a new standard on a customer's accounting for implementation, set-up, and other upfront costs incurred in a cloud computing arrangement (CCA) that aligns the requirements for capitalizing implementation costs in a CCA service contract with existing internal-use software guidance. The standard also provides classification guidance on these implementation costs as well as additional quantitative and qualitative disclosures. The standard is effective for interim and annual periods beginning after December 15, 2019, with early adoption permitted, and can be adopted prospectively or retrospectively.

We adopted the new standard on January 1, 2020 on a prospective basis. The adoption of this standard had no impact on our financial statements at the date of adoption; however, we anticipate the adoption of this standard will result in an increase in capitalized assets related to qualifying CCA implementation costs in future periods.

Qualifying CCA implementation, set-up and other upfront costs incurred after January 1, 2020 are capitalized as other assets in our consolidated balance sheets. These assets will be expensed over the term of the hosting arrangement and such expense will be presented within the same line item in our consolidated statements of operations as the expense for fees for the associated hosting arrangement. These capitalized costs will be evaluated for impairment when events or changes in circumstances indicate that the carrying value of the capitalized implementation costs is not recoverable. For the year ended December 31, 2020, capitalized CCA implementation costs were not material.

ASU 2016-13, "Measurement of Credit Losses on Financial Instruments": In June 2016, the FASB issued a new standard intended to improve reporting requirements specific to loans, receivables and other financial instruments. The new standard requires that credit losses on financial assets measured at amortized cost be determined using an expected loss model, instead of the current incurred loss model, and requires that credit losses related to available-for-sale debt securities be recorded through an allowance for credit losses and limited to the amount by which carrying value exceeds fair value. The new standard also requires enhanced disclosure of credit risk associated with financial assets. The standard is effective for interim and annual periods beginning after December 15, 2019 with early adoption permitted.

We adopted the new standard on January 1, 2020 and completed our assessment of the standard based on the composition of our portfolio of financial instruments and current and forecasted economic conditions at that date. Our significant financial assets that are within the scope of the new standard consist of trade accounts receivable and available for sale debt securities. We have not historically experienced any material credit losses associated with our trade accounts receivable or available for debt securities.

We monitor economic conditions, including volatility associated with international economies and the associated impacts on the financial markets and our business. We disaggregate our trade accounts receivable population into pools of similar risk characteristics based on underlying customer type and geographical location. Current expected credit loss allowances are estimated for each risk pool based on available information, including i) historical credit loss experience, ii) current economic conditions and, iii) reasonable and supportable forecasts of future economic conditions that may affect the collectibility of the recorded amounts. Based on the relevant facts and economic conditions as of the date of adoption, we concluded that the expected credit losses on our trade accounts receivable were immaterial. Additionally, unrealized losses on our available for sale investment portfolio were immaterial.

As of December 31, 2020, we reassessed our estimated credit losses on our trade accounts receivable, including consideration of the potential impacts of the COVID-19 global pandemic. Based on the relevant facts and economic conditions as of December 31, 2020, we concluded that the expected credit losses on our trade accounts receivable continued to be immaterial.

Acquisitions

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Acquisitions

Business Combinations

Achillion Pharmaceuticals, Inc.

In October 2019, Alexion entered into a definitive agreement to acquire Achillion Pharmaceuticals, Inc. (Achillion), a clinical-stage biopharmaceutical company focused on the development of oral Factor D inhibitors. Achillion was developing oral small molecule Factor D inhibitors to treat people with complement alternative pathway-mediated rare diseases, such as PNH and C3 glomerulopathy (C3G). Achillion had two clinical stage medicines in development, including danicopan (ACH-4471/ALXN2040) and ACH-5228 (ALXN2050).

The acquisition of Achillion closed on January 28, 2020. Under the terms of the agreement, we acquired all outstanding common stock of Achillion for $6.30 per share, or an aggregate of $926.2, inclusive of the settlement of Achillion's outstanding equity awards. The acquisition was funded with cash on hand. The transaction includes the potential for additional consideration in the form of non-tradeable contingent value rights (CVRs), which will be paid to Achillion shareholders if certain clinical and regulatory milestones are achieved within specified periods. These include $1.00 per share for the U.S. Food and Drug Administration (FDA) approval of danicopan and $1.00 per share for the initiation of a Phase III clinical trial in ACH-5228.

The transaction was accounted for as a business combination. The following table summarizes the total consideration transferred to acquire Achillion and the estimated fair value of the identified assets acquired and liabilities assumed at the acquisition date:


Consideration
Upfront payment to shareholders and option holders	$	926.2
Upfront payment, fair value of equity compensation attributable to the post-combination service period	(20.0)
Upfront cash paid, net	906.2

Contingent consideration	160.7
Contingent consideration, fair value of equity compensation attributable to the post-combination service period	(5.7)
Total consideration	$	1,061.2

Assets Acquired and Liabilities Assumed
Cash and cash equivalents	$	68.5
Marketable securities	106.1
In-process research & development assets (IPR&D)	918.0
Goodwill	37.8
Deferred tax liabilities, net	(62.9)
Other assets and liabilities, net	(6.3)
Total net assets acquired	$	1,061.2

Our accounting for this acquisition was finalized during the second quarter of 2020. Measurement period adjustments increased goodwill by $3.1 during the second quarter of 2020 due to purchase price allocation increases to deferred tax liabilities, net. Measurement period adjustments were recorded as a result of studies completed during the second quarter of 2020 to determine the tax deductibility of certain acquisition-related costs and the valuation of historical net operating loss and income tax credit carryforwards.

The initial fair value estimate of the contingent consideration in the form of non-tradeable CVRs was $160.7, which was recorded as a noncurrent liability in our consolidated balance sheet, including $5.7 related to compensation attributable to the post-combination service period. We determined the fair value of these milestone-related payment obligations using various estimates, including probabilities of success prior to expiration of the specified period, discount rates and the amount of time until the conditions of the milestone payments are expected to be met. This fair value measurement was based on significant inputs not observable in the market, representing Level 3 measurements within the fair value hierarchy. The resulting probability-weighted cash flows were discounted using a cost of debt rate ranging from 2.1% to 2.3%. The range of estimated milestone payments upon closing of the acquisition is from zero, if no milestones are achieved for any product, to $306.3 if certain development and regulatory milestones are achieved.

Subsequent to the acquisition date, we have adjusted the contingent consideration to fair value with changes in fair value recognized in operating earnings. Changes in fair values reflect new information about the probability and timing of meeting the conditions of the milestone payments. In the absence of new information, changes in fair value will only reflect the interest component of contingent consideration related to changes in the discount rates and the passage of time as development work progresses towards the potential achievement of the milestones. As of December 31, 2020, the fair value of the contingent consideration for the Achillion acquisition was $210.6 based on the probability-weighted cash flows, discounted using a cost of debt ranging from 2.8% to 3.3%. Changes in fair value of the contingent consideration associated with the Achillion acquisition for the year ended December 31, 2020 was $49.9.

The aggregate fair value of equity compensation attributable to the post-combination service period was $25.7. This amount was excluded from the total consideration transferred and was recognized as a charge to acquisition-related costs in our consolidated statements of operations. These amounts were associated with the accelerated vesting of stock options previously granted to Achillion employees. Excluding the $5.7 of contingent consideration related to equity compensation attributable to the post-combination service period, such amounts were paid during the first quarter 2020.

Intangible assets associated with IPR&D relate to two development-stage programs, ACH-4471 (ALXN2040) and ACH-5228 (ALXN2050). The estimated fair value of $918.0 was determined using the excess earnings valuation

method, a variation of the income valuation approach. The excess earnings valuation method estimates the value of an intangible asset equal to the present value of the incremental after-tax cash flows attributable to that intangible asset. Some of the more significant assumptions utilized in our asset valuations included the estimated net cash flows for each asset, including net revenues, cost of sales, research and development and other operating expenses, the potential regulatory and commercial success rates, competitive trends impacting the assets, and tax rates. The fair value using the excess earnings valuation method was determined using an estimated weighted average cost of capital for Achillion of 11.5%, which represents a rate of return that a market participant would expect for these assets. These fair value measurements were based on significant inputs not observable in the market and thus represent Level 3 fair value measurements. In the second quarter 2020, we recognized an impairment charge of $11.0 to write off our ACHN-4471 (ALXN2040) IPR&D asset due to clinical results received during the quarter.

The excess of purchase price over the fair value of the assets acquired and liabilities assumed represents the goodwill resulting from the acquisition. The goodwill, which is not tax-deductible, has been recorded as a noncurrent asset and is not amortized, but is subject to an annual review for impairment. The factors that contributed to the recognition of goodwill include the value of the acquired workforce, synergies that are specific to our business and not available to market participants, and early research in preclinical Factor D inhibitors, as well as the effects of the establishment of a deferred tax liability for the acquired IPR&D intangible assets, which has no tax basis.

We recorded a net deferred tax liability of $62.9, inclusive of measurement period adjustments recorded during the second quarter 2020. This amount was primarily comprised of $205.3 of deferred tax liabilities relating to the IPR&D acquired, offset by $142.4 of deferred tax assets related to net operating loss carryforwards (NOLs), income tax credits, and other temporary differences.

Achillion's results of operations are included in the consolidated financial statements from the date of acquisition. For the year ended December 31, 2020 we recorded $66.8 of pre-tax operating losses exclusive of acquisition-related costs, $49.9 of changes in contingent consideration and $11.0 of impairment charges, associated with the operations of Achillion in our consolidated statements of operations. We also recorded acquisition-related costs in connection with the acquisition for the year ended December 31, 2020 as presented below. No revenues were recorded in the results of operations for the year ended December 31, 2020 as neither ALXN2040 nor ALXN2050 has been approved for commercial sale by any regulatory agency.

Portola Pharmaceuticals, Inc.

In May 2020, Alexion entered into a definitive merger agreement to acquire Portola Pharmaceuticals, Inc. (Portola), a commercial-stage biopharmaceutical company focused on life-threatening blood-related disorders. Portola’s commercialized medicine, ANDEXXA®, marketed as ONDEXXYA® in Europe, is the first and only approved Factor Xa inhibitor reversal agent, and has demonstrated transformative clinical value by rapidly reversing the anticoagulant effects of Factor Xa inhibitors rivaroxaban and apixaban in severe and uncontrolled bleeding. The acquisition provides the opportunity to grow Alexion's commercial portfolio and is a strategic fit with our existing expertise in acute care, hematology and neurology.

Alexion completed the acquisition through a tender offer and subsequent merger of Portola which closed on July 2, 2020. Under the terms of the tender offer and merger agreement, Alexion purchased all outstanding common stock of Portola for $18.00 per share, or an aggregate of approximately $1,380.8, including the settlement of certain of Portola's outstanding equity awards but excluding shares of Portola stock held by Alexion at closing. The acquisition was funded by cash on hand.

Prior to the acquisition of Portola, in March 2020 and April 2020, we purchased $14.5 and $3.6, respectively, of common stock of Portola, which we recorded at fair value. Upon the closing of the acquisition of Portola, the fair value of the equity investment of $47.8 was derecognized and included in the fair value of consideration transferred. For additional information on our Portola equity investment, refer to Note 7, Other Investments.

The aggregate fair value of equity compensation attributable to the post-combination service period was $11.1. This amount was excluded from the total consideration transferred and was recognized as a charge to acquisition-related costs in our consolidated statements of operations. These amounts were primarily associated with the accelerated vesting of stock options previously granted to Portola employees and were paid during the third quarter 2020.

We issued $41.5 of equity compensation replacement awards, of which the portion attributable to services performed prior to the acquisition date, or $7.2, was allocated to purchase consideration. The remaining fair value is attributable to future services and will be expensed as share-based compensation over the remaining service periods. Expense associated with the accelerated-vesting of the replacement awards in connection with employee terminations will be recognized as acquisition-related employee separation costs.

In connection with the acquisition, Alexion also paid $196.9 to settle certain debt held by Portola that was subject to preexisting change of control provisions.

The transaction was accounted for as a business combination. The following table summarizes the total consideration transferred to acquire Portola and the estimated fair value of the identified assets acquired and liabilities assumed at the acquisition date:


Consideration
Upfront payment to shareholders and equity holders	$	1,380.8
Upfront payment, fair value of equity compensation attributable to the post-combination service period	(11.1)
Upfront cash paid, net	1,369.7

Fair value of equity shares held by Alexion at closing	47.8
Fair value of replacement equity awards attributable to the pre-combination period	7.2
Total consideration to acquire outstanding equity, net	1,424.7

Total consideration to settle preexisting debt	196.9
Total consideration	$	1,621.6

Assets Acquired and Liabilities Assumed
Cash and cash equivalents	$	288.5
Marketable securities	17.8
Inventories, including noncurrent portion of $169.1 and validation batches of $60.9	362.5
Intangible assets	1,051.0
Goodwill	24.9
Deferred tax assets, net	116.6
Other assets	41.9
Accounts payable and accrued expenses	(75.6)
Long-term debt, including current portion of $7.7	(182.0)
Other liabilities	(24.0)
Total net assets acquired	$	1,621.6

Our accounting for this acquisition was finalized during the fourth quarter of 2020. Measurement period adjustments decreased goodwill by $0.6 during the fourth quarter of 2020 due to purchase price allocation increases to deferred tax assets, net. Measurement period adjustments were recorded as a result of studies completed during the fourth quarter of 2020 to determine the tax deductibility of certain acquisition-related costs and the valuation of historical net operating loss and income tax credit carryforwards.

We acquired $362.5 of ANDEXXA inventory, inclusive of $60.9 of validation batches manufactured under processes which are subject to regulatory approval and expected to be commercially saleable following approval. The estimated fair value of raw material inventory was valued at replacement cost, which is equal to the value a market participant would pay to acquire the inventory. The estimated fair value of work-in-process and finished goods inventory was based on the expected selling price of the inventory, adjusted for incremental costs to complete the manufacturing process, for direct selling efforts, and for a normal profit on the remaining manufacturing and selling

costs. Additionally, as the inventory acquired, inclusive of validation batches, is expected to be realized over a period of approximately 3 years, the fair value of the inventory was determined using a discount rate of 17.5%, representing the rate of return that a market participant would expect for the inventory, which shares risk that is similar to the underlying intellectual property. These fair value measurements were based on significant inputs not observable in the market and thus represent Level 3 fair value measurements. The acquired inventory, inclusive of the acquisition-date fair value step-up, will be expensed within cost of sales as the inventory is sold to customers. We classified the ANDEXXA inventory that is expected to be utilized beyond our normal operating cycle as a long-term asset. The fair value of the non-current portion of inventory, in addition to the validation batches, are classified within other assets in our consolidated balance sheet.

Intangible assets consist of purchased technology of $1,036.0 and IPR&D of $15.0. The purchased technology intangible asset relates to Portola's lead product ANDEXXA. The estimated fair value was determined using the excess earnings valuation method, a variation of the income valuation approach. The excess earnings valuation method estimates the value of an intangible asset equal to the present value of the incremental after-tax cash flows attributable to that intangible asset. Some of the more significant assumptions utilized in our asset valuation included the estimated net cash flows for ANDEXXA, including net revenues, cost of sales, research and development and other operating expenses, the potential regulatory and commercial success rates associated with ANDEXXA's current conditional approval status and planned extension into the urgent surgery setting, competitive trends impacting the assets, and tax rates. The fair value using the excess earnings valuation method was determined using a discount rate commensurate with the risks of ANDEXXA of 17.5%, which represents a rate of return that a market participant would expect for the asset. The acquired purchased technology intangible asset is being amortized over an estimated useful life of approximately 10 years. IPR&D relates to the cerdulatinib development-stage asset. The estimated fair value of the IPR&D asset was determined using a relief from royalty (RFR) method, a variation of the income approach that is based on the cost savings that accrue to the owner of an intangible asset who would otherwise have to pay royalties on revenues earned through the use of the asset. The RFR method was modified to reflect the cash flow forecast of Portola's pre-existing in-license of cerdulatinib from Astellas Pharma, Inc. The acquired fair value of $15.0 represents an increase in the value of the asset relative to when it was initially in-licensed by Portola. Some of the more significant assumptions utilized in the IPR&D asset valuation included the estimated net revenue, royalty rate, and tax rates. The fair value using the RFR method was determined using an estimated discount rate commensurate with the risks of cerdulatinib of 17.5%, which represents a rate of return that a market participant would expect for the asset. These fair value measurements were based on significant inputs not observable in the market and thus represent Level 3 fair value measurements.

In connection with the acquisition, we assumed royalty-based debt which requires repayment through tiered royalties on future net worldwide sales of ANDEXXA. Total potential royalty payments are capped at $290.6, of which $13.7 were paid by Portola prior to the acquisition. The fair value of the remaining $276.9 in royalty-based payments as of the date of acquisition was $182.0. The estimated fair value was measured using Level 3 inputs and was calculated using a real options method, which runs simulations using various estimates, including probability-weighted net sales of ANDEXXA and volatility. Using the simulation results, the fair value was calculated based on the expected probability-weighted risk-neutral royalties, discounted at our estimated cost of debt, ranging from 3.3% to 7.1%, commensurate with the cost of debt at each period in which the royalty-based payments are estimated to be made.

We recorded net deferred tax assets of $116.6, inclusive of measurement period adjustments recorded during the fourth quarter 2020. This amount was primarily comprised of $301.6, $41.8, $42.4 and $39.3 of deferred tax assets relating to net operating loss carryforwards (NOLs), income tax credits, royalty-based debt, and other temporary differences, respectively, offset by $245.1 and $63.4 of deferred tax liabilities relating to intangible assets acquired and inventory fair value adjustments, respectively.

The excess of purchase price over the fair value of the assets acquired and liabilities assumed represents the goodwill resulting from the acquisition. The goodwill, which is not tax-deductible, has been recorded as a noncurrent asset and is not amortized, but is subject to an annual review for impairment. The factors that contributed to the recognition of goodwill primarily include the value of the acquired workforce and the effects of the establishment of a deferred tax liability for the fair value step-up of acquired inventory and intangible assets which exceed the incremental book value of acquired deferred tax assets over their fair value.

Portola's results of operations are included in the consolidated financial statements from the date of acquisition. For the year ended December 31, 2020, we recorded $78.8 of revenue primarily associated with

ANDEXXA in our consolidated statements of operations. For the year ended December 31, 2020, we recorded $80.5 of pre-tax operating losses excluding acquisition-related costs and $51.8 of intangible asset amortization, associated with the operations of Portola in our consolidated statements of operations. We also recorded acquisition-related costs in connection with the acquisition during the year ended December 31, 2020 as presented below.

Pro forma financial information (unaudited)

The following unaudited pro forma information presents the combined results of Alexion, Achillion, and Portola as if the acquisitions of Achillion and Portola had been completed on January 1, 2019, with adjustments to give effect to pro forma events that are directly attributable to the acquisitions. The unaudited pro forma results do not reflect operating efficiencies or potential cost savings that may have resulted from the consolidation of operations. Accordingly, the unaudited pro forma financial information is not necessarily indicative of the results of operations had we completed the transaction on January 1, 2019.


	Year ended December 31,
	2020		2019
Pro forma revenue	$	6,118.3	$	5,107.7
Pro forma net income	$	519.9	$	1,813.6

The unaudited pro forma consolidated results for the years ended December 31, 2020 and 2019 primarily include the following pro forma adjustments related to non-recurring activity, net of tax:

•Reclassification of Alexion, Achillion and Portola acquisition-related costs. Acquisition-related costs of $150.8 were excluded from net income for the year ended December 31, 2020. Expenses of $136.4 were included in net income for the year ended December 31, 2019.

•Incremental amortization expense related to Portola purchased technology intangible assets for the year ended December 31, 2020 was $39.8 and for the year ended December 31, 2019 was $79.5.

•Incremental cost of goods sold related to Portola inventory fair value step-up adjustments calculated based on the fair value of finished goods inventory for the year ended December 31, 2020 was $11.0 and for the year ended December 31, 2019 was $24.4.

Acquisition-Related Costs

Acquisition-related costs recorded within the consolidated statement of operations associated with our acquisitions of Achillion and Portola and our definitive merger agreement with AstraZeneca for the years ended December 31, 2020, 2019 and 2018 include the following:


	Year ended December 31,
	2020		2019		2018
Transaction costs (1)	$	9.9	$	—	$	—
Integration costs	13.0		—		—
Fair value of equity compensation attributable to the post-combination service period	36.8		—		—
Employee separation costs (2)	57.9		—		—
	$	117.6	$	—	$	—

(1) Transaction costs primarily include legal fees related to the acquisition of Portola as well as costs incurred to effectuate the settlement of the Achillion outstanding options

(2) Employee separation costs include liabilities recognized, and subsequent changes in estimates recorded for, severance payments, one-time short-term retention awards agreed to in connection with the acquisition of Achillion and share-based compensation expense relating to awards accelerated in connection with terminations of Portola employees.

Acquisition-related costs attributable to the Achillion acquisition for the year ended December 31, 2020 were $38.1. Acquisition-related costs attributable to the Portola acquisition for the year ended December 31, 2020 were $77.5. Acquisition-related costs attributable to the Merger Agreement with AstraZeneca for the year ended December 31, 2020 were $2.0.

Asset Acquisitions

Wilson Therapeutics AB

On May 25, 2018, we completed the acquisition of Wilson Therapeutics AB (publ), a biopharmaceutical company based in Stockholm, Sweden (Wilson Therapeutics) that developed a novel therapy for patients with rare copper-mediated disorders, pursuant to a recommended public cash offer of SEK 232 for each share of stock of Wilson Therapeutics. As a result of the acquisition, we added WTX101 (ALXN1840), a highly innovative drug candidate that is currently in Phase III clinical trials for the treatment of patients with Wilson disease, to our clinical pipeline.

The acquisition of Wilson Therapeutics was accounted for as an asset acquisition, as substantially all of the fair value of the gross assets acquired was concentrated in a single asset, WTX101.

The following table summarizes the total consideration for the acquisition and the value of assets acquired and liabilities assumed:


Consideration
Cash paid for acquisition of Wilson Therapeutics outstanding shares	$	749.3
Transaction costs	15.1
Total consideration	$	764.4

Assets Acquired and Liabilities Assumed
Cash	$	45.1
In-process research & development	803.7
Employee related liabilities	(71.4)
Other assets and liabilities	(13.0)
Total net assets acquired	$	764.4

The acquired in-process research and development asset relates to WTX101. Due to the stage of development of this asset at the date of acquisition, significant risk remained and it was not yet probable that there was future economic benefit from this asset. Absent successful clinical results and regulatory approval for the asset, there was no alternative future use associated with WTX101. Accordingly, the value of this asset was expensed during the second quarter of 2018.

Employee related liabilities include the value of outstanding employee equity incentive awards that were accelerated in connection with the Wilson Therapeutics acquisition that have been settled in cash. Also included in this amount were employer tax obligations associated with the employee equity incentive awards.

In connection with rights to WTX101 that were previously acquired by Wilson Therapeutics from third parties, we could be required to pay up to approximately $19.0 if certain development, regulatory and commercial milestones are met over time, as well as royalties on commercial sales.

Syntimmune, Inc.

In September 2018, we entered into a definitive agreement to acquire Syntimmune, Inc. (Syntimmune), a clinical-stage biotechnology company developing an antibody therapy targeting the FcRn. Syntimmune’s lead candidate, SYNT001 (ALXN1830), is a monoclonal antibody that is designed to inhibit the interaction of FcRn with Immunoglobulin G (IgG) and IgG immune complexes, that is being studied for the treatment of IgG-mediated autoimmune diseases. The acquisition of Syntimmune closed in November 2018. Under the terms of the acquisition agreement, Alexion acquired Syntimmune for an upfront cash payment of $400.0, with the potential for additional milestone-dependent payments of up to $800.0, for a total potential value of up to $1,200.0.

The acquisition of Syntimmune was accounted for as an asset acquisition, as substantially all of the fair value of the gross assets acquired was concentrated in a single in-process research and development asset, SYNT001.

In connection with the agreement of the final working capital adjustment for the Syntimmune acquisition, we recognized a benefit of $4.1 associated with previously acquired in-process research and development in the second quarter 2019.

The following table summarizes the total consideration for the acquisition and the value of the assets acquired and liabilities assumed:


Consideration
Upfront payment for acquisition of Syntimmune outstanding shares	$	400.0
Cash acquired	4.2
Working capital adjustment	2.3
Transaction costs	0.9
Total consideration	$	407.4

Assets Acquired and Liabilities Assumed
Cash	$	4.2
In-process research & development	375.2
Deferred tax assets	25.1
Other assets and liabilities	2.9
Total net assets acquired	$	407.4

The acquired in-process research and development asset relates to SYNT001. Due to the stage of development of this asset at the date of acquisition, significant risk remained and it was not yet probable that there was future economic benefit from this asset. Absent successful clinical results and regulatory approval for the asset, there was no alternative future use associated with SYNT001. Accordingly, the value of this asset was expensed during the fourth quarter of 2018.

Property, Plant and Equipment, Net

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment, Net [Abstract]

Property, Plant and Equipment, Net

A summary of property, plant and equipment is as follows:


	December 31, 2020		December 31, 2019
Land	$	9.6	$	9.6
Buildings and improvements	216.7		208.7
Machinery and laboratory equipment	134.1		126.0
Computer hardware and software	171.9		155.1
Furniture and office equipment	24.9		23.4
Construction-in-progress	828.7		734.2
Financing lease right of use assets	127.2		127.2
	1,513.1		1,384.2
Less: Accumulated depreciation and amortization	(274.3)		(220.9)
	$	1,238.8	$	1,163.3

Depreciation and amortization of property, plant and equipment was $56.3, $56.8 and $77.9 recorded within our consolidated statement of operations for the years ended December 31, 2020, 2019 and 2018, respectively. Included within this amount for the year ended December 31, 2018 were charges related to the 2017 restructuring activities. Refer to Note 17, Restructuring and Related Expenses for additional information.

As of December 31, 2020 and 2019, computer software costs included in property, plant and equipment were $53.1 and $53.4, respectively, net of accumulated amortization of $87.7 and $72.9, respectively. Depreciation and amortization expense for capitalized computer software costs was $16.4, $15.3 and $17.4 for the years ended December 31, 2020, 2019 and 2018, respectively.

Intangible Assets and Goodwill

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets and Goodwill

The following table summarizes the carrying amount of our intangible assets and goodwill, net of accumulated amortization:


		December 31, 2020							December 31, 2019
	Estimated Life (years)	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization		Net
Licensing Rights	3-8	$	57.0	$	(38.5)		$	18.5	$	57.0	$	(34.7)	$	22.3
Patents	7	10.5		(10.5)			—		10.5		(10.5)		—
Purchased technology	6-16	5,746.5		(3,684.7)		(a)	2,061.8		4,710.5		(1,388.7)		3,321.8
Other Intangibles	5	0.4		(0.3)			0.1		0.4		(0.2)		0.2
Acquired IPR&D	Indefinite	922.0		—			922.0		—		—		—
Total		$	6,736.4	$	(3,734.0)		$	3,002.4	$	4,778.4	$	(1,434.1)	$	3,344.3
Goodwill	Indefinite	$	5,103.0	$	(2.9)		$	5,100.1	$	5,040.3	$	(2.9)	$	5,037.4
(a) Includes an impairment charge of $2,042.3 recognized during the second quarter related to the KANUMA intangible asset

In connection with our acquisition of Achillion during the first quarter 2020, we acquired IPR&D programs with a fair value of $918.0 and recorded goodwill of $37.8. For additional information on our acquisition of Achillion, refer to Note 2, Acquisitions. In the second quarter 2020, we recognized an impairment charge of $11.0 to write off the cost basis of our ACHN-4471 (ALXN2040) acquired in-process research and development asset due to clinical results received during the quarter.

In connection with our acquisition of Portola during the third quarter 2020, we acquired purchased technology and IPR&D programs with a fair value of $1,036.0 and $15.0, respectively and recorded goodwill of $24.9. For additional information on our acquisition of Portola, refer to Note 2, Acquisitions.

During the year ended December 31, 2019 we capitalized $18.0 related to regulatory approval and commercial milestones related to in-licensing arrangements.

Amortization expense was $257.6, $315.0 and $321.1 for the years ended December 31, 2020, 2019 and 2018, respectively. Assuming no changes in the gross cost basis of intangible assets, the total estimated amortization expense for finite-lived intangible assets is approximately $216.0 for each of the years ending December 31, 2021 through December 31, 2025.

During the quarter ended June 30, 2020, based on continued challenges expanding patient growth and new alternative commercial opportunities, we revised our strategic view of KANUMA and determined that we have exhausted commercially viable initiatives related to KANUMA and will have difficulty expanding patient growth over the long term as we focus on promoting other commercial programs and growing our pipeline. As a result, we no longer expect to increase the number of KANUMA patients in the long term at the rate previously assumed. This determination resulted in reduced cash flow projections for KANUMA, which indicated that the related intangible asset value was not fully recoverable on an undiscounted cash flows basis. As of June 30, 2020, we utilized market participant assumptions to determine its best estimate of the fair value of the intangible asset related to KANUMA that, when compared with its related carrying value, resulted in an impairment charge of $2,042.3.

The estimated fair value of the KANUMA asset as of June 30, 2020 was determined using the excess earnings method, a variation of the income approach. The excess earnings method estimates the value of an intangible asset equal to the present value of the incremental after-tax cash flows attributable to that intangible asset over its remaining economic life. Long term cash flow projections for the asset require the use of significant estimates and judgements, including forecasted revenue growth rates, forecasted cost of goods sold and the discount rate, and were based on our most recent strategic plan. The fair value of the asset was determined using an estimated weighted average cost of capital of 10.0%, which reflects the risks inherent in future cash flow projections and represents a rate of return that a market participant would expect for this asset. The estimated revenue growth rates fluctuate over the life of the asset, with a weighted average growth rate in the low single digits. We believe our assumptions are consistent with the plans and estimates that a market participant would use to manage the business. The estimated fair value of the KANUMA intangible asset as of June 30, 2020 was $820.0 and will continue to be amortized over its remaining estimated useful life. This fair value measurement was based on

significant inputs not observable in the market and thus represents a Level 3 fair value measurement. The carrying value of the KANUMA intangible asset as of December 31, 2020 was $782.7.

The following summarizes the changes in the carrying amount of goodwill:


	December 31, 2020
Balance as of December 31, 2019	$	5,037.4
Goodwill resulting from the acquisitions of Achillion and Portola	62.7
Balance as of December 31, 2020	$	5,100.1

Marketable Securities

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

The proceeds from maturities and sales of available-for-sale debt securities and resulting realized gains and losses are summarized below. In the second quarter of 2020, we liquidated all of our available-for-sale debt securities to fund the acquisition of Portola. Additionally, we liquidated all available-for-sale debt securities acquired in connection with the Portola acquisition.


	Year ended December 31,
	2020		2019		2018
Proceeds from maturities and sales (1)	$	1,042.5	$	2,832.8	$	10,196.8
Realized gains	$	—	$	—	$	1.1
Realized losses	$	—	$	—	$	0.4
(1) Proceeds from maturities and sales of available-for-sale debt securities include securities previously classified as cash and cash equivalents and marketable securities in the consolidated balance sheet

We utilize the specific identification method in computing realized gains and losses.

As a result of our liquidation of all available-for-sale debt securities during the second quarter 2020, we have no remaining available-for-sale debt securities as of December 31, 2020. The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security as of December 31, 2019 were as follows:


	December 31, 2019
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
Commercial paper	$	246.9	$	—	$	—	$	246.9
Corporate bonds	24.3		—		—		24.3
Other government related obligations:
U.S.	70.4		—		—		70.4
Bank certificates of deposit	27.4		—		—		27.4
Total available-for-sale debt securities	$	369.0	$	—	$	—	$	369.0

The aggregate fair value of available-for-sale debt securities in an unrealized loss position as of December 31, 2019 was $21.5. We did not have any investments in a continuous unrealized loss position for more than twelve months as of December 31, 2019.

The fair values of available-for-sale debt securities by classification in the consolidated balance sheet were as follows:


	December 31, 2020		December 31, 2019
Cash and cash equivalents	$	—	$	328.1
Marketable securities	—		40.9
	$	—	$	369.0

We sponsor a nonqualified deferred compensation plan which allows certain highly-compensated employees to make voluntary deferrals of up to 80% of their base salary and incentive bonuses. The plan is designed to work in conjunction with the 401(k) plan and provides for a total combined employer match of up to 6% of an employee’s eligible earnings, up to the IRS annual 401(k) contribution limitations. Participants in the plan earn a return on their deferrals based on several investment options, which mirror returns on underlying mutual fund investments. We choose to invest in the underlying mutual fund investments to offset the liability associated with our nonqualified deferred compensation plan. These mutual fund investments are valued at net asset value per share and are carried at fair value with gains and losses included in investment income. The changes in the underlying liability to the employee are recorded in operating expenses. As of December 31, 2020 and December 31, 2019, the fair value of these investments was $34.9 and $23.1, respectively. Employer matching contributions under the plan for the years ended December 31, 2020, 2019 and 2018 were not material.

Derivative Instruments and Hedging Activities

12 Months Ended

Dec. 31, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Instruments and Hedging Activities

We operate internationally and, in the normal course of business, are exposed to fluctuations in foreign currency exchange rates. The exposures result from portions of our revenues, as well as the related receivables, and expenses that are denominated in currencies other than the U.S. dollar, primarily the Euro and Japanese Yen. We are also exposed to fluctuations in interest rates on outstanding borrowings under our revolving credit facility, if any, and term loan facility. We manage these exposures within specified guidelines through the use of derivatives. All of our derivative instruments are utilized for risk management purposes, and we do not use derivatives for speculative trading purposes.

We enter into foreign exchange forward contracts to hedge exposures resulting from portions of our forecasted revenues, including intercompany revenues, and certain forecasted expenses that are denominated in currencies other than the U.S. dollar. Revenue and expense related foreign exchange forward contracts in effect as of December 31, 2020 had durations of up to 23 months and 60 months, respectively. The purpose of these hedges is to reduce the volatility of exchange rate fluctuations on our operating results. These hedges are designated as cash flow hedges upon contract inception. As of December 31, 2020, we had open revenue related foreign exchange forward contracts with notional amounts totaling $1,174.7 that qualified for hedge accounting with current contract maturities through June 2022. As of December 31, 2020, we had open expense related foreign exchange forward contracts with notional amounts totaling $8.7 that qualified for hedge accounting with contract maturities through September 2022.

To achieve a desired mix of floating and fixed interest rates on our term loan, we enter into interest rate swap agreements that qualify for and are designated as cash flow hedges. These contracts convert the floating interest rate on a portion of our debt to a fixed rate, plus a borrowing spread.

The following table summarizes the total interest rate swap contracts executed as of December 31, 2020:

Type of Interest Rate Swap

Notional Amount

Effective Date

Termination Date

Fixed Interest Rate or Rate Range

Floating to Fixed

$450.0

December 2018

December 2022

2.60% - 2.79%

Floating to Fixed

$1,300.0

December 2019

December 2022

2.37% - 2.83%

The amount of gains and (losses) recognized in the consolidated statements of operations for the years ended December 31, 2020, 2019 and 2018 from foreign exchange and interest rate swap contracts that qualified as cash flow hedges were as follows:


	Year ended December 31,
	2020				2019				2018
Financial Statement Line Item in which the Effects of Cash Flow Hedges are Recorded	Net Product Sales		Interest Expense		Net Product Sales		Interest Expense		Net Product Sales		Interest Expense
Total amount presented in the Consolidated Statements of Operations	$	6,069.1	$	(104.7)	$	4,990.0	$	(77.8)	$	4,130.1	$	(98.2)
Impact of cash flow hedging relationships:
Foreign exchange forward contracts	$	4.7	$	—	$	36.8	$	—	$	(1.8)	$	—
Interest rate swap contracts	$	—	$	(37.5)	$	—	$	13.3	$	—	$	13.6

The impact on accumulated other comprehensive income (AOCI) and earnings from foreign exchange and interest rate swap contracts that qualified as cash flow hedges, for the years ended December 31, 2020, 2019, and 2018 were as follows:


	Year Ended December 31,
	2020		2019		2018
Foreign Exchange Forward Contracts:
(Loss) gain recognized in AOCI, net of tax	$	(36.4)	$	27.9	$	37.7
Gain (loss) reclassified from AOCI to net product sales, net of tax	$	3.6	$	28.4	$	(1.4)
Interest Rate Swap Contracts:
Loss recognized in AOCI, net of tax	$	(52.3)	$	(39.0)	$	(4.8)
(Loss) gain reclassified from AOCI to interest expense, net of tax	$	(29.1)	$	10.2	$	10.8

Assuming no change in foreign exchange rates from market rates at December 31, 2020, $44.2 of losses recognized in AOCI will be reclassified to revenue over the next 12 months. Assuming no change in LIBOR-based interest rates from market rates at December 31, 2020, $45.9 of losses recognized in AOCI will be reclassified to interest expense over the next 12 months. Amounts recognized in AOCI for expense related foreign exchange forward contracts were immaterial as of December 31, 2020.

We enter into foreign exchange forward contracts designed to limit the balance sheet exposure of monetary assets and liabilities. We enter into these hedges to reduce the impact of fluctuating exchange rates on our operating results. Balance sheet hedges related foreign exchange forward contracts in effect as of December 31, 2020 had durations of up to 6 months. Hedge accounting is not applied to these derivative instruments as gains and losses on these hedge transactions are designed to offset gains and losses on underlying balance sheet exposures. As of December 31, 2020, the notional amount of foreign exchange contracts where hedge accounting is not applied was $2,070.1.

We recognized a (loss) gain of $(3.6), $(0.4) and $23.0, in other income and (expense) for the years ended December 31, 2020, 2019 and 2018, respectively, associated with the foreign exchange contracts not designated as hedging instruments. These amounts were partially offset by gains or losses on monetary assets and liabilities.

The following tables summarize the fair value of outstanding derivatives as of December 31, 2020 and 2019:

December 31, 2020

Asset Derivatives

Liability Derivatives

Balance Sheet
Location

Fair
Value

Balance Sheet
Location

Fair
Value

Derivatives designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

—

Other current liabilities

44.3

Foreign exchange forward contracts

Other assets

—

Other liabilities

1.2

Interest rate contracts

Prepaid expenses and other current assets

—

Other current liabilities

45.9

Interest rate contracts

Other assets

—

Other liabilities

45.4

Derivatives not designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

26.1

Other current liabilities

35.8

Total fair value of derivative instruments

26.1

172.6

December 31, 2019

Asset Derivatives

Liability Derivatives

Balance Sheet
Location

Fair
Value

Balance Sheet
Location

Fair
Value

Derivatives designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

12.7

Other current liabilities

6.2

Foreign exchange forward contracts

Other assets

0.6

Other liabilities

1.1

Interest rate contracts

Prepaid expenses and other current assets

—

Other current liabilities

19.5

Interest rate contracts

Other assets

—

Other liabilities

41.9

Derivatives not designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

17.2

Other current liabilities

20.4

Total fair value of derivative instruments

30.5

89.1

Although we do not offset derivative assets and liabilities within our consolidated balance sheets, our International Swap and Derivatives Association agreements provide for net settlement of transactions that are due to or from the same counterparty upon early termination of the agreement due to an event of default or other termination event. The following tables summarize the potential effect on our consolidated balance sheets of offsetting our foreign exchange forward contracts and interest rate contracts subject to such provisions:


December 31, 2020
							Gross Amounts Not Offset in the Consolidated Balance Sheet
Description	Gross Amounts of Recognized Assets/Liabilities		Gross Amounts Offset in the Consolidated Balance Sheet		Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheet		Derivative Financial Instruments		Cash Collateral Received (Pledged)		Net Amount
Derivative assets	$	26.1	$	—	$	26.1	$	(26.1)	$	—	$	—
Derivative liabilities	$	(172.6)	$	—	$	(172.6)	$	26.1	$	—	$	(146.5)


December 31, 2019
							Gross Amounts Not Offset in the Consolidated Balance Sheet
Description	Gross Amounts of Recognized Assets/Liabilities		Gross Amounts Offset in the Consolidated Balance Sheet		Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheet		Derivative Financial Instruments		Cash Collateral Received (Pledged)		Net Amount
Derivative assets	$	30.5	$	—	$	30.5	$	(21.4)	$	—	$	9.1
Derivative liabilities	$	(89.1)	$	—	$	(89.1)	$	21.4	$	—	$	(67.7)

Other Investments	12 Months Ended
Other Investments	Dec. 31, 2020
Investments, All Other Investments [Abstract]
Other Investments	Other Investments Other investments include strategic investments in equity securities of certain biotechnology companies which we acquired in connection with strategic business development transactions, including license and option agreements. These investments are included in other assets in our consolidated balance sheets. Moderna During 2014, we purchased $37.5 of preferred stock of Moderna Therapeutics, Inc. (Moderna), a privately held biotechnology company, which was recorded at cost. During the first quarter 2018, Moderna announced the completion of a new round of financing. We considered this transaction and the rights of the new shares issued in the new round, compared to the rights of the preferred equity that we held, and concluded that Moderna’s new round of financing represented an observable price change in an orderly transaction for a similar investment. We further concluded, based on the respective rights of the stock and consideration of potential liquidity events, that the value of our preferred stock was equivalent to the value of the newly issued preferred stock. As a result, we recognized an unrealized gain of $100.8 in investment income during the first quarter 2018 to adjust our equity investment in Moderna to fair value as of the date of the observable price change, based on the per share price in Moderna's new round of financing. On December 6, 2018, Moderna completed its initial public offering (IPO) and shares of Moderna began trading on the Nasdaq Global Select Market under the symbol “MRNA.” As part of the IPO, our preferred stock was converted into Moderna common stock and subject to a one year lock-up period. As our equity investment in Moderna common stock now had a readily determinable fair value, we began to record the investment at fair value, with the effects of the holding period restriction estimated using an option pricing valuation model. During the fourth quarter 2018, we recognized an unrealized loss of $56.4 in investment income to adjust our investment in Moderna to fair value as of December 31, 2018. On December 9, 2019, we sold our investment in Moderna. We received $114.7 in net proceeds, resulting in a realized gain of $77.2 on our initial investment. During the year ended December 31, 2019, we recognized a gain of $32.8 in investment income. Dicerna In October 2018, we purchased $10.3 of Dicerna Pharmaceuticals Inc. (Dicerna) common stock in connection with an agreement that we entered into with Dicerna, a publicly-traded biopharmaceutical company. As our equity investment in Dicerna common stock has a readily determinable fair value, we are recording the investment at fair value. During the year ended December 31, 2020, there was no unrealized gain or loss recognized in investment income as the fair value of the common stock as of December 31, 2020 was consistent with the fair value as of December 31, 2019. During the years ended December 31, 2019 and 2018, we recognized an unrealized gain of $9.5 and an unrealized loss of $1.4, respectively, in investment income to adjust our equity investment in Dicerna to fair value. The fair value of this investment was $18.4 as of December 31, 2020 and 2019. Caelum In January 2019, we purchased $41.0 of preferred stock of Caelum Biosciences (Caelum), a privately-held biotechnology company, and a $16.1 option to acquire the remaining equity in Caelum, based on Phase II data, in connection with an agreement that we entered into with Caelum. Following discussions with the FDA, Caelum changed its clinical development plan for CAEL-101 in the fourth quarter 2019. In December 2019, we amended the terms of the agreement with respect to the option to acquire the remaining equity in Caelum based on data from the modified Phase II/III trials. We accounted for the amendment as an exchange transaction as the terms of the modified option were determined to be substantially different than the terms of the original option. In conjunction with this amendment, we recognized a gain of $32.0 during the fourth quarter 2019 in other income and (expense), which reflects an increase in the fair value of the option, less $20.0 in incremental upfront funding which we accrued as of December 31, 2019 and paid during the first quarter 2020, and $4.1 associated with the change in the fair value of contingent payments which we also modified as part of the amendment. Refer to Note 11, Commitments and Contingencies, for additional information on the agreement. As our equity investment in Caelum and the option to acquire the remaining equity in Caelum does not have a readily determinable fair value, we only adjust the carrying value of the assets for impairment and any subsequent changes resulting from an observable price change in an orderly transaction for identical or similar equity securities of the same issuer. There were no observable price changes associated with these assets during the year ended December 31, 2020 and 2019. A Phase II trial for CAEL-101 commenced during the first quarter of 2020 and met its primary objectives, supporting the safety and tolerability of CAEL-101 and confirmed the dose and regimen to be adopted for the Phase III studies. In September 2020, Alexion and Caelum announced the initiation of the Cardiac Amyloid Reaching for Extended Survival (CARES) program. This includes two parallel Phase III trials to evaluate the survival benefits of CAEL-101. In December 2020, in connection with entering into the Merger Agreement with AstraZeneca (refer to Note 1, Business Overview and Summary of Significant Accounting Policies), we determined that the fair value of our option to acquire the remaining equity of Caelum decreased as a result of a change to the expected option exercise date. This resulted in a $49.0 impairment charge which we recorded to investment income, net. The carrying value of the preferred stock was unaffected. As of December 31, 2020, the carrying value of the investment and option, respectively, was $41.0 and $15.0. As of December 31, 2019, the carrying value of the investment and option, respectively, was $41.0 and $64.0. Zealand In March 2019, we purchased $13.8 (Kr. 90.9) of Zealand Pharma A/S (Zealand) common stock in connection with an agreement that we entered into with Zealand, a publicly-traded biopharmaceutical company based in Copenhagen, Denmark. Refer to Note 11, Commitments and Contingencies for additional information on the agreement. As our equity investment in Zealand common stock has a readily determinable fair value, we are recording the investment at fair value. During the years ended December 31, 2020 and 2019, we recognized an unrealized loss of $1.9 and an unrealized gain of $14.7, respectively, in investment income to adjust our equity investment in Zealand to fair value. The fair value of this investment was $29.1 and $28.5 as of December 31, 2020 and 2019, respectively. Eidos In September 2019, we purchased $19.9 of Eidos Therapeutics, Inc. (Eidos) common stock, in connection with an agreement that we entered into with Eidos, a publicly-traded biopharmaceutical company and subsidiary of BridgeBio Pharma, Inc. Refer to Note 11, Commitments and Contingencies, for additional information on the agreement. As our equity investment in Eidos common stock has a readily determinable fair value, we are recording the investment at fair value. During the years ended December 31, 2020 and 2019, we recognized an unrealized gain of $45.4 and $7.9, respectively, in investment income to adjust our equity investment in Eidos to fair value. The fair value of this investment was $73.2 and $27.8 as of December 31, 2020 and 2019, respectively. Stealth In October 2019, we purchased $9.6 of Stealth BioTherapeutics Corp. (Stealth) common stock, in connection with an agreement that we entered into with Stealth, a publicly traded clinical-stage biotechnology company. As our equity investment in Stealth common stock has a readily determinable fair value, we are recording the investment at fair value. During the years ended December 31, 2020 and 2019, we recognized an unrealized loss of $2.4 and $5.2, respectively, in investment income to adjust our equity investment in Stealth to fair value. The fair value of this investment was $2.0 and $4.4 as of December 31, 2020 and 2019, respectively. Portola In March 2020 and April 2020, we purchased $14.5 and $3.6, respectively, of common stock of Portola Pharmaceuticals, Inc., a publicly traded commercial-stage biological company which we acquired on July 2, 2020. As our equity investment in Portola common stock had a readily determinable fair value, we recorded the investment at fair value. Upon the closing of the acquisition of Portola on July 2, 2020, the fair value of the equity investment of $47.8 was derecognized and included in the fair value of consideration transferred, resulting in a realized gain of $29.7 in investment income on our initial investment. Refer to Note 2, Acquisitions, for additional information. Inozyme On July 17, 2020, we sold certain intellectual property rights and assets focusing on ENPP1 gene deficiencies to Inozyme Pharma (Inozyme), a publicly traded biopharmaceutical company, in exchange for $14.8 of Inozyme Pharma common stock, which was initially recorded at its IPO offering price, net of the effects of a nine month holding period restriction. We recognized the $14.8 of consideration received as a gain within gain on sale of asset in our consolidated statement of operations. As our equity investment in Inozyme common stock has a readily determinable fair value, we are recording the investment at fair value, with the effects of a nine month holding period restriction estimated using an option pricing valuation model. During the year ended December 31, 2020, we recognized an unrealized gain of $5.7 in investment income to adjust our equity investment in Inozyme to fair value. The fair value of this investment was $20.5 as of December 31, 2020.

Accounts Payable and Accrued Expenses

12 Months Ended

Dec. 31, 2020

Accrued Liabilities [Abstract]

Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist of the following:


	December 31, 2020		December 31, 2019
Accounts payable	$	118.6	$	74.0
Royalties	27.6		20.1
Payroll and employee benefits	242.3		187.5
Taxes payable	150.9		103.9
Rebates payable	333.3		250.1
Clinical	97.0		67.3
Manufacturing	58.2		72.8
Accrued severance and restructuring costs	31.7		12.8
Other	143.7		178.2
	$	1,203.3	$	966.7

Debt

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Debt

Credit Agreement

On June 7, 2018, we entered into an Amended and Restated Credit Agreement (the Credit Agreement), with Bank of America, N.A. as Administrative Agent. The Credit Agreement amended and restated our credit agreement dated as of June 22, 2015 (the Prior Credit Agreement).

The Credit Agreement provides for a $1,000.0 revolving credit facility and a $2,612.5 term loan facility. The revolving credit facility and the term loan facility mature on June 7, 2023. Beginning with the quarter ended June 30, 2019, we are required to make payments of 5.0% of the original principal amount of the term loan facility annually, payable in equal quarterly installments.

Loans under the Credit Agreement bear interest, at our option, at either a base rate or a Eurodollar rate, in each case plus an applicable margin. Under the Credit Agreement, the applicable margins on base rate loans range from 0.25% to 1.00% and the applicable margins on Eurodollar loans range from 1.25% to 2.00%, in each case based on our consolidated net leverage ratio (as calculated in accordance with the Credit Agreement). As of December 31, 2020, the interest rate on our outstanding loans under the Credit Agreement was 1.4%. Our obligations under the Credit Agreement are guaranteed by certain of Alexion Pharmaceuticals, Inc.'s foreign and domestic subsidiaries and secured by liens on certain of our subsidiaries’ equity interests, subject to certain exceptions. Under the terms of the Credit Agreement, we must maintain a ratio of total net debt to EBITDA of 3.50 to 1.00 (subject to certain limited adjustments) and EBITDA to cash interest expense ratio of at least 3.50 to 1.00, in each case as calculated in accordance with the Credit Agreement. We were in compliance with all applicable covenants under the Credit Agreement as of December 31, 2020.

The Credit Agreement contains certain representations and warranties, affirmative and negative covenants and events of default. The negative covenants in the Credit Agreement restrict Alexion’s and its subsidiaries’ ability, subject to certain baskets and exceptions, to (among other things) incur liens or indebtedness, make investments, enter into mergers and other fundamental changes, make dispositions or pay dividends. The restriction on dividend payments includes an exception that permits us to pay dividends and make other restricted payments regardless of dollar amount so long as, after giving pro forma effect thereto, we have a consolidated net leverage ratio, as defined in the Credit Agreement, within predefined ranges, subject to certain increases following designated material acquisitions.

In connection with entering into the Credit Agreement and the Prior Credit Agreement, we paid an aggregate of $53.1 in financing costs in 2018. Financing costs are amortized as interest expense over the life of the debt. Amortization expense associated with deferred financing costs for the years ended December 31, 2020, 2019, and

2018 was $4.7, $5.0 and $8.0, respectively. Remaining unamortized deferred financing costs as of December 31, 2020 and 2019 were $11.1 and $15.8, respectively.

We made principal payments of $130.6 on the term loan during 2020 and as of December 31, 2020, we had $2,383.9 outstanding on the term loan. We made principal payments of $98.0 on the term loan during 2019 and as of December 31, 2019, we had $2,514.5 outstanding on the term loan. We had no outstanding borrowings under the revolving credit facility during the years ended December 31, 2020 and 2019. As of December 31, 2020 and 2019, we had open letters of credit of $1.0 that offset our availability in the revolving facility.

The amount outstanding under the term loan of $2,383.9 as of December 31, 2020 is subject to variable interest rates, which are based on current market rates, and as such, the Company believes the carrying amount of the obligation approximates fair value.

In connection with the planned merger with AstraZeneca, we evaluated the terms of the Credit Agreement and determined that the agreement could require acceleration of payments upon a change of control.

Royalty-based Financing

In connection with our acquisition of Portola during the third quarter 2020, we assumed royalty-based debt relating to a royalty sales agreement Portola had entered into with HealthCare Royalty Partners (HCR) whereby HCR acquired a tiered royalty interest in future worldwide net sales of ANDEXXA. Portola received $50.0 upon closing of the agreement in February 2017 and an additional $100.0 following the U.S. regulatory approval of ANDEXXA in May 2018. Tiered royalties ranging from 4.2% to 8.5% are required to be paid to HCR based on net worldwide sales of ANDEXXA. The applicable rate decreases as worldwide net annual sales levels increase above defined thresholds. Total potential royalty payments are capped at 195.0% of the funding received less certain transaction expenses, or $290.6. As of the date of acquisition, the remaining due to HCR was $276.9 in royalty-based payments.

We recorded the HCR debt at its fair value of $182.0 upon closing of the acquisition, representing an initial debt discount of $94.9. We have also recognized a deferred tax asset of $42.4 related to the royalty-based debt as of the acquisition date. For additional information on our acquisition of Portola, refer to Note 2, Acquisitions. Interest expense is recognized using the effective interest rate method over the estimated period the related debt will be paid. This requires estimation of the timing and amount of future royalty payments to be generated from future sales of ANDEXXA. We reassess the expected royalty payments each reporting period and account for any changes through an adjustment to the effective interest rate on a prospective basis. The assumptions used in determining the expected repayment term of the debt require that we make estimates that could impact the short and long term classification of the debt carrying values.

Each period, we amortize the initial debt discount using the effective interest rate implied from the projected timing of royalty payments to HCR. The effective interest rate for the HCR royalty-based debt as of December 31, 2020 was 11.5%. During the year ended December 31, 2020, we recognized interest expense associated with the amortization of the debt discount of $10.0. We made royalty-based debt payments of $5.0 during 2020. As of December 31, 2020, the carrying value of the royalty-based debt includes approximately $3.0 of royalty payments on fourth quarter sales of ANDEXXA which will be paid during the first quarter 2021.

As of December 31, 2020, the carrying value of the HCR royalty-based debt was $187.0, of which $15.5 was recorded within current portion of long-term debt and $171.5 was recorded within long-term debt, less current portion on our consolidated balance sheet. Our payment obligations for HCR royalty-based debt are as follows:


	Year ended December 31, 2020
Total repayment obligation as of the acquisition date	$	276.9
Less: interest to be accreted in future periods	(84.9)
Less: payments made	(5.0)
Carrying value as of December 31, 2020	$	187.0

The carrying value of the royalty-based debt as of December 31, 2020 approximates fair value.

Contractual Maturities:

The contractual maturities of our Credit Agreement and estimated royalty-based debt obligations due subsequent to December 31, 2020 are as follows:


Year
2021	$	146.1
2022	158.4
2023	2,167.7
2024	63.6
2025	76.5
Thereafter	43.5

Leases

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Leases

The following table summarizes our lease assets and liabilities as of December 31, 2020:


ROU Assets and Liabilities
	Balance Sheet Location	Financing		Operating
ROU - Asset	Right of use operating assets	$	—	$	223.1
ROU - Asset	Property, plant, and equipment	105.4		—
Lease liabilities (current)	Other current liabilities	5.6		28.1
Lease liabilities (noncurrent)	Noncurrent operating lease liabilities	—		177.1
Lease liabilities (noncurrent)	Other liabilities	67.3		—

The following table summarizes our lease assets and liabilities as of December 31, 2019:


ROU Assets and Liabilities
	Balance Sheet Location	Financing		Operating
ROU - Asset	Right of use operating assets	$	—	$	204.0
ROU - Asset	Property, plant, and equipment	116.3		—
Lease liabilities (current)	Other current liabilities	5.2		18.8
Lease liabilities (noncurrent)	Noncurrent operating lease liabilities	—		164.1
Lease liabilities (noncurrent)	Other liabilities	72.9		—

The following table summarizes our lease related costs for the years ended December 31, 2020 and 2019:


Lease Cost:
	Statement of Operations Location	Years ended
		December 31, 2020		December 31, 2019
Financing Lease Cost		$	14.5	$	14.8
Amortization of ROU Assets	Operating Expenses	10.9		10.9
Interest on Lease Liabilities	Interest Expense	3.6		3.9
Operating Lease Cost	Operating Expenses	38.1		34.3
Variable Lease Cost	Operating Expenses	8.7		11.8
Total Lease Cost		$	61.3	$	60.9

Amounts above include $11.9 and $15.6, of lease costs associated with our CMO embedded lease arrangement for the years ended December 31, 2020 and 2019, respectively, which have been capitalized as part of the cost of product being manufactured at the site.

The following table summarizes supplemental cash flow information for the years ended December 31, 2020 and 2019:


Other Information
	Years ended
	December 31, 2020		December 31, 2019
Cash Paid For Amounts Included In Measurement of Liabilities	$	39.4	$	32.3
Operating Cash Flows From Financing Leases	3.6		3.9
Operating Cash Flows From Operating Leases	30.7		23.5
Financing Cash Flows From Financing Leases	5.1		4.9
ROU Assets Obtained In Exchange For New Financing Liabilities (1)	—		—
ROU Assets Obtained In Exchange For New Operating Liabilities (2)	31.6		27.5

(1) We capitalized $83.1 of ROU financing assets upon adoption of the new lease standard in the first quarter of 2019 that are excluded from the figures for the year ended December 31, 2019. This figure excludes $44.2 of opening adjustments to ROU finance assets related, primarily, to prepayments of rent.
(2) We capitalized $172.2 of ROU operating assets upon adoption of the new lease standard in the first quarter of 2019 that are excluded from the figures for the year ended December 31, 2019. This figure excludes $26.6 of opening adjustments to ROU operating assets related, primarily, to prepayments of rent.

The following tables summarize maturities of lease liabilities and the reconciliation of lease liabilities as of December 31, 2020:


Lease Liability Maturity Summary
Year	Financing		Operating		Total
2021	$	9.0	$	34.4	$	43.4
2022	9.2		32.0		41.2
2023	9.2		25.2		34.4
2024	9.4		22.5		31.9
2025	9.6		20.7		30.3
Thereafter	45.0		103.1		148.1


Reconciliation of Lease Liabilities:	Financing			Operating			Total
Weighted-average Remaining Lease Term (years)	9.67			8.87			9.08
Weighted-average Discount Rate	4.9		%	3.4		%	3.8		%

Total Undiscounted Lease Liability	$	91.4		$	237.9		$	329.3
Imputed Interest	18.5			32.7			51.2
Total Discounted Lease Liability	72.9			205.2			278.1

The following table summarizes the reconciliation of lease liabilities as of December 31, 2019:


Reconciliation of Lease Liabilities:	Financing			Operating			Total
Weighted-average Remaining Lease Term (years)	10.67			10.17			10.32
Weighted-average Discount Rate	4.9		%	4.1		%	4.3		%

Total Undiscounted Lease Liability	$	100.2		$	223.6		$	323.8
Imputed Interest	22.1			40.7			62.8
Total Discounted Lease Liability	78.1			182.9			261.0

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Asset Acquisition and In-License Agreements We have entered into asset purchase agreements, license agreements, and option arrangements in order to advance and obtain technologies and services related to our business. These agreements generally require us to pay an initial fee and certain agreements call for future payments upon the attainment of agreed upon development, regulatory and/or commercial milestones. These agreements may also require minimum royalty payments based on sales of products developed from the applicable technologies, if any. In January 2019, we entered into an agreement with Caelum, a biotechnology company that is developing CAEL-101 for light chain (AL) amyloidosis. Under the terms of the agreement, we acquired a minority equity interest in preferred stock of Caelum and an exclusive option to acquire the remaining equity in Caelum based on Phase II data, for pre-negotiated economics. We paid $30.0 in the first quarter 2019 and agreed to pay up to an additional $30.0 in contingent development milestones prior to exercising the option to acquire the remaining equity in Caelum. These contingent payments meet the definition of a derivative liability and were initially recorded at fair value of $27.1. We allocated the total consideration of $57.1, inclusive of the fair value of the contingent payments, to the equity investment in Caelum and the option to acquire the remaining equity in Caelum based on the relative fair values of the assets. Following discussions with the FDA, Caelum changed its clinical development plan for CAEL-101 in the fourth quarter 2019. In December 2019, we amended the terms of the agreement with Caelum to modify the option to acquire the remaining equity in Caelum based on data from the modified Phase II/III trials. The amendment also modified the development-related milestone events associated with the initial $30.0 in contingent payments, provided for an additional $20.0 in upfront funding, which we accrued as of December 31, 2019 as well as funding of $60.0 in exchange for an additional equity interest at fair value upon achievement of a specific development-related milestone event. We paid the additional $20.0 in upfront funding and the initial $30.0 in contingent payments in 2020. The agreement with Caelum also provides for additional payments, in the event Alexion exercises the purchase option, for up to $500.0, which includes an upfront option exercise payment and potential regulatory and commercial milestone payments. A Phase II trial for CAEL-101 commenced during the first quarter of 2020 and met its primary objectives, supporting the safety and tolerability of CAEL-101 and confirmed the dose and regimen to be adopted for the Phase III studies. In September 2020, Alexion and Caelum announced the initiation of the Cardiac Amyloid Reaching for Extended Survival (CARES) program. This includes two parallel Phase III trials to evaluate the survival benefits of CAEL-101. In December 2020, in connection with entering into the Merger Agreement with AstraZeneca, we determined that the fair value of our option to acquire the remaining equity of Caelum decreased as a result of a change to the expected option exercise date. This resulted in a $49.0 impairment charge which we recorded to investment income, net (refer to Note 7, Other Investments). In March 2019, we entered into an agreement with Zealand which provides us with exclusive worldwide licenses, as well as development and commercial rights, for subcutaneously delivered preclinical peptide therapies directed at up to four complement pathway targets. Pursuant to the agreement, Zealand will lead joint discovery and research efforts through the preclinical stage, and Alexion will lead development efforts beginning with the investigational new drug filing and Phase I studies. In addition to the agreement, we made an equity investment in Zealand (refer to Note 7, Other Investments). Under the terms of the agreement, we made an upfront payment of $40.0 for an exclusive license to the lead target and the equity investment, as well as for preclinical research services to be performed by Zealand in relation to the lead target. The market value of the equity investment was $13.8 as of the date of acquisition, which we recorded in other assets in our consolidated balance sheets. We also recognized prepaid research and development expense of $5.0 within the consolidated balance sheets associated with the research activities to be performed by Zealand. Due to the early stage of the asset we are licensing, we recorded the upfront license payment of $21.2 as research and development expense during the first quarter 2019. As of December 31, 2020, we could be required to pay up to $610.0, for the lead target, upon the achievement of specified development, regulatory and commercial milestones, as well as royalties on commercial sales. In addition, we could be required to pay up to an additional $115.0 in development and regulatory milestones if both a long-acting and short-acting product are developed with respect to the lead target. Each of the three subsequent targets can be selected for an option fee of $15.0 and has the potential for additional development, regulatory and commercial milestones, as well as royalty payments, at a reduced price to the lead target. In April 2019, we entered into an agreement with Affibody AB (Affibody), through which Alexion obtained an exclusive worldwide license, as well as development and commercial rights, to ABY-039, a bivalent antibody-mimetic that targets the neonatal Fc receptor (FcRn). Under the terms of the agreement, we made an upfront payment of $25.0 for the exclusive license to ABY-039. Due to the early stage of the asset we licensed, we recorded the upfront license payment as research and development expense during the second quarter 2019. In February 2020, based on data from our Phase I study, we terminated the agreement to co-develop ABY-039 with Affibody. In September 2019, we entered into an agreement with Eidos through which Alexion obtained an exclusive license to develop and commercialize AG10 in Japan. AG10 is a small molecule designed to treat the root cause of transthyretin amyloidosis (ATTR) and is currently in a Phase III study in the U.S., Europe, and Japan for ATTR cardiomyopathy (ATTR-CM). In addition, we made an equity investment in Eidos (refer to Note 7, Other Investments). Under the terms of the agreement, we made an upfront payment of $50.0 for the exclusive license to AG10 in Japan and the equity investment. The market value of the equity investment was $19.9 as of the date of acquisition, which we recorded in other assets in our consolidated balance sheets. Due to the early stage of the asset we are licensing, we recorded the upfront license payment of $30.1 as research and development expense during the third quarter 2019. As of December 31, 2020, we could also be required to pay $30.0 upon achievement of a Japanese-based regulatory milestone as well as royalties on commercial sales. In October 2019, we entered into an option agreement with Stealth BioTherapeutics Corp. (Stealth), a clinical-stage biotechnology company whose lead product candidate, elamipretide, was being investigated in late-stage clinical studies in three primary mitochondrial diseases - primary mitochondrial myopathy (PMM), Barth syndrome and Leber’s hereditary optic neuropathy. Under the terms of the agreement, we made an upfront payment of $30.0 for an equity investment in Stealth and an exclusive option to partner with Stealth in the development of subcutaneous elamipretide based on final results from the Phase III study in PMM. The market value of the equity investment was $9.6 as of the date of acquisition, which we recorded in other assets in our consolidated balance sheets. Due to the early stage of the asset for which we have an option to license, we recorded the upfront option payment of $20.4 as research and development expense during the fourth quarter 2019. In December 2019, Stealth announced that based on top-line data from the Phase 3 study in PMM, the study did not meet its primary endpoints. Following review of the Phase 3 data released in December 2019, we notified Stealth that we will not exercise the co-development option agreement. In October 2018, we entered into a collaboration agreement with Dicerna that provides us with exclusive worldwide licenses and development and commercial rights for two preclinical RNA interference (RNAi) subcutaneously delivered molecules for complement-mediated diseases, as well as an exclusive option for other preclinical RNAi molecules for two additional targets within the complement pathway. In addition to the collaboration agreement, we made an equity investment in Dicerna. Under the terms of the agreements, we made an upfront payment of $37.0 for the exclusive licenses and the equity investment. The market value of the equity investment was $10.3 as of the date of acquisition, which we recorded in other assets in our consolidated balance sheets. Due to the early stage of the assets we are licensing, we recorded the upfront license payment of $26.7 as research and development expense during the fourth quarter 2018. In December 2019, we exercised our option for exclusive rights to two additional targets within the complement pathway under an existing agreement with Dicerna, which expands our existing research collaboration and license agreement with Dicerna to include a total of four targets within the complement pathway. In connection with the option exercise, we paid Dicerna $20.0, which we recorded as research and development expense in the fourth quarter 2019. As of December 31, 2020, excluding accrued milestones, we could be required to pay up to $604.1 for amounts due upon the achievement of specified research, development, regulatory and commercial milestones on the four licensed targets, as well as royalties on commercial sales. In December 2017, we entered into a collaboration and license agreement with Halozyme Therapeutics, Inc. that allows us to use drug-delivery technology in the development of subcutaneous formulations for our portfolio of products for up to four targets. Under the terms of the agreement, we made an upfront payment of $40.0 for an exclusive license to two of the four potential targets and due to the early stage of the assets we are licensing, we recorded an expense for the upfront payment during the fourth quarter 2017. During the second quarter 2020, we forfeited our rights to one of the two targets we initially licensed. As of December 31, 2020, we could be required to pay up to $155.0 for the remaining licensed target upon achievement of specified development, regulatory and sales-based milestones, as well as royalties on commercial sales. Each of the two subsequent targets can be licensed for an option fee of $8.0, with contingent payments of up to $160.0 per target, subject to development, regulatory and commercial milestones, as well as royalties on commercial sales. In connection with our prior acquisition of Syntimmune, Inc., a clinical-stage biotechnology company developing an antibody therapy targeting the FcRn, we could be required to pay up to $800.0 upon the achievement of specified development, regulatory and commercial milestones, of which $130.0 is specific to the subcutaneous formulation. We are currently subject to a claim in litigation in connection with the Syntimmune acquisition alleging that Alexion failed to meet its obligations under the merger agreement to use commercially reasonable efforts to achieve the milestones and plaintiff has requested payment of the full earn-out amount. In addition, excluding accrued milestones, as of December 31, 2020, we have other license agreements under which we may be required to pay up to an additional $114.0 for currently licensed targets, if certain development, regulatory and commercial milestones are met, including up to $71.5 for the development of cerdulatinib in multiple indications pursuant to an in-licensing agreement with Astellas Pharma, Inc. which was assumed through the acquisition of Portola in the third quarter 2020. Additional amounts may be payable if we elect to acquire licenses to additional targets, as applicable, under the terms of these agreements. During the next 12 months, we may make milestone payments related to our asset acquisitions, option and in-license agreements of approximately $71.1, excluding milestones accrued as of December 31, 2020. Asset Sale and Out-License Arrangements In connection with prior asset sale and out-license arrangements, including those assumed by Alexion through the acquisition of Portola in the third quarter 2020, Alexion is entitled to receive contingent payments upon the achievement of various regulatory and commercial milestones and other events, as well as royalties on commercial sales. The amount of contingent consideration related to these agreements is fully constrained and therefore has not been recognized as of December 31, 2020. Manufacturing Agreements We have various manufacturing development and license agreements to support our clinical and commercial product needs. We rely on Lonza, a third party manufacturer, to produce a portion of commercial and clinical quantities of our commercial products and product candidates. We have various manufacturing and license agreements with Lonza, with remaining total non-cancellable future commitments of approximately $1,137.8 through 2030. This amount includes $100.5 of undiscounted, fixed payments applicable to our Contract Manufacturing Organization (CMO) embedded lease arrangement with Lonza. If we terminate certain supply agreements with Lonza without cause, we will be required to pay for product scheduled for manufacture under our arrangement. Under an existing arrangement with Lonza, we pay Lonza a royalty on the sales of SOLIRIS and ULTOMIRIS manufactured at Lonza facilities. In addition to our commitments with Lonza, as of December 31, 2020 we have non-cancellable commitments of approximately $175.6 through 2023 with other third party manufacturers. Contingent Liabilities We are currently involved in various claims, disputes, lawsuits, investigations, administrative proceedings and legal proceedings. On a quarterly basis, we review the status of each significant matter and assess its potential financial exposure. In accordance with generally accepted accounting principles, if the potential loss from any claim, asserted or unasserted, or legal proceeding is considered probable and the amount can be reasonably estimated, we accrue a liability for the estimated loss. Because of uncertainties related to claims, proceedings and litigation, accruals are based on our best estimates based on information available at the time of the assessment. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation, court decisions or settlement of claims (and offers of settlement), we may reassess the potential liability related to these matters and may revise these estimates, which could result in a material adverse adjustment to our operating results. Costs associated with our involvement in legal proceedings are expensed as incurred. The outcome of any such proceedings, regardless of the merits, is inherently uncertain. If we were unable to prevail in any such proceedings, our consolidated financial position, results of operations, and future cash flows may be materially impacted. We have received, and may in the future receive, notices from third parties claiming that their patents may be infringed by the use, development, manufacture, importation or sale of our products or product candidates. Under the guidance of ASC 450, Contingencies, we record a royalty accrual based on our best estimate of the fair value percent of net sales of our products that we could be required to pay the owners of patents for technology used in the manufacture and sale of our products. A costly license, or inability to obtain a necessary license, could have a material adverse effect on our financial results. In May 2015, we received a subpoena in connection with an investigation by the Enforcement Division of the Securities and Exchange Commission (SEC) requesting information related to our grant-making activities and compliance with the Foreign Corrupt Practices Act (FCPA) in various countries. In addition, in October 2015, we received a request from the Department of Justice (DOJ) for the voluntary production of documents and other information pertaining to Alexion’s compliance with the FCPA. The SEC and DOJ also sought information related to Alexion’s recalls of specific lots of SOLIRIS and related securities disclosures. The investigations focused on operations in various countries, including Brazil, Colombia, Japan, Russia and Turkey, and Alexion's compliance with the FCPA and other applicable laws. In May 2020, DOJ informed us that it has closed its inquiry into these matters. On July 2, 2020, we reached a civil settlement with the SEC fully resolving the SEC’s investigation into possible violations of the FCPA. Alexion neither admitted nor denied any wrongdoing in connection with the settlement but agreed to pay $21.5 to the SEC, consisting of amounts attributable to disgorgement, civil penalties, and pre-judgment interest. In connection with this settlement, in July 2020, we paid $21.5 to the SEC. Following the settlement with the SEC, the Ministry of Health in Turkey initiated an investigation regarding the matters referenced in the SEC Order as they relate to the Company’s operations in Turkey between 2010 and 2015. We are cooperating with this investigation. Alexion is committed to continually focusing on its compliance program and continues to enhance its comprehensive company-wide program that is designed to enhance our business processes, structures, controls, training, talent, and systems across Alexion’s global operations. As previously reported, on December 29, 2016, a shareholder filed a putative class action against the Company and certain former employees in the U.S. District Court for the District of Connecticut, alleging that defendants made misrepresentations and omissions about SOLIRIS. On April 12, 2017, the court appointed a lead plaintiff. On July 14, 2017, the lead plaintiff filed an amended putative class action complaint against the Company and seven current or former employees. Defendants moved to dismiss the amended complaint on September 12, 2017. Plaintiffs filed an opposition to defendants’ motion to dismiss on November 13, 2017, and defendants filed a reply brief in further support of their motion on December 28, 2017. On March 26, 2019, the court held a telephonic status conference. During that conference, the court informed counsel that it was preparing a ruling granting the defendants’ pending motion to dismiss. The court inquired of plaintiffs’ counsel whether they intended to seek leave to amend their complaint, and indicated that if they wished to file a second amended complaint, they would be allowed to do so. On April 2, 2019, the court granted plaintiffs until May 31, 2019 to file a second amended complaint, thereby rendering moot defendants’ pending motion to dismiss. On June 2, 2019, plaintiffs filed a second amended complaint against the same defendants. The complaint alleges that defendants engaged in securities fraud, including by making misrepresentations and omissions in its public disclosures concerning the Company’s SOLIRIS sales practices, management changes, and related investigations, between January 30, 2014 and May 26, 2017, and that the Company's stock price dropped upon the purported disclosure of the alleged fraud. The plaintiffs seek to recover unspecified monetary relief, unspecified equitable and injunctive relief, interest, and attorneys’ fees and costs. Defendants’ filed a motion to dismiss the amended complaint on August 2, 2019; plaintiffs’ filed their opposition to that motion on October 2, 2019; and defendants’ filed their reply in further support of their motion on November 15, 2019. Given the early stage of these proceedings, we cannot presently predict the likelihood of obtaining dismissal of the case (or the ultimate outcome of the case if the motion to dismiss is denied by the court), nor can we estimate the possible loss or range of loss at this time. In December 2016, we received a subpoena from the U.S. Attorney's Office for the District of Massachusetts requesting documents relating generally to our support of Patient Services, Inc. (PSI) and National Organization for Rare Disorders (NORD), 501(c)(3) organizations that provide financial assistance to Medicare patients taking drugs sold by Alexion; Alexion’s provision of free drug to Medicare patients; and Alexion compliance policies and training materials concerning the anti-kickback statute and information on donations to PSI and NORD from 2010 through 2016. In April 2019, we entered into a civil settlement agreement with the DOJ and the Office of Inspector General (OIG) of the U.S. Department of Health and Human Services to resolve this matter. As part of the settlement agreement, Alexion paid $13.1 to the DOJ and OIG. OIG did not require a Corporate Integrity Agreement with Alexion because it made fundamental organizational changes, including hiring a new executive leadership team, replacing half of the members of its Board of Directors, and effecting a significant change in the workforce. In May 2017, Brazilian authorities seized records and data from our São Paulo, Brazil offices as part of an investigation being conducted into Alexion’s Brazilian operations. We are cooperating with this inquiry. In June 2017, we received a demand to inspect certain of our books and records pursuant to Section 220 of the General Corporation Law of the State of Delaware on behalf of a purported stockholder. Among other things, the demand sought to determine whether to institute a derivative lawsuit against certain of the Company’s directors and officers in relation to the investigation by our Audit and Finance Committee announced in November 2016 and the investigations instituted by the SEC, DOJ, U.S. Attorney’s Office for the District of Massachusetts, and Brazilian law enforcement officials that are described above. We have responded to the demand. Given the early stages of this matter, an estimate of the possible loss or range of loss cannot be made at this time. On September 27, 2017, a hearing panel of the Canadian Patented Medicine Prices Review Board (PMPRB) issued a decision in a previously pending administrative pricing matter that we had excessively priced SOLIRIS in a manner inconsistent with the Canadian pricing rules and guidelines. In its decision, the PMPRB ordered Alexion to decrease the price of SOLIRIS to an upper limit based upon pricing in certain other countries, and to forfeit excess revenues for the period between 2009 and 2017. The amount of excess revenues for the period between 2009 and 2017 was determined not to be a material amount and was paid in 2018. In October 2017, Alexion filed an application for judicial review of the PMPRB’s decision in the Federal Court of Canada. On May 23, 2019, the Federal Court of Canada dismissed Alexion's application for judicial review and, as a consequence, affirmed the decision of the PMPRB that we had excessively priced SOLIRIS. On June 21, 2019, Alexion filed a notice of appeal of the Federal Court of Canada's ruling, and, on October 17, 2019, Alexion filed a memorandum of fact and law in support of the appeal. On December 3, 2019, the Attorney General of Canada filed its memorandum of fact and law in support of the Federal Court of Canada's dismissal of Alexion's appeal of the PMPRB's decision. On December 19, 2019, the intervenor, the Minister of Health for the Province of British Columbia, filed a separate memorandum of fact and law in support of the Federal Court of Canada's decision. The Canadian Federal Court of Appeal heard the appeal on October 21 and 22, 2020, but has not issued a decision as of the date of this filing. Pursuant to an order made by the Federal Court of Canada, as of February 4, 2021, we have placed approximately $70.7 in escrow to secure our obligations pending the final resolution of all appeals in this matter. This amount reflects the difference between the list price for SOLIRIS and the price determined by the PMPRB to be non-excessive for sales of SOLIRIS in Canada for the period beginning September 2017 through December 31, 2020. In addition, on a quarterly basis, until the appeals process has concluded, Alexion will be required to place amounts into escrow for each vial of SOLIRIS sold in the applicable quarter equal to the difference between the list price for SOLIRIS and the price determined by the PMPRB to be non-excessive. Our revenues in Canada have been reduced by $49.2 cumulatively to date, which is our current best estimate of our liability through December 31, 2020 if we lose the appeal of this matter (the amount of our ultimate liability, however, may be greater than this estimate when the appeal process for this matter is concluded). Chugai Pharmaceutical Co., Ltd. has filed three lawsuits against Alexion. The first was filed in November 2018 in the United States District Court for the District of Delaware against Alexion Pharmaceuticals, Inc. alleging that ULTOMIRIS infringes one U.S. patent held by Chugai Pharmaceutical Co., Ltd. Upon issuance of a new U.S. patent on November 12, 2019, Chugai filed a second lawsuit in the United States alleging that ULTOMIRIS infringes the new patent. The parties have agreed to consolidate the November 2018 and November 2019 lawsuits. Chugai filed a third lawsuit in December 2018 in the Tokyo District Court against Alexion Pharma GK (a wholly-owned subsidiary of Alexion) in Japan, and alleges that ULTOMIRIS infringes two Japanese patents held by Chugai Pharmaceutical Co., Ltd. Chugai’s complaints seek unspecified damages and certain injunctive relief. On March 5, 2020, the Supreme Court of Japan dismissed Chugai's appeal against an earlier IP High Court of Japan decision which held that one of the Chugai patents-in-suit is invalid. Subsequently Chugai filed a correction to the claims of this patents-in-suit and Alexion has countered that the corrected claims are still invalid and not infringed. In all cases, Alexion has denied the charges and countered that the patents are neither valid nor infringed. A trial date for the U.S. case which was initially set for July 2021 has been re-scheduled for January 2022. The case is still at the briefing stage in Japan. Given the early stages of these litigations, an estimate of the possible loss or range of loss cannot be made at this time. On February 28, 2019, Amgen Inc. (Amgen) petitioned the U.S. Patent and Trademark Office (PTO) to institute Inter Partes Review (IPR) of three patents owned by Alexion that relate to SOLIRIS: U.S. Patent Nos. 9,725,504; 9,718,880; and 9,732,149. In each case, Amgen alleged the patented subject matter was anticipated and/or obvious in view of prior art, and that the patent claims are therefore invalid. On August 30, 2019, the PTO instituted IPRs of each of the three patents. On May 28, 2020, we entered into a Confidential Settlement and License Agreement (the “Settlement Agreement”) with Amgen to settle the three IPRs at the Patent Trial and Appeal Board (“PTAB”) of the PTO. Pursuant to the Settlement Agreement, Alexion and Amgen have terminated each of the pending IPRs. In addition, effective March 1, 2025 (or an earlier date in certain circumstances), the Company grants to Amgen (and its affiliates and certain partners) a non-exclusive, royalty-free, license under U.S. patents and patent applications related to eculizumab and various aspects of the eculizumab product that Alexion currently markets and sells under the tradename SOLIRIS. This license will allow Amgen (and its affiliates and certain partners), effective March 1, 2025, the right to make, have made, use, import, have imported, sell, have sold, offer for sale, have offered for sale, distribute, and have distributed in, or for, the U.S., an eculizumab product. In connection with an ongoing matter, in August 2019, the Brazilian Federal Revenue Service provided a Notice of Tax and Description of the Facts (the “Tax Assessment”) to two Alexion subsidiaries (the "Brazil Subsidiaries"), as well as to two additional entities, a logistics provider utilized by Alexion and a distributor. The Tax Assessment focuses on the importation of SOLIRIS vials pursuant to Alexion’s free drug supply to patients program (referred to as Global Access to Medicines, or GATM) in Brazil. In September 2019, the Brazil Subsidiaries filed defenses to the Tax Assessment disputing the basis for liability under the Tax Assessment, based on, among others, the following: in connection with the operation of GATM, during the period from September 2014 to June 2019: (i) the importers responsible for the importation of the GATM SOLIRIS vials into Brazil were correctly identified and (ii) the correct customs value was utilized for the purpose of importing the GATM SOLIRIS vials provided to the patients free of charge. The defenses filed by Alexion are pending judgment at the first level of administrative appeals within the Brazilian federal administrative proceeding system. There are three separate levels of administrative appeals within the Brazilian federal administrative proceeding system and, if the outcome of these administrative appeals is unfavorable, the final decision of the federal administrative proceeding system can be disputed to the federal court systems in Brazil (at this time, Alexion intends to appeal the Tax Assessment if it is not overturned in the course of administrative appeals). Given the early stage of these proceedings, Alexion is unable to predict the duration, scope or outcome of this matter, but we expect that a final resolution will take three years or more. While it is possible that a loss related to the Tax Assessment may be incurred, given its ongoing nature, we cannot reasonably estimate the potential magnitude of any such possible loss or range of loss, or the cost of the ongoing administrative appeals (and potential appeals to the federal court system) of the Tax Assessment. Any determination that any aspects of the importation of free of charge medications into Brazil as set forth in the Tax Assessment are not, or were not, in compliance with existing laws or regulations could result in the imposition of fines, civil penalties and, potentially criminal penalties, and/or other sanctions against us, and could have an adverse impact on our Brazilian operations. In connection with Alexion’s acquisition of Portola, we have assumed litigation to which Portola was a party. Among the litigation assumed is a securities fraud class action filed against Portola and certain of its officers, directors and underwriters (“Defendants”) under the Securities Act of 1933 and the Securities Exchange Act of 1934. Specifically, on January 16, 2020, February 7, 2020, and February 28, 2020, stockholders filed three putative class actions in the U.S. District Court for the Northern District of California, captioned Hayden v. Portola Pharmaceuticals, Inc., et al., No. 3:20-cv-00367-VC (N.D. Cal.); McCutcheon v. Portola Pharmaceuticals, Inc., et al., No. 3:20-cv-00949 (N.D. Cal.); and Southeastern Pennsylvania Transportation Authority v. Portola Pharmaceuticals, Inc., et al., No. 3:20-cv-01501 (N.D. Cal.). These cases have since been consolidated, and on April 22, 2020, the Court issued an Order appointing the Alameda County Employees’ Retirement Association (“ACERA”) as Lead Plaintiff in the litigation. ACERA filed its amended consolidated complaint on May 20, 2020, asserting that Defendants made misrepresentations and omissions in public disclosures (including in materials issued in connection with the August 7, 2019 securities offering) concerning Portola’s sales of andexanet alfa, marketed as ANDEXXA in the United States and ONDEXXYA in Europe, between January 8, 2019 and February 26, 2020. Specifically, plaintiffs allege that Defendants made materially false and/or misleading statements about the demand for ANDEXXA, usage of ANDEXXA by hospitals and healthcare organizations, and about Portola’s accounting for its return reserves. Plaintiffs contend that the alleged fraud was revealed on January 9, 2020, when Portola announced its preliminary unaudited financial results for the fourth quarter of 2019, and again on February 26, 2020, when Portola issued its fourth quarter 2019 financial results. In July 2020, Portola and the Portola Defendants filed a motion to dismiss with the Court. The court heard oral argument on September 24, 2020 and granted defendants’ pending motion to dismiss, but with leave for plaintiffs to amend further their complaint. Plaintiffs filed an amended complaint on November 5, 2020. In December 2020, Portola and Portola Defendants filed a motion to dismiss with the Court. Oral argument is scheduled for February 25, 2021. Plaintiffs seek to recover unspecified monetary relief, interest, and attorneys’ fees and costs. Given the early stage of these proceedings, we cannot presently predict the likelihood of obtaining dismissal of the case (or the ultimate outcome of the case if that motion to dismiss is denied by the court), nor can we estimate the possible loss or range of loss at this time.

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

Income tax expense is based on income before income taxes as follows:


	Year Ended December 31,
	2020		2019		2018
U.S.	$	(1,098.5)	$	2.0	$	(451.4)
Non-U.S.	1,667.5		2,176.8		693.6
	$	569.0	$	2,178.8	$	242.2

During the fourth quarter of 2013, in connection with the centralization of our global supply chain and technical operations in Ireland, our U.S. parent company became a direct partner in a captive foreign partnership. The partnership income, which is derived in foreign jurisdictions, is classified as “non-U.S. income” for purposes of financial reporting. Substantially all non-U.S. income relates to income from our captive foreign partnership.

The components of income tax expense are as follows:


	Year Ended December 31,
	2020		2019		2018
Domestic
Current	$	3.1	$	71.8	$	57.0
Deferred	(382.1)		1,731.0		49.5
	(379.0)		1,802.8		106.5
Foreign
Current	245.9		158.2		74.7
Deferred	98.7		(2,186.5)		(16.6)
	344.6		(2,028.3)		58.1
Total
Current	249.0		230.0		131.7
Deferred	(283.4)		(455.5)		32.9
	$	(34.4)	$	(225.5)	$	164.6

We continue to pay cash taxes in U.S. federal, various U.S. state, and foreign jurisdictions where we have utilized all of our tax attributes or have met the applicable limitation for attribute utilization.

Effective Tax Rate

The provision (benefit) for income taxes differs from the U.S. federal statutory tax rate. The reconciliation of the statutory U.S. federal income tax rate to our effective income tax rate is as follows:


	Year Ended December 31,
	2020		2019		2018
U.S. federal statutory tax rate	21.0	%	21.0	%	21.0	%
Benefit of foreign earnings	(15.5)	%	(12.6)	%	(71.2)	%
Tax credits	(7.3)	%	(0.7)	%	(17.0)	%
Tax reserves	(0.6)	%	(0.1)	%	12.1	%
Acquired in-process research & development	—	%	—	%	102.6	%
Intra-entity asset transfer of intellectual property	0.4	%	(17.5)	%	—	%
Foreign-derived intangible income	(10.0)	%	(1.6)	%	(4.5)	%
U.S. state taxes	(1.6)	%	0.7	%	14.2	%
IRC 162(m) executive compensation	4.1	%	0.2	%	2.2	%
Other permanent differences	3.5	%	0.3	%	8.6	%

Effective Income Tax Rate	(6.0)	%	(10.3)	%	68.0	%

In our reconciliation of our statutory U.S. federal income tax rate to our effective tax rate above, we have included a benefit of foreign earnings amount which encapsulates the various tax impacts that result from our non-U.S. income. As a result of the Tax Cuts and Jobs Act of 2017 (Tax Act), a substantial portion of our foreign earnings are subject to the GILTI minimum tax at an effective rate which is lower than the U.S. statutory tax rate of 21.0%. While we are also subject to tax in foreign jurisdictions locally, the majority of these taxes are creditable against U.S. taxes imposed on foreign earnings. As a result, the effective tax rate on our foreign earnings is lower than the U.S. statutory rate.

In the year ended December 31, 2020, the benefit of foreign earnings includes foreign local tax expense of $270.8, which is offset by the benefit from U.S. foreign tax credits of $240.6, resulting in a net increase to the effective tax rate of 5.3%. We incurred U.S. tax expense on our foreign earnings of $201.5, which includes GILTI minimum tax. The U.S. tax on our foreign earnings reflects a benefit of $148.7, or 26.1%, primarily related to the Section 250(a) deduction, compared to the U.S. statutory rate. The benefit from foreign earnings also includes the impact of certain current year events as described below.

In the year ended December 31, 2020, other permanent differences includes an increase to the effective tax rate of 1.5%, or $8.5, associated with nondeductible contingent consideration in the form of non-tradeable contingent value rights (CVRs) relating to the Achillion acquisition. Also included in other permanent differences is a decrease to the effective tax rate of 1.1%, or $6.2, associated with a nontaxable gain from our Portola equity investment which was included in the fair value of consideration transferred in connection with the Portola acquisition.

During the second quarter 2020, we recognized an impairment charge of $2,042.3 related to the KANUMA intangible asset, resulting in a deferred tax benefit of $377.3. Refer to Note 4, Intangible Assets and Goodwill, for additional information on the impairment charge. These deferred tax benefits decreased the effective tax rate for the year ended December 31, 2020 by approximately 19.2%.

In August 2020, we received a notice of examination from the Dutch Tax Authorities (“DTA”) regarding certain matters relating to our 2014 through 2017 tax years. We entered into an agreement with the DTA in December 2020 and have agreed to pay approximately $73.8 in connection with the settlement, inclusive of the 2018 and 2019 tax years. After taking into account the $56.1 U.S. foreign tax credit claimed on the settlement, the net cash outflow was $17.7, representing a 3.1% net increase to the effective tax rate. This net tax expense is reflected within benefit from foreign earnings.

In April 2020 we became aware of a European withholding tax regulation that could be interpreted to apply to certain of our previous intra-group transactions. We continue to evaluate whether the interpretation of this regulation applies to our facts and circumstances, and, based on our preliminary analysis, we recorded an immaterial reserve related to this matter during the second quarter of 2020.

In the year ended December 31, 2019, the benefit of foreign earnings includes foreign local tax expense of $193.2, which is offset by the benefit from U.S. foreign tax credits of $196.1, resulting in a net decrease to the effective tax rate of 0.1%. We incurred U.S. tax expense on our foreign earnings of $187.6, which includes GILTI minimum tax. The U.S. tax on our foreign earnings reflects a benefit of $269.5, or 12.4%, primarily related to the Section 250(a) deduction, compared to the U.S. statutory rate. The benefit from foreign earnings also includes certain one-time tax benefits associated with the intellectual property of Wilson Therapeutics. The deferred tax benefits include $95.7 and $30.3 associated with a tax election made with respect to intellectual property of Wilson Therapeutics and a valuation allowance release and corresponding recognition of net operating losses, respectively. On July 1, 2019, the Wilson Therapeutics intellectual property was integrated into the Alexion corporate structure, resulting in income tax expense of approximately $10.2.

A comprehensive analysis of our prior year estimate related to our foreign-derived intangible income (“FDII”) was completed during the third quarter 2019 based on additional guidance provided in the proposed regulations issued by the U.S. Treasury Department in 2019. The analysis resulted in income tax benefit of $17.0 related to prior year, which was recorded as a change in estimate in income tax expense in our consolidated statements of operations, resulting in a decrease of approximately 0.8% to our effective tax rate.

In the year ended December 31, 2019, the Company completed an intra-entity asset transfer of certain intellectual property to an Irish subsidiary within our captive foreign partnership. The Company recognized deferred tax benefits of $2,221.5 which represents the difference between the basis of the intellectual property for financial statement purposes and the basis of the intellectual property for tax purposes, applying the appropriate enacted

statutory tax rates. The Company will receive future tax deductions associated with amortization of the intellectual property, and any amortization not deducted for tax purposes will be carried forward indefinitely under Irish tax law. An offsetting deferred tax expense of $1,839.3 has been recognized to reflect the reduction of future foreign tax credits associated with the foreign local tax amortization deductions. These net deferred tax benefits resulted in a decrease of approximately 17.5% to our effective tax rate.

In the year ended December 31, 2018, the benefit of foreign earnings includes foreign local tax expense of $58.1, substantially all of which is offset by the benefit from U.S. foreign tax credits of $54.2, resulting in a net increase to the effective tax rate of 1.6%. We incurred U.S. tax expense on our foreign earnings of $206.1, which includes GILTI minimum tax. The U.S. tax on our foreign earnings reflects a benefit of $108.7, or 44.8%, primarily related to the Section 250(a) deduction, compared to the U.S. statutory rate. Also included in this component is a benefit of $67.7 from adjustments to 2018 provisional accounting for the Tax Act, which resulted in a decrease to our effective tax rate of approximately 28.0%.

The effective tax rate reconciliation includes the tax impact of acquisitions of IPR&D assets. Absent successful clinical results and regulatory approval, there is no alternative use for certain acquired IPR&D assets. An increase to the effective tax rate results when the value of such assets are expensed, and no tax benefit is recognized. In the year ended December 31, 2018, this component of the effective tax rate includes an increase to tax expense of $248.4 related to the acquired IPR&D costs for the acquisitions of Wilson Therapeutics and Syntimmune, which increased our effective tax rate by 69.7% and 32.9%, respectively.

In the year ended December 31, 2018, other permanent differences include tax expense of $15.8 or 6.5% related to other nondeductible compensation.

The Tax Act

In December 2017, the Tax Act was enacted into law. The Tax Act decreased the US federal corporate tax rate to 21.0%, imposed a minimum tax on foreign earnings related to intangible assets (GILTI), a one-time transition tax on previously unremitted foreign earnings, and modified the taxation of other income and expense items. With regard to the GILTI minimum tax, foreign earnings are reduced by the profit attributable to tangible assets and a deductible allowance of up to 50.0%, subject to annual limitations. We have elected to account for the impact of the minimum tax in deferred taxes.

We calculated provisional amounts for the tax effects of the Tax Act that could be reasonably estimated, but not completed, in our results for the year ended December 31, 2017. As of the fourth quarter 2018 we had completed our analysis of all provisional estimates, and concluded as follows:

(a)We calculated a reasonable estimate of the one-time transition tax on previously unremitted earnings, which resulted in an increase to U.S. Federal tax expense of $177.9 and an increase to taxes payable, net of tax credits, of $28.0 in the period ended December 31, 2017. Our initial accounting for the transition tax was not complete as of December 31, 2017 because there was uncertainty regarding the calculation of the amounts subject to the tax. We completed our analysis of the transition tax and related interpretive guidance during the third quarter 2018. No significant measurement period adjustment to our initial accounting was required.

(b)We calculated a reasonable estimate of the impact of the GILTI minimum tax on deferred taxes, which resulted in an increase to U.S. Federal tax expense and the deferred tax liability of $236.9 in the period ended December 31, 2017. Our initial accounting for the minimum tax was incomplete because there was uncertainty regarding the calculation of the temporary differences subject to the minimum tax. We completed our analyses of these temporary differences and the expected timing and manner of their reversal during the fourth quarter 2018. We recorded measurement period adjustments during 2018 which resulted in a decrease to U.S. federal tax expense of $67.7.

(c)We calculated a reasonable estimate of the Tax Act’s limits on deductions for employee remuneration, including remuneration in kind, which resulted in an insignificant impact to tax expense, taxes payable, and deferred taxes in the period ended December 31, 2017. Our initial accounting for these limits was incomplete because there was uncertainty regarding the value of the deduction-limited remuneration. We completed our analysis of the relevant employee remuneration arrangements during the third quarter 2018. No measurement period adjustment to our initial accounting was required.

(d)We calculated a reasonable estimate of the impact of the Tax Act to U.S. state income taxes, which resulted in an increase to tax expense, taxes payable, and deferred taxes of $2.9, $2.2, and $0.7, respectively, in the period ended December 31, 2017. We interpreted the effect of the Tax Act's changes to federal law on each U.S. state's system of taxation as of the date of enactment. We completed additional analysis of the effect of modifications to federal deductions and income inclusions on U.S. state tax systems in the fourth quarter 2018. No measurement period adjustment to our initial accounting was required.

(e)We calculated the deferred tax liability related to our foreign captive partnership in the period ended December 31, 2017 consistent with our calculation in periods prior to enactment of the Tax Act. As a result, the deferred tax liability we recorded as of December 31, 2017 of $533.4 related to our foreign captive partnership was provisional. We completed additional analysis of the direct and indirect effects of the Tax Act during the fourth quarter 2018. We recorded measurement period adjustments during 2018 which resulted in an increase to U.S. state income tax expense and deferred taxes of $11.1.

Deferred Taxes

Provisions have been made for deferred taxes based on the differences between the basis of the assets and liabilities for financial statement purposes and the basis of the assets and liabilities for tax purposes using currently enacted tax rates and regulations that will be in effect when the differences are expected to be recovered or settled. The components of the deferred tax assets and liabilities are as follows:


	December 31,		December 31,
	2020		2019
Deferred tax assets:
Net operating losses	$	318.1	$	102.9
Income tax credits	465.1		328.1
Stock compensation	58.6		57.1
Accruals and allowances	138.8		65.2
Unrealized losses	25.4		18.8
Research and development expenses	1.9		3.5
Accrued royalties	1.2		0.8
ROU leases	45.8		46.2
Intangible assets	1,892.0		1,967.3
	2,946.9		2,589.9
Valuation allowance	(276.0)		(72.6)
Total deferred tax assets	2,670.9		2,517.3
Deferred tax liabilities:
Depreciable assets	(5.6)		(5.1)
Inventory fair value step-up	(53.5)		—
Investment in foreign partnership	(1,992.7)		(2,249.5)
ROU leases	(51.9)		(53.9)
Total deferred tax liabilities	(2,103.7)		(2,308.5)
Net deferred tax (liability) asset	$	567.2	$	208.8

As of December 31, 2020, we have tax effected federal and state net operating loss carryforwards of $210.4 and $108.1, respectively. Our net operating losses expire between 2022 and 2043, with the exception of $112.8 of federal and $1.9 state net operating losses that can be carried forward indefinitely. We also have federal and state income tax credit carryforwards of $417.0 and $83.5, respectively. The federal income tax credits expire between 2033 and 2040, whereas $51.6 of state income tax credit carryforwards expire between 2021 and 2035. The remaining $31.9 of state income tax credits can be carried forward indefinitely.

Included in the year ended December 31, 2020 are $75.7 of Connecticut state net operating loss carryforwards and $53.7 of Connecticut state income tax credit carryforwards. A change in the Connecticut state tax regime signed into law during 2019 phases out the capital-based component of the business tax. Once fully phased out in 2024, the Company will be subject to income-based taxes in the state of Connecticut. The Company anticipates generating tax credits in future years that exceed the amount that can otherwise be utilized. As a result, a full valuation allowance has been established against these carryforward attributes.

The increase in our net operating losses, income tax credits and valuation allowance primarily relates to the Achillion and Portola acquisitions. Refer to Note 2, Acquisitions, for additional information. We continue to maintain a valuation allowance against other certain deferred tax assets where realization is not certain. The following table represents a roll-forward of our valuation allowance on deferred tax assets:


	Valuation Allowance on Deferred Tax Assets
Balances, December 31, 2017	$	(3.4)
Additions charged to income tax expense	—
Additions charged to acquired in-process research and development	(17.1)
Reductions credited to income tax expense	0.9
Balances, December 31, 2018	$	(19.6)
Additions charged to income tax expense	(68.6)
Reductions credited to income tax expense	15.6
Balances, December 31, 2019	$	(72.6)
Additions charged to income tax expense	(18.8)
Additions charged to goodwill	(184.6)
Reductions credited to income tax expense	—
Balances, December 31, 2020	$	(276.0)

Included in our investment in foreign partnership above is a deferred tax liability of $1,194.3 associated with GILTI minimum tax.

Unrecognized Tax Benefits

We follow authoritative guidance regarding accounting for uncertainty in income taxes, which prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The interpretation also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosures, and transition.

The beginning and ending amounts of unrecognized tax benefits reconciles as follows:


	2020		2019		2018
Beginning of period balance	$	133.8	$	92.7	$	60.9
Increases for tax positions taken during a prior period	27.6		3.4		9.1
Decreases for tax positions taken during a prior period	(10.0)		(4.9)		(5.8)
Increases for tax positions taken during the current period	28.0		43.8		28.8
Decreases for tax positions related to settlements	(13.9)		—		—
Decreases for tax positions related to lapse of statute	(2.1)		(1.2)		(0.3)
	$	163.4	$	133.8	$	92.7

The total amount of accrued interest and penalties were not significant as of December 31, 2020. The total amount of tax benefit recorded during 2020, 2019, and 2018 which related to unrecognized tax benefits was $21.4,

$4.6 and $35.4, respectively. All of our unrecognized tax benefits, if recognized, would have a favorable impact on the effective tax rate.

It is reasonably possible that a portion of our unrecognized tax benefits could reverse within the next twelve months. Reversal of these amounts is contingent upon the completion of field audits by the taxing authorities in several jurisdictions, whether a tax adjustment is proposed, the nature and amount of any adjustment, and the administrative path to resolving the proposed adjustment. We cannot reasonably estimate the range of the potential change.

Tax Audits

We file federal and state income tax returns in the U.S. and in numerous foreign jurisdictions. The U.S. and foreign jurisdictions have statutes of limitations ranging from 3 to 6 years. However, the limitation period could be extended due to our tax attribute carryforward position in a number of our jurisdictions. The tax authorities generally have the ability to review income tax returns for periods where the limitation period has previously expired and can subsequently adjust tax attribute values.

In 2017, the Internal Revenue Service (IRS) commenced an examination of our U.S. income tax returns for 2015. During the second quarter of 2020 we received a Revenue Agent Report (RAR) and held discussions with the IRS regarding a proposed adjustment related to the valuation of certain intellectual property that was contributed into our captive partnership during 2015. The Company agreed with the adjustment outlined in the RAR and recognized a previously unrecognized tax benefit in the second quarter of 2020 that did not result in a significant impact to the financial statements. The IRS concluded its examination during the third quarter 2020 without additional adjustments.

As described above, we entered into an agreement with the DTA in December 2020 and have agreed to pay approximately $73.8 in connection with a settlement regarding certain matters relating to our 2014 through 2019 tax years.

Undistributed Earnings

We have recorded tax on the undistributed earnings of our controlled foreign corporation (CFC) subsidiaries. To the extent CFC earnings may not be repatriated to the U.S. as a dividend distribution due to limitations imposed by law, we have not recorded the related potential withholding, foreign local, and U.S. state income taxes.

Coronavirus Aid, Relief and Economic Security Act

In response to the market volatility and instability resulting from the COVID-19 pandemic, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was signed into law on March 27, 2020. The CARES Act lifts certain deduction limitations originally imposed by the Tax Act. Under the Tax Act, federal net operating losses (NOLs) generated after 2017 could not be carried back and utilization was limited to 80% of taxable income. The CARES Act allows for a five-year carryback of federal NOLs generated in 2018 through 2020 and eliminates the 80% taxable income limitation by allowing corporate entities to fully utilize NOL carryforwards to offset taxable income in 2018 through 2020. In addition, the CARES Act generally allows taxpayers to deduct interest up to 50% of adjusted taxable income (30% limit under the Tax Act) for tax years 2019 and 2020. The CARES Act also allows taxpayers with prior year alternative minimum tax (repealed by the Tax Act) (AMT) credits to accelerate refund claims to tax years beginning in 2018 and 2019 instead of recovering the credits over a period of years, as originally enacted by the Tax Act.

Additionally, the CARES Act raises the corporate charitable deduction limit to 25% of taxable income and provides a technical correction to the Tax Act to generally provide qualified improvement property a 15-year cost-recovery period and allow 100% bonus depreciation. The enactment of the CARES Act did not result in any material adjustments to our income tax provision for the year ended December 31, 2020, or to our U.S. federal and state net deferred tax liabilities as of December 31, 2020.

Share-based Compensation

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Share-based Compensation

2017 Incentive Plan

The 2017 Plan was approved by our stockholders in May 2017 and replaced the 2004 Plan effective May 10, 2017. The 2017 Plan is a broad based plan that provides for the grant of equity awards including restricted stock and restricted stock units (collectively referred to as Restricted Stock), incentive and non-qualified stock options, and other stock-related awards to our directors, officers, key employees and consultants, for up to a maximum of 18.2 shares in addition to awards outstanding under the 2004 Incentive Plan on or after March 14, 2017 that are subsequently canceled, cash settled, expired, forfeited, or otherwise terminated without the delivery of such shares, subject to the limitations in the 2017 Plan. Stock options granted under the 2017 Plan have a maximum contractual term of ten years from the date of grant, have an exercise price not less than the fair value of the stock on the grant date and generally vest over four years. Restricted Stock awards also generally vest over four years, with performance-based restricted stock units having a three-year vesting period.

Stock Options

A summary of the status of our stock options as of December 31, 2020, and changes during the year then ended is presented in the table and narrative below:


	Number of shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2019	3.0	$	119.51
Granted	—	75.10
Exercised	(0.7)	64.79
Forfeited and canceled	(0.1)	146.19
Outstanding as of December 31, 2020	2.2	$	134.15	3.52	$	67.3
Vested and unvested expected to vest as of December 31, 2020	2.2	$	134.15	3.52	$	67.2
Exercisable as of December 31, 2020	2.2	$	134.35	3.49	$	66.3

Total intrinsic value of stock options exercised during the years ended December 31, 2020, 2019 and 2018 was $39.3, $14.7 and $27.5, respectively. We primarily utilize newly issued shares to satisfy the exercise of stock options. The total fair value of options vested during the years ended December 31, 2020, 2019 and 2018 was $4.8, $10.1 and $27.2, respectively.

We did not grant any stock options during the years ended December 31, 2020, 2019 and 2018.

Restricted Stock

A summary of the status of our nonvested Restricted Stock as of December 31, 2020 and changes during the year then ended is as follows:


	Number of Shares	Weighted Average Grant Date Fair Value
Nonvested Restricted Stock as of December 31, 2019	4.3	$	128.24
Shares granted	3.9	100.95
Shares forfeited	(0.6)	119.07
Shares vested	(2.2)	122.86
Nonvested Restricted Stock as of December 31, 2020	5.4	$	111.54

The fair value of Restricted Stock at the date of grant is based on the fair market value of the shares of common stock underlying the awards on the date of grant. The weighted average fair value at the date of grant for Restricted Stock awards granted during the years ended December 31, 2020, 2019 and 2018, including restricted stock units with performance conditions, was $100.95, $133.89 and $119.27 per share, respectively. Included in

the number of shares granted during 2020 is 0.4 shares of replacement awards related to our acquisition of Portola and 0.3 shares relating to incremental shares earned for performance-based awards granted in prior years.

The total fair value of Restricted Stock vested during the years ended December 31, 2020, 2019 and 2018 was $271.3, $161.3 and $181.7, respectively. Restricted Stock vested during 2020 includes 0.6 shares with a total fair value of $71.8 due to accelerated vesting of Restricted Stock and performance-based awards.

During 2020, we granted 0.5 shares to senior management that include both market-based and non-market-based performance conditions which provide the recipient the right to receive restricted stock at the end of a three year performance period. We used payout simulation models to estimate the grant date fair value of these awards. The grant date fair value of these awards was estimated to be $94.03 based on the probable achievement of the performance targets. The expense recognized for performance-based awards during the years ended December 31, 2020, 2019 and 2018 was $66.6, $46.3 and $14.9, respectively.

Employee Stock Purchase Plan

During 2015, the Company adopted the ESPP under which employees can purchase shares of our common stock based on a percentage of their compensation subject to certain limits. The purchase price per share is equal to the lower of 85.0% of the fair market value of our common stock on the offering date or the purchase date with a six month look-back feature. Under the ESPP, up to 1.0 shares of common stock may be issued to eligible employees who elect to participate in the purchase plan. Shares issued and compensation expense recognized under the ESPP for the years ended December 31, 2020, 2019 and 2018 was not material.

Share-Based Compensation Expense

The following table summarizes the share-based compensation expense in the consolidated statements of operations:


	Year Ended December 31,
	2020		2019		2018
Cost of sales (exclusive of amortization of purchased intangible assets)	$	12.4	$	14.1	$	16.0
Research and development	68.6		61.8		57.5
Selling, general and administrative	179.7		161.1		129.5
Acquisition-related costs	20.4		—		—
Total share-based compensation expense	281.1		237.0		203.0
Income tax effect	(65.3)		(55.0)		(46.5)
Total share-based compensation expense, net of tax	$	215.8	$	182.0	$	156.5

Share-based compensation expense capitalized to inventory during the years ended December 31, 2020, 2019 and 2018 was $11.9, $12.9, and $14.5, respectively.

As of December 31, 2020, there was $366.3 of total unrecognized share-based compensation expense related to non-vested share-based compensation arrangements granted under our share-based compensation plans. The expense is expected to be recognized over a weighted-average period of 1.68 years.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2020
Common and Preferred Stock [Abstract]
Stockholders' Equity	Stockholders’ Equity Share Repurchases In November 2012, our Board of Directors authorized a share repurchase program. In February 2017, our Board of Directors increased the amount that we are authorized to expend on future repurchases to $1,000.0 under our repurchase program, which superseded all prior repurchase programs. The entire amount authorized pursuant to this February 2017 Board approval has been utilized. On October 22, 2019, the Board of Directors approved a share repurchase authorization of up to $1,000.0. On July 28, 2020, the Board of Directors approved a new share repurchase authorization of up to an additional $1,500.0. The repurchase program does not have an expiration date and we are not obligated to acquire a particular number of shares. The repurchase program may be discontinued at any time at our discretion. Under the program, we repurchased 4.9 and 3.8 shares of our common stock at a cost of $510.8 and $416.0 during the years ended December 31, 2020 and 2019, respectively. As of December 31, 2020, there is a total of $2,024.7 remaining for repurchases under the repurchase programs.

Other Comprehensive Income and Accumulated Other Comprehensive Income (Notes)

12 Months Ended

Dec. 31, 2020

Other Comprehensive Income and Accumulated Other Comprehensive Income [Abstract]

Other Comprehensive Income and Accumulated Other Comprehensive Income

The following table summarizes the changes in AOCI, by component, for the years ended December 31, 2020, 2019 and 2018:


	Defined Benefit Pension Plans		Unrealized Gains (Losses) from Debt Securities		Unrealized Gains (Losses) from Hedging Activities		Foreign Currency Translation Adjustment		Total Accumulated Other Comprehensive Income (Loss)
Balances, December 31, 2017	$	(4.8)	$	0.2	$	(13.9)	$	(15.9)	$	(34.4)
Other comprehensive income (loss) before reclassifications	1.5		0.1		32.9		(0.5)		34.0
Amounts reclassified from other comprehensive income	0.7		(0.6)		(9.4)		—		(9.3)
Net other comprehensive income (loss)	2.2		(0.5)		23.5		(0.5)		24.7
Balances, December 31, 2018	$	(2.6)	$	(0.3)	$	9.6	$	(16.4)	$	(9.7)
Other comprehensive income (loss) before reclassifications	(6.6)		0.2		(11.1)		(1.0)		(18.5)
Amounts reclassified from other comprehensive income	—		—		(38.6)		—		(38.6)
Net other comprehensive income (loss)	(6.6)		0.2		(49.7)		(1.0)		(57.1)
Balances, December 31, 2019	$	(9.2)	$	(0.1)	$	(40.1)	$	(17.4)	$	(66.8)
Other comprehensive income (loss) before reclassifications	(1.5)		0.1		(88.1)		5.7		(83.8)
Amounts reclassified from other comprehensive income	0.5		—		25.5		—		26.0
Net other comprehensive income (loss)	(1.0)		0.1		(62.6)		5.7		(57.8)
Balances, December 31, 2020	$	(10.2)	$	—	$	(102.7)	$	(11.7)	$	(124.6)

The table below provides details regarding significant reclassifications from AOCI during the years ended December 31, 2020, 2019 and 2018:


Details about Accumulated Other Comprehensive Income Components	Amount Reclassified From Accumulated Other Comprehensive Income during the year ended December 31,						Affected Line Item in the Consolidated Statements of Operations
	2020		2019		2018
Unrealized Gains (Losses) on Hedging Activity
Forward exchange forward contracts	$	4.7	$	36.8	$	(1.8)	Net product sales
Interest rate swap contracts	(37.5)		13.3		13.6		Interest expense
	(32.8)		50.1		11.8
	7.3		(11.5)		(2.4)		Income tax (benefit) expense
	$	(25.5)	$	38.6	$	9.4

Defined Benefit Pension Items
Amortization of prior service costs and actuarial losses	$	(0.7)	$	—	$	(0.3)
Curtailment	—		—		(0.6)
	(0.7)		—		(0.9)
	0.2		—		0.2		Income tax (benefit) expense
	$	(0.5)	$	—	$	(0.7)

Fair Value Measurement

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurement

Authoritative guidance establishes a valuation hierarchy for disclosure of the inputs to the valuation used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 inputs are unobservable inputs based on our own assumptions used to measure assets and liabilities at fair value.

The following tables present information about our assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2020 and 2019, and indicate the fair value hierarchy of the valuation techniques we utilized to determine such fair value.


		Fair Value Measurement at December 31, 2020
Balance Sheet Classification	Type of Instrument	Total		Level 1		Level 2		Level 3
Cash equivalents	Money market funds	$	833.7	$	—	$	833.7	$	—





Marketable securities	Mutual funds	$	34.9	$	34.9	$	—	$	—





Other assets	Equity securities	$	143.2	$	122.7	$	20.5	$	—
Prepaid expenses and other current assets	Foreign exchange forward contracts	$	26.1	$	—	$	26.1	$	—

Other current liabilities	Foreign exchange forward contracts	$	80.1	$	—	$	80.1	$	—
Other liabilities	Foreign exchange forward contracts	$	1.2	$	—	$	1.2	$	—


Other current liabilities	Interest rate contracts	$	45.9	$	—	$	45.9	$	—
Other liabilities	Interest rate contracts	$	45.4	$	—	$	45.4	$	—
Current portion of contingent consideration	Acquisition-related contingent consideration	$	114.9	$	—	$	—	$	114.9
Contingent consideration	Acquisition-related contingent consideration	$	299.4	$	—	$	—	$	299.4


		Fair Value Measurement at December 31, 2019
Balance Sheet Classification	Type of Instrument	Total		Level 1		Level 2		Level 3
Cash equivalents	Money market funds	$	635.9	$	—	$	635.9	$	—
Cash equivalents	Commercial paper	$	227.9	$	—	$	227.9	$	—
Cash equivalents	Corporate bonds	$	20.6	$	—	$	20.6	$	—
Cash equivalents	Bank certificates of deposit	$	19.2	$	—	$	19.2	$	—
Cash equivalents	Other government-related obligations	$	60.4	$	—	$	60.4	$	—
Marketable securities	Mutual funds	$	23.1	$	23.1	$	—	$	—
Marketable securities	Commercial paper	$	19.0	$	—	$	19.0	$	—
Marketable securities	Corporate bonds	$	3.7	$	—	$	3.7	$	—
Marketable securities	Other government-related obligations	$	10.0	$	—	$	10.0	$	—
Marketable securities	Bank certificates of deposit	$	8.2	$	—	$	8.2	$	—
Other assets	Equity securities	$	79.0	$	51.2	$	27.8	$	—
Prepaid expenses and other current assets	Foreign exchange forward contracts	$	29.9	$	—	$	29.9	$	—
Other assets	Foreign exchange forward contracts	$	0.6	$	—	$	0.6	$	—
Other current liabilities	Foreign exchange forward contracts	$	26.6	$	—	$	26.6	$	—
Other liabilities	Foreign exchange forward contracts	$	1.1	$	—	$	1.1	$	—
Other current liabilities	Interest rate contracts	$	19.5	$	—	$	19.5	$	—
Other liabilities	Interest rate contracts	$	41.9	$	—	$	41.9	$	—
Contingent consideration	Acquisition-related contingent consideration	$	192.4	$	—	$	—	$	192.4
Other current liabilities	Other contingent payments	$	24.0	$	—	$	—	$	24.0

There were no securities transferred between Level 1, 2 and 3 during the year ended December 31, 2020.

Valuation Techniques

We classify mutual fund investments and equity securities, which are valued based on quoted market prices in active markets with no valuation adjustment, as Level 1 assets within the fair value hierarchy.

Cash equivalents and marketable securities classified as Level 2 within the valuation hierarchy include money market funds, commercial paper, U.S. and foreign government-related debt, corporate debt securities and certificates

of deposit. We estimate the fair values of these marketable securities by taking into consideration valuations obtained from third-party pricing sources. These pricing sources utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include market pricing based on real-time trade data for similar securities, issuer credit spreads, benchmark yields, and other observable inputs. We validate the prices provided by our third-party pricing sources by understanding the models used, obtaining market values from other pricing sources and analyzing pricing data in certain instances.

Other investments in equity securities of publicly traded companies which are subject to holding period restrictions are carried at fair value using an option pricing valuation model and classified as Level 2 equity securities within the fair value hierarchy. The most significant assumptions within the option pricing valuation model are the term of the restrictions and the stock price volatility, which is based upon the historical volatility of the applicable company or similar companies. We also use a constant maturity risk-free interest rate to match the remaining term of the restrictions on such investments.

Our derivative assets and liabilities include foreign exchange and interest rate derivatives that are measured at fair value using observable market inputs such as forward rates, interest rates, our own credit risk as well as an evaluation of our counterparties’ credit risks. Based on these inputs, the derivative assets and liabilities are classified within Level 2 of the valuation hierarchy.

Contingent consideration liabilities related to business acquisitions and derivative liabilities associated with other contingent payments are classified as Level 3 within the valuation hierarchy and are valued based on various estimates, including probability of success, discount rates and amount of time until the conditions of the milestone payments are met.

As of December 31, 2020, there has not been any impact to the fair value of our derivative liabilities due to our own credit risk. Similarly, there has not been any significant adverse impact to our derivative assets based on our evaluation of our counterparties’ credit risks.

Acquisition-Related Contingent Consideration

In connection with prior business combinations, we may be required to pay future consideration that is contingent upon the achievement of specified development, regulatory approvals or sales-based milestone events. We determine the fair value of these obligations using various estimates that are not observable in the market and represent a Level 3 measurement within the fair value hierarchy. As of December 31, 2020, the resulting probability-weighted cash flows were discounted using a cost of debt ranging from 2.8% to 3.3% for developmental and regulatory milestones and a weighted average cost of capital of 9.0% for sales-based milestones.

Each reporting period, we adjust the contingent consideration to fair value with changes in fair value recognized in operating earnings. Changes in fair values reflect new information about the probability and timing of meeting the conditions of the milestone payments. In the absence of new information, changes in fair value will only reflect the interest component of contingent consideration related to the passage of time.

As of December 31, 2020, estimated future contingent milestone payments related to prior business combinations range from zero if no milestone events are achieved, to a maximum of $905.6 if all development, regulatory and sales-based milestones are reached. As of December 31, 2020, the fair value of acquisition-related contingent consideration was $414.3. During the next 12 months, we expect to make milestone payments of $120.0 associated with our prior business combinations. The following table represents a roll-forward of our acquisition-related contingent consideration:


	Year ended December 31, 2020
Balance as of December 31, 2019	$	192.4
Amounts issued	160.7
Changes in fair value	61.2
Balance as of December 31, 2020	$	414.3

Other Contingent Payments

In January 2019, we entered into an agreement with Caelum, a biotechnology company that is developing CAEL-101 for light chain (AL) amyloidosis. Under the terms of the agreement, we acquired a minority equity interest

in preferred stock of Caelum and an exclusive option to acquire the remaining equity in Caelum based on Phase II data, for pre-negotiated economics. We paid $30.0 during the first quarter 2019 and agreed to pay up to an additional $30.0 in contingent development milestones prior to our exercise of the option to acquire the remaining equity in Caelum. These contingent payments met the definition of a derivative liability and were initially recorded at fair value of $27.1, based on the probability-weighted cash flows, discounted using a cost of debt ranging from 3.3% to 3.5%.

In December 2019, following FDA feedback which resulted in the redesign and expansion of Caelum's planned clinical development program for CAEL-101, we amended the terms of our existing option agreement with Caelum. The amendment modified the terms of the option to acquire the remaining equity in Caelum based on data from the expanded Phase II/III trials. The amendment also modified the development-related milestone events associated with the initial $30.0 in contingent payments, provided for an additional $20.0 in upfront funding, as well as funding of $60.0 in exchange for an additional equity interest at fair value upon achievement of a specific development-related milestone event. As of December 31, 2019 and in connection with the amendment, we remeasured the derivative liability related to the initial $30.0 in contingent payments to its fair value, or $24.0, based on the probability-weighted cash flows, discounted using a cost of debt of 2.1% and accrued for the additional $20.0 in upfront funding. We paid the additional $20.0 in upfront funding and the initial $30.0 in contingent payments in 2020.

Each reporting period, we adjust the derivative liability associated with the contingent payments to fair value with changes in fair value recognized in other income and (expense). Changes in fair values reflect new information about the probability and anticipated timing of meeting the conditions of the milestone payments. In the absence of new information, changes in fair value will only reflect the interest component of the liability related to the passage of time. The aggregate $30.0 milestone payments made during 2020 settled the derivative liability and reduced the derivative liability balance to zero. We recorded $6.0 of expense in other income and (expense) during the year ended December 31, 2020. We recorded $3.1 of income in other income and (expense) during the year ended December 31, 2019, including $4.1 as a result of the amendment to our agreement with Caelum.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Restructuring and Related Expenses

12 Months Ended

Dec. 31, 2020

Restructuring and Related Activities [Abstract]

Restructuring and Related Expenses

During the third quarter 2020, we initiated restructuring activities primarily within our commercial organization as part of an initiative intended to redefine our operating model. The actions are intended to reallocate resources necessary to align our organization with our diversifying portfolio of new products and strategic objectives, and will include investments in digital capabilities, technologies and solutions to support a more virtual and digital customer experience and tailored to the markets in which we operate.

The actions are expected to be substantially completed during 2021, with the cumulative pretax costs to be incurred by the Company to implement the program estimated to be approximately $10.0, which has primarily been recognized during the year ended December 31, 2020. We expect that the pretax costs will primarily result in cash outlays, as the costs primarily relate to employee separation expenses.

In the first quarter 2019, we initiated corporate restructuring activities to re-align our international commercial organization through re-prioritization of certain geographical markets and to implement operational excellence through strategic reallocation of resources. Actions under the first quarter 2019 restructuring program have been completed.

In the first quarter 2017, we initiated a company-wide restructuring designed to help position the Company for sustainable, long-term growth that we believe will further allow us to fulfill our mission of serving patients and families with rare diseases. In September 2017, we committed to an operational plan to re-align the global organization with its refocused corporate strategy. The re-alignment included the relocation of the Company's headquarters to Boston, Massachusetts and a reduction of the Company's global workforce. The restructuring was designed to result in cost savings by focusing the development portfolio, simplifying business structures and process across the Company's global operations, and closing multiple Alexion sites. Costs incurred during 2018 relate to the 2017 restructuring plan. Actions under the 2017 restructuring programs have been completed.

The following table summarizes the total expenses recorded related to the restructuring activities by type of activity and the locations recognized within the consolidated statements of operations:


	December 31, 2020								December 31, 2019								December 31, 2018
	Employee Separation Costs		Asset-Related Charges		Other		Total		Employee Separation Costs		Asset-Related Charges		Other		Total		Employee Separation Costs		Asset-Related Charges		Other		Total
Cost of sales (exclusive of amortization of purchased intangible assets)	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	5.8	$	—	$	5.8
Research and development	—		—		—		—		—		—		—		—		—		0.1		—		0.1
Selling, general and administrative	—		—		—		—		—		—		—		—		—		19.4		—		19.4
Restructuring expenses	8.4		—		1.9		10.3		8.4		—		3.6		12.0		4.6		—		20.9		25.5
Other income and (expense)	—		—		—		—		—		—		—		—		—				(0.1)		(0.1)
	$	8.4	$	—	$	1.9	$	10.3	$	8.4	$	—	$	3.6	$	12.0	$	4.6	$	25.3	$	20.8	$	50.7

Employee separation costs are associated with headcount reductions.

Asset-related charges consist of accelerated depreciation costs and asset impairment charges. Accelerated depreciation costs primarily relates to site closures, including ARIMF (which was sold to a third-party in 2018). Accelerated depreciation costs represent the difference between the depreciation expense recognized over the revised useful life of the asset, based upon the anticipated date the site closure, and the depreciation expense as determined using the useful life prior to the restructuring activities. Asset impairment charges primarily related to manufacturing assets that will no longer be utilized due to the 2017 restructuring activities.

Other costs consist of contract termination expenses, relocation costs, and other costs incurred as a direct result of an exit plan.

The following table presents a reconciliation of the restructuring reserve recorded within accounts payable and accrued expenses on the Company's consolidated balance sheets for the years ended December 31, 2020 and 2019:


	December 31, 2020						December 31, 2019
	Employee Separation Costs		Other		Total		Employee Separation Costs		Other		Total
Liability, beginning of year	$	3.3	$	3.5	$	6.8	$	4.2	$	—	$	4.2
Charges	14.3		2.4		16.7		14.2		3.0		17.2
Settlements	(3.5)		(5.4)		(8.9)		(9.3)		(0.1)		(9.4)
Adjustments to previous estimates	(5.9)		(0.5)		(6.4)		(5.8)		0.6		(5.2)
Liability, end of year	$	8.2	$	—	$	8.2	$	3.3	$	3.5	$	6.8

The restructuring reserve of $8.2 and $6.8 is recorded in accounts payable and accrued expenses on the Company's consolidated balance sheet as of December 31, 2020 and 2019, respectively. The accrued amounts are expected to be paid in the next twelve months. We currently estimate incurring an immaterial amount of restructuring expenses in 2021 related to the third quarter 2020 action.

Segment Information

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Segment Information

We operate in a single segment, focusing on serving patients affected by rare diseases and devastating conditions through the discovery, development and commercialization of life-changing therapies. Consistent with our operational structure, our chief operating decision maker manages and allocates resources at a global, consolidated level. Therefore, results of our operations are reported on a consolidated basis for purposes of segment reporting, consistent with our management reporting. Disclosures about net product sales and long-lived assets by geographic area are presented below.

Net Product Sales

Net product sales by product and geographic region are as follows:


	Year Ended December 31,						% Change
	2020		2019		2018		2020 compared to 2019		2019 compared to 2018
SOLIRIS
United States	$	2,259.7	$	2,014.0	$	1,588.4	12.2	%	26.8	%
Europe	1,033.3		1,049.8		1,036.7		(1.6)	%	1.3	%
Asia Pacific	343.0		423.5		382.0		(19.0)	%	10.9	%
Rest of World	428.2		459.1		555.9		(6.7)	%	(17.4)	%
	$	4,064.2	$	3,946.4	$	3,563.0	3.0	%	10.8	%

ULTOMIRIS
United States	$	646.0	$	236.8	$	—	172.8	%	**
Europe	170.4		52.2		—		226.4	%	**
Asia Pacific	255.3		49.9		—		411.6	%	**
Rest of World	5.0		—		—		**		**
	$	1,076.7	$	338.9	$	—	**		**

STRENSIQ
United States	$	562.9	$	451.7	$	374.3	24.6	%	20.7	%
Europe	80.8		77.0		61.7		4.9	%	24.8	%
Asia Pacific	61.0		50.4		27.9		21.0	%	80.6	%
Rest of World	27.1		13.4		11.2		102.2	%	19.6	%
	$	731.8	$	592.5	$	475.1	23.5	%	24.7	%

ANDEXXA
United States	$	71.7	$	—	$	—	**		**
Europe	6.8		—		—		**		**
Asia Pacific	—		—		—		**		**
Rest of World	—		—		—		**		**
	$	78.5	$	—	$	—	**		**

KANUMA
United States	$	63.7	$	60.0	$	51.3	6.2	%	17.0	%
Europe	35.6		27.1		21.6		31.4	%	25.5	%
Asia Pacific	4.3		4.6		3.7		(6.5)	%	24.3	%
Rest of World	14.3		20.5		15.4		(30.2)	%	33.1	%
	$	117.9	$	112.2	$	92.0	5.1	%	22.0	%

Total Net Product Sales	$	6,069.1	$	4,990.0	$	4,130.1	21.6	%	20.8	%

** Percentages not meaningful

Long-Lived Assets

Long-lived assets consist of property, plant and equipment.


	December 31,
	2020		2019
United States	$	261.0	$	272.8
Europe	976.2		889.6
Other	1.6		0.9
	$	1,238.8	$	1,163.3

Quarterly Financial Information (unaudited)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information (unaudited)

The following condensed quarterly financial information is for the years ended December 31, 2020 and 2019:


	March 31			June 30			September 30		December 31
2020
Total revenues	$	1,444.8		$	1,444.6		$	1,588.7	$	1,591.8
Cost of sales (exclusive of amortization of purchased intangible assets) (A)	111.7			144.9			144.7		152.2
Gross profit	1,333.1			1,299.7			1,444.0		1,439.6
Operating expenses	637.6			2,669.9		(1)	759.1		817.5
Operating income (loss)	695.5			(1,370.2)		(1)	684.9		622.1
Net income (loss)	$	557.6		$	(1,068.1)	(1)	$	578.1	$	535.8
Earnings (loss) per common share:
Basic	$	2.52		$	(4.84)		$	2.64	$	2.45
Diluted	$	2.50		$	(4.84)		$	2.62	$	2.42

	March 31			June 30			September 30		December 31
2019
Total revenues	$	1,140.4		$	1,203.3		$	1,263.1	$	1,384.3
Cost of sales (exclusive of amortization of purchased intangible assets) (A)	85.8			99.2			95.2		114.3
Gross profit	1,054.6			1,104.1			1,167.9		1,270.0
Operating expenses	537.8			571.5			637.9		729.0
Operating income	516.8			532.6			530.0		541.0
Net income	$	587.9	(2)	$	459.8		$	467.6	$	889.0	(3)
Earnings per common share:
Basic	$	2.63		$	2.05		$	2.09	$	4.02
Diluted	$	2.61		$	2.04		$	2.08	$	4.00

(A) Gross profit is calculated as total revenues less cost of sales

(1) Included within operating expenses for the second quarter 2020, we recorded an impairment charge of $2,042.3 to write-down the KANUMA intangible asset to fair value. The KANUMA intangible asset impairment resulted in a deferred tax benefit of $377.3. Refer to Note 4, Intangible Assets and Goodwill for additional information.

(2) During the first quarter 2019, we recognized one-time tax benefits of $95.7 and $30.3 associated with a tax election made with respect to intellectual property of Wilson Therapeutics AB and a release of an existing valuation allowance, respectively. Refer to Note 12, Income Taxes for additional information.

(3) During the fourth quarter 2019, we recognized a one-time tax benefit of $382.2 related to an intra-entity asset transfer of certain intellectual property within our captive foreign partnership. Refer to Note 12, Income Taxes for additional information.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsIn January 2021, Alexion entered into a definitive asset purchase agreement with Rhythm Pharmaceuticals, Inc. (“Rhythm”) to acquire its Rare Pediatric Disease Priority Review Voucher (PRV) for $100.0. Alexion’s acquisition of Rhythm’s PRV is subject to the satisfaction of customary closing conditions and approval from relevant regulatory agencies, including the expiration or early termination of the applicable waiting period under the Hart-Scott Rodino Antitrust Improvements Act. Upon closing, we will make a $100.0 cash payment and we expect to capitalize the PRV as an acquired IPR&D intangible asset.

Business Overview and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Business Overview and Summary of Significant Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

Dividend Policy

Use of Estimates; Critical Accounting Estimates

Use of Estimates

The most significant areas involving estimates, judgments and assumptions used in the preparation of our consolidated financial statements are as follows:

•Revenue recognition;

•Contingent liabilities;

•Share-based compensation;

•Valuation of acquired assets, including goodwill, intangible assets and inventory;

•Valuation of contingent consideration; and

•Income taxes.

Foreign Currency Translation

Cash and Cash Equivalents

Fair Value of Financial Instruments

Marketable Securities

factors are included in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity.

Accounts Receivable

Concentration of Credit Risk

Inventories

Inventories are stated at the lower of cost or net realizable value. Cost is determined in a manner that approximates average costs.

The components of inventory are as follows:


	December 31,
	2020		2019
Raw materials	$	91.2	$	41.2
Work-in-process	260.8		180.8
Finished goods	510.3		405.6
	$	862.3	$	627.6

Balance Sheet Classification:
Inventories	$	775.7	$	627.6
Other assets	$	86.6	$	—

Capitalization of Inventory Costs

Inventory Write-Offs

Derivative Instruments

Property, Plant and Equipment

Property, plant and equipment are stated at cost and are depreciated on a straight-line basis over the estimated useful lives of the assets. We estimate economic lives as follows:

•Building and improvements—fifteen to thirty-five years

•Machinery and laboratory equipment—five to fifteen years

•Computer hardware and software—three to seven years

•Furniture and office equipment— five to ten years

Construction-in-progress reflects amounts incurred for property, plant, or equipment construction or improvements that have not been placed in service.We capitalize costs incurred for the construction of facilities which support commercial manufacturing. We also capitalize costs related to validation activities which are directly attributable to preparing the facility for its intended use, including engineering runs and inventory production necessary to obtain approval of the facility from government regulators for the production of a commercially approved drug. When the facility is substantially complete and ready

for its intended use and regulatory approval for commercial production has been received, we will place the asset in service.

Leases

Acquisitions

Our consolidated financial statements include the results of operations of an acquired business after the completion of the acquisition.

Intangible Assets

Our intangible assets generally consist of licensing rights, patents, purchased technology, acquired IPR&D and other intangibles. Intangible assets with definite lives are amortized based on their pattern of economic benefit over their estimated useful lives and reviewed periodically for impairment.Intangible assets related to IPR&D projects are considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts. During the period the assets are considered indefinite-lived, they will not be amortized but will be tested for impairment. Impairment testing is performed at least annually or when a triggering event occurs that could indicate a potential impairment. If and when development is complete, which generally occurs when regulatory approval to market a product is obtained, the associated assets are deemed finite-lived and are amortized over a period that best reflects the economic benefits provided by these assets.

Goodwill

Other Investments

Impairment of Long-Lived Assets

Contingent liabilities

Treasury Stock

Treasury stock is accounted for using the cost method, with the purchase price of the common stock recorded separately as a deduction from stockholders’ equity.

Revenue Recognition

Nature of Products

Variable Consideration

Variability in the transaction price for our products pursuant to our contracts with customers primarily arises from the following:

Refer to Note 18, Segment Information for a summary of revenue from contracts with customers by product and geographical region.

Contract Balances and Receivables

Research and Development Expenses

Share-Based Compensation

typically equals the vesting period. Compensation expense for awards with performance conditions is recognized using the graded-vesting method.

Restructuring and Restructuring Related Expenses

We record liabilities associated with one-time employee termination benefits and exit or disposal activities in the period in which the liability is incurred. One-time employee benefits are incurred when communicated to employees and / or where detailed action plans have been approved. For existing benefit arrangements, employee termination costs are accrued when the exit or disposal cost are probable and estimable. Costs for one-time termination benefits in which the employee is required to render service until termination in order to receive benefits are recognized ratably over the service period. Restructuring related expenses include accelerated depreciation costs and impairment charges associated with assets impacted by a restructuring exit activity. Accelerated depreciation costs represent the difference between the depreciation expense recognized over the revised useful life of the asset, based upon the anticipated date an impacted site closure, and the depreciation expense as determined using the useful life prior to the restructuring activities.

Earnings Per Common Share

Basic earnings per common share (EPS) is computed by dividing net income by the weighted-average number of shares of common stock outstanding. For purposes of calculating diluted EPS, the denominator reflects the potential dilution that could occur if stock options, unvested restricted stock units or other contracts to issue common stock were exercised or converted into common stock, using the treasury stock method.We exclude from EPS the weighted-average number of securities whose effect is anti-dilutive. Excluded from the calculation of EPS for the years ended December 31, 2020, 2019 and 2018 were 1.7, 3.0 and 2.8 shares of common stock, respectively, because their effect is anti-dilutive.

Income Taxes

Comprehensive Income

Reclassification

Certain items in the prior year’s consolidated financial statements have been reclassified to conform to the current presentation.

New Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Business Overview and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Business Overview and Summary of Significant Accounting Policies [Abstract]

Schedule of Inventories

The components of inventory are as follows:


	December 31,
	2020		2019
Raw materials	$	91.2	$	41.2
Work-in-process	260.8		180.8
Finished goods	510.3		405.6
	$	862.3	$	627.6

Balance Sheet Classification:
Inventories	$	775.7	$	627.6
Other assets	$	86.6	$	—

Schedule of the Calculation of Basic and Diluted EPS

The following table summarizes the calculation of basic and diluted EPS for years ended December 31, 2020, 2019 and 2018:


	Year Ended December 31,
	2020		2019		2018
Net income used for basic and diluted calculation	$	603.4	$	2,404.3	$	77.6
Shares used in computing earnings per common share—basic	220.1		223.2		222.7
Weighted-average effect of dilutive securities:
Stock awards	1.9		1.6		1.8
Shares used in computing earnings per common share—diluted	222.0		224.8		224.5
Earnings per common share:
Basic	$	2.74	$	10.77	$	0.35
Diluted	$	2.72	$	10.70	$	0.35

Acquisitions (Tables)

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Schedule of Business Acquisitions, by Acquisition

The following table summarizes the total consideration transferred to acquire Achillion and the estimated fair value of the identified assets acquired and liabilities assumed at the acquisition date:


Consideration
Upfront payment to shareholders and option holders	$	926.2
Upfront payment, fair value of equity compensation attributable to the post-combination service period	(20.0)
Upfront cash paid, net	906.2

Contingent consideration	160.7
Contingent consideration, fair value of equity compensation attributable to the post-combination service period	(5.7)
Total consideration	$	1,061.2

Assets Acquired and Liabilities Assumed
Cash and cash equivalents	$	68.5
Marketable securities	106.1
In-process research & development assets (IPR&D)	918.0
Goodwill	37.8
Deferred tax liabilities, net	(62.9)
Other assets and liabilities, net	(6.3)
Total net assets acquired	$	1,061.2

The following table summarizes the total consideration transferred to acquire Portola and the estimated fair value of the identified assets acquired and liabilities assumed at the acquisition date:


Consideration
Upfront payment to shareholders and equity holders	$	1,380.8
Upfront payment, fair value of equity compensation attributable to the post-combination service period	(11.1)
Upfront cash paid, net	1,369.7

Fair value of equity shares held by Alexion at closing	47.8
Fair value of replacement equity awards attributable to the pre-combination period	7.2
Total consideration to acquire outstanding equity, net	1,424.7

Total consideration to settle preexisting debt	196.9
Total consideration	$	1,621.6

Assets Acquired and Liabilities Assumed
Cash and cash equivalents	$	288.5
Marketable securities	17.8
Inventories, including noncurrent portion of $169.1 and validation batches of $60.9	362.5
Intangible assets	1,051.0
Goodwill	24.9
Deferred tax assets, net	116.6
Other assets	41.9
Accounts payable and accrued expenses	(75.6)
Long-term debt, including current portion of $7.7	(182.0)
Other liabilities	(24.0)
Total net assets acquired	$	1,621.6

Business Acquisition, Pro Forma Information


	Year ended December 31,
	2020		2019
Pro forma revenue	$	6,118.3	$	5,107.7
Pro forma net income	$	519.9	$	1,813.6

Business Combination, Separately Recognized Transactions


	Year ended December 31,
	2020		2019		2018
Transaction costs (1)	$	9.9	$	—	$	—
Integration costs	13.0		—		—
Fair value of equity compensation attributable to the post-combination service period	36.8		—		—
Employee separation costs (2)	57.9		—		—
	$	117.6	$	—	$	—

(1) Transaction costs primarily include legal fees related to the acquisition of Portola as well as costs incurred to effectuate the settlement of the Achillion outstanding options

Schedule Of Asset Acquisition, By Acquisition

The following table summarizes the total consideration for the acquisition and the value of assets acquired and liabilities assumed:


Consideration
Cash paid for acquisition of Wilson Therapeutics outstanding shares	$	749.3
Transaction costs	15.1
Total consideration	$	764.4

Assets Acquired and Liabilities Assumed
Cash	$	45.1
In-process research & development	803.7
Employee related liabilities	(71.4)
Other assets and liabilities	(13.0)
Total net assets acquired	$	764.4

The following table summarizes the total consideration for the acquisition and the value of the assets acquired and liabilities assumed:


Consideration
Upfront payment for acquisition of Syntimmune outstanding shares	$	400.0
Cash acquired	4.2
Working capital adjustment	2.3
Transaction costs	0.9
Total consideration	$	407.4

Assets Acquired and Liabilities Assumed
Cash	$	4.2
In-process research & development	375.2
Deferred tax assets	25.1
Other assets and liabilities	2.9
Total net assets acquired	$	407.4

Property, Plant and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment, Net [Abstract]

Schedule of Property, Plant and Equipment

A summary of property, plant and equipment is as follows:


	December 31, 2020		December 31, 2019
Land	$	9.6	$	9.6
Buildings and improvements	216.7		208.7
Machinery and laboratory equipment	134.1		126.0
Computer hardware and software	171.9		155.1
Furniture and office equipment	24.9		23.4
Construction-in-progress	828.7		734.2
Financing lease right of use assets	127.2		127.2
	1,513.1		1,384.2
Less: Accumulated depreciation and amortization	(274.3)		(220.9)
	$	1,238.8	$	1,163.3

Intangible Assets and Goodwill (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets and Goodwill

The following table summarizes the carrying amount of our intangible assets and goodwill, net of accumulated amortization:


		December 31, 2020							December 31, 2019
	Estimated Life (years)	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization		Net
Licensing Rights	3-8	$	57.0	$	(38.5)		$	18.5	$	57.0	$	(34.7)	$	22.3
Patents	7	10.5		(10.5)			—		10.5		(10.5)		—
Purchased technology	6-16	5,746.5		(3,684.7)		(a)	2,061.8		4,710.5		(1,388.7)		3,321.8
Other Intangibles	5	0.4		(0.3)			0.1		0.4		(0.2)		0.2
Acquired IPR&D	Indefinite	922.0		—			922.0		—		—		—
Total		$	6,736.4	$	(3,734.0)		$	3,002.4	$	4,778.4	$	(1,434.1)	$	3,344.3
Goodwill	Indefinite	$	5,103.0	$	(2.9)		$	5,100.1	$	5,040.3	$	(2.9)	$	5,037.4
(a) Includes an impairment charge of $2,042.3 recognized during the second quarter related to the KANUMA intangible asset

Schedule of Goodwill

The following summarizes the changes in the carrying amount of goodwill:


	December 31, 2020
Balance as of December 31, 2019	$	5,037.4
Goodwill resulting from the acquisitions of Achillion and Portola	62.7
Balance as of December 31, 2020	$	5,100.1

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Realized Gain (Loss) on Investments


	Year ended December 31,
	2020		2019		2018
Proceeds from maturities and sales (1)	$	1,042.5	$	2,832.8	$	10,196.8
Realized gains	$	—	$	—	$	1.1
Realized losses	$	—	$	—	$	0.4
(1) Proceeds from maturities and sales of available-for-sale debt securities include securities previously classified as cash and cash equivalents and marketable securities in the consolidated balance sheet

Schedule of Available-for-sale Securities Reconciliation

The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security as of December 31, 2019 were as follows:


	December 31, 2019
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
Commercial paper	$	246.9	$	—	$	—	$	246.9
Corporate bonds	24.3		—		—		24.3
Other government related obligations:
U.S.	70.4		—		—		70.4
Bank certificates of deposit	27.4		—		—		27.4
Total available-for-sale debt securities	$	369.0	$	—	$	—	$	369.0

Available-for-sale Securities by Balance Sheet Location Classification

The fair values of available-for-sale debt securities by classification in the consolidated balance sheet were as follows:


	December 31, 2020		December 31, 2019
Cash and cash equivalents	$	—	$	328.1
Marketable securities	—		40.9
	$	—	$	369.0

Derivative Instruments and Hedging Activities (Tables)

12 Months Ended

Dec. 31, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Interest Rate Derivatives [Table Text Block]

The following table summarizes the total interest rate swap contracts executed as of December 31, 2020:

Type of Interest Rate Swap

Notional Amount

Effective Date

Termination Date

Fixed Interest Rate or Rate Range

Floating to Fixed

$450.0

December 2018

December 2022

2.60% - 2.79%

Floating to Fixed

$1,300.0

December 2019

December 2022

2.37% - 2.83%

Schedule of Other Comprehensive Income and Earnings from Foreign Exchange Contracts


	Year ended December 31,
	2020				2019				2018
Financial Statement Line Item in which the Effects of Cash Flow Hedges are Recorded	Net Product Sales		Interest Expense		Net Product Sales		Interest Expense		Net Product Sales		Interest Expense
Total amount presented in the Consolidated Statements of Operations	$	6,069.1	$	(104.7)	$	4,990.0	$	(77.8)	$	4,130.1	$	(98.2)
Impact of cash flow hedging relationships:
Foreign exchange forward contracts	$	4.7	$	—	$	36.8	$	—	$	(1.8)	$	—
Interest rate swap contracts	$	—	$	(37.5)	$	—	$	13.3	$	—	$	13.6


	Year Ended December 31,
	2020		2019		2018
Foreign Exchange Forward Contracts:
(Loss) gain recognized in AOCI, net of tax	$	(36.4)	$	27.9	$	37.7
Gain (loss) reclassified from AOCI to net product sales, net of tax	$	3.6	$	28.4	$	(1.4)
Interest Rate Swap Contracts:
Loss recognized in AOCI, net of tax	$	(52.3)	$	(39.0)	$	(4.8)
(Loss) gain reclassified from AOCI to interest expense, net of tax	$	(29.1)	$	10.2	$	10.8

Schedule of Fair Value of Outstanding Derivatives

The following tables summarize the fair value of outstanding derivatives as of December 31, 2020 and 2019:

December 31, 2020

Asset Derivatives

Liability Derivatives

Balance Sheet
Location

Fair
Value

Balance Sheet
Location

Fair
Value

Derivatives designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

—

Other current liabilities

44.3

Foreign exchange forward contracts

Other assets

—

Other liabilities

1.2

Interest rate contracts

Prepaid expenses and other current assets

—

Other current liabilities

45.9

Interest rate contracts

Other assets

—

Other liabilities

45.4

Derivatives not designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

26.1

Other current liabilities

35.8

Total fair value of derivative instruments

26.1

172.6

December 31, 2019

Asset Derivatives

Liability Derivatives

Balance Sheet
Location

Fair
Value

Balance Sheet
Location

Fair
Value

Derivatives designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

12.7

Other current liabilities

6.2

Foreign exchange forward contracts

Other assets

0.6

Other liabilities

1.1

Interest rate contracts

Prepaid expenses and other current assets

—

Other current liabilities

19.5

Interest rate contracts

Other assets

—

Other liabilities

41.9

Derivatives not designated as hedging instruments:

Foreign exchange forward contracts

Prepaid expenses and other current assets

17.2

Other current liabilities

20.4

Total fair value of derivative instruments

30.5

89.1

Offsetting Assets and Liabilities [Table Text Block]

The following tables summarize the potential effect on our consolidated balance sheets of offsetting our foreign exchange forward contracts and interest rate contracts subject to such provisions:


December 31, 2020
							Gross Amounts Not Offset in the Consolidated Balance Sheet
Description	Gross Amounts of Recognized Assets/Liabilities		Gross Amounts Offset in the Consolidated Balance Sheet		Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheet		Derivative Financial Instruments		Cash Collateral Received (Pledged)		Net Amount
Derivative assets	$	26.1	$	—	$	26.1	$	(26.1)	$	—	$	—
Derivative liabilities	$	(172.6)	$	—	$	(172.6)	$	26.1	$	—	$	(146.5)


December 31, 2019
							Gross Amounts Not Offset in the Consolidated Balance Sheet
Description	Gross Amounts of Recognized Assets/Liabilities		Gross Amounts Offset in the Consolidated Balance Sheet		Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheet		Derivative Financial Instruments		Cash Collateral Received (Pledged)		Net Amount
Derivative assets	$	30.5	$	—	$	30.5	$	(21.4)	$	—	$	9.1
Derivative liabilities	$	(89.1)	$	—	$	(89.1)	$	21.4	$	—	$	(67.7)

Accounts Payable and Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2020

Accrued Liabilities [Abstract]

Schedule of Accrued Expenses

Accounts payable and accrued expenses consist of the following:


	December 31, 2020		December 31, 2019
Accounts payable	$	118.6	$	74.0
Royalties	27.6		20.1
Payroll and employee benefits	242.3		187.5
Taxes payable	150.9		103.9
Rebates payable	333.3		250.1
Clinical	97.0		67.3
Manufacturing	58.2		72.8
Accrued severance and restructuring costs	31.7		12.8
Other	143.7		178.2
	$	1,203.3	$	966.7

Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Debt

Our payment obligations for HCR royalty-based debt are as follows:


	Year ended December 31, 2020
Total repayment obligation as of the acquisition date	$	276.9
Less: interest to be accreted in future periods	(84.9)
Less: payments made	(5.0)
Carrying value as of December 31, 2020	$	187.0

Schedule of Maturities of Long-term Debt

The contractual maturities of our Credit Agreement and estimated royalty-based debt obligations due subsequent to December 31, 2020 are as follows:


Year
2021	$	146.1
2022	158.4
2023	2,167.7
2024	63.6
2025	76.5
Thereafter	43.5

Leases (Tables)

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Schedule of Lease Assets and Lease Liabilities

The following table summarizes our lease assets and liabilities as of December 31, 2020:


ROU Assets and Liabilities
	Balance Sheet Location	Financing		Operating
ROU - Asset	Right of use operating assets	$	—	$	223.1
ROU - Asset	Property, plant, and equipment	105.4		—
Lease liabilities (current)	Other current liabilities	5.6		28.1
Lease liabilities (noncurrent)	Noncurrent operating lease liabilities	—		177.1
Lease liabilities (noncurrent)	Other liabilities	67.3		—

The following table summarizes our lease assets and liabilities as of December 31, 2019:


ROU Assets and Liabilities
	Balance Sheet Location	Financing		Operating
ROU - Asset	Right of use operating assets	$	—	$	204.0
ROU - Asset	Property, plant, and equipment	116.3		—
Lease liabilities (current)	Other current liabilities	5.2		18.8
Lease liabilities (noncurrent)	Noncurrent operating lease liabilities	—		164.1
Lease liabilities (noncurrent)	Other liabilities	72.9		—

Summary of Lease Costs

The following table summarizes our lease related costs for the years ended December 31, 2020 and 2019:


Lease Cost:
	Statement of Operations Location	Years ended
		December 31, 2020		December 31, 2019
Financing Lease Cost		$	14.5	$	14.8
Amortization of ROU Assets	Operating Expenses	10.9		10.9
Interest on Lease Liabilities	Interest Expense	3.6		3.9
Operating Lease Cost	Operating Expenses	38.1		34.3
Variable Lease Cost	Operating Expenses	8.7		11.8
Total Lease Cost		$	61.3	$	60.9

Schedule of Lease Cash Flow Information

The following table summarizes supplemental cash flow information for the years ended December 31, 2020 and 2019:


Other Information
	Years ended
	December 31, 2020		December 31, 2019
Cash Paid For Amounts Included In Measurement of Liabilities	$	39.4	$	32.3
Operating Cash Flows From Financing Leases	3.6		3.9
Operating Cash Flows From Operating Leases	30.7		23.5
Financing Cash Flows From Financing Leases	5.1		4.9
ROU Assets Obtained In Exchange For New Financing Liabilities (1)	—		—
ROU Assets Obtained In Exchange For New Operating Liabilities (2)	31.6		27.5

(1) We capitalized $83.1 of ROU financing assets upon adoption of the new lease standard in the first quarter of 2019 that are excluded from the figures for the year ended December 31, 2019. This figure excludes $44.2 of opening adjustments to ROU finance assets related, primarily, to prepayments of rent.
(2) We capitalized $172.2 of ROU operating assets upon adoption of the new lease standard in the first quarter of 2019 that are excluded from the figures for the year ended December 31, 2019. This figure excludes $26.6 of opening adjustments to ROU operating assets related, primarily, to prepayments of rent.

Schedule of Financing Lease Liability Maturities

The following tables summarize maturities of lease liabilities and the reconciliation of lease liabilities as of December 31, 2020:


Lease Liability Maturity Summary
Year	Financing		Operating		Total
2021	$	9.0	$	34.4	$	43.4
2022	9.2		32.0		41.2
2023	9.2		25.2		34.4
2024	9.4		22.5		31.9
2025	9.6		20.7		30.3
Thereafter	45.0		103.1		148.1

The following table summarizes the reconciliation of lease liabilities as of December 31, 2019:

Schedule of Operating Lease Liability Maturities

The following tables summarize maturities of lease liabilities and the reconciliation of lease liabilities as of December 31, 2020:


Lease Liability Maturity Summary
Year	Financing		Operating		Total
2021	$	9.0	$	34.4	$	43.4
2022	9.2		32.0		41.2
2023	9.2		25.2		34.4
2024	9.4		22.5		31.9
2025	9.6		20.7		30.3
Thereafter	45.0		103.1		148.1

The following table summarizes the reconciliation of lease liabilities as of December 31, 2019:

Schedule of Operating and Finance Lease Additional Information


Reconciliation of Lease Liabilities:	Financing			Operating			Total
Weighted-average Remaining Lease Term (years)	9.67			8.87			9.08
Weighted-average Discount Rate	4.9		%	3.4		%	3.8		%

Total Undiscounted Lease Liability	$	91.4		$	237.9		$	329.3
Imputed Interest	18.5			32.7			51.2
Total Discounted Lease Liability	72.9			205.2			278.1


Reconciliation of Lease Liabilities:	Financing			Operating			Total
Weighted-average Remaining Lease Term (years)	10.67			10.17			10.32
Weighted-average Discount Rate	4.9		%	4.1		%	4.3		%

Total Undiscounted Lease Liability	$	100.2		$	223.6		$	323.8
Imputed Interest	22.1			40.7			62.8
Total Discounted Lease Liability	78.1			182.9			261.0

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Income Tax Provision (Benefit) on Income Before Income Taxes

Income tax expense is based on income before income taxes as follows:


	Year Ended December 31,
	2020		2019		2018
U.S.	$	(1,098.5)	$	2.0	$	(451.4)
Non-U.S.	1,667.5		2,176.8		693.6
	$	569.0	$	2,178.8	$	242.2

Schedule of Components of Income Tax Provision (Benefit)

The components of income tax expense are as follows:


	Year Ended December 31,
	2020		2019		2018
Domestic
Current	$	3.1	$	71.8	$	57.0
Deferred	(382.1)		1,731.0		49.5
	(379.0)		1,802.8		106.5
Foreign
Current	245.9		158.2		74.7
Deferred	98.7		(2,186.5)		(16.6)
	344.6		(2,028.3)		58.1
Total
Current	249.0		230.0		131.7
Deferred	(283.4)		(455.5)		32.9
	$	(34.4)	$	(225.5)	$	164.6

Reconciliation of the Statutory U.S. Federal Income Tax Rate to Effective Income Tax Rate

The reconciliation of the statutory U.S. federal income tax rate to our effective income tax rate is as follows:


	Year Ended December 31,
	2020		2019		2018
U.S. federal statutory tax rate	21.0	%	21.0	%	21.0	%
Benefit of foreign earnings	(15.5)	%	(12.6)	%	(71.2)	%
Tax credits	(7.3)	%	(0.7)	%	(17.0)	%
Tax reserves	(0.6)	%	(0.1)	%	12.1	%
Acquired in-process research & development	—	%	—	%	102.6	%
Intra-entity asset transfer of intellectual property	0.4	%	(17.5)	%	—	%
Foreign-derived intangible income	(10.0)	%	(1.6)	%	(4.5)	%
U.S. state taxes	(1.6)	%	0.7	%	14.2	%
IRC 162(m) executive compensation	4.1	%	0.2	%	2.2	%
Other permanent differences	3.5	%	0.3	%	8.6	%

Effective Income Tax Rate	(6.0)	%	(10.3)	%	68.0	%

Schedule of Components of Deferred Tax Assets and Liabilities

The components of the deferred tax assets and liabilities are as follows:


	December 31,		December 31,
	2020		2019
Deferred tax assets:
Net operating losses	$	318.1	$	102.9
Income tax credits	465.1		328.1
Stock compensation	58.6		57.1
Accruals and allowances	138.8		65.2
Unrealized losses	25.4		18.8
Research and development expenses	1.9		3.5
Accrued royalties	1.2		0.8
ROU leases	45.8		46.2
Intangible assets	1,892.0		1,967.3
	2,946.9		2,589.9
Valuation allowance	(276.0)		(72.6)
Total deferred tax assets	2,670.9		2,517.3
Deferred tax liabilities:
Depreciable assets	(5.6)		(5.1)
Inventory fair value step-up	(53.5)		—
Investment in foreign partnership	(1,992.7)		(2,249.5)
ROU leases	(51.9)		(53.9)
Total deferred tax liabilities	(2,103.7)		(2,308.5)
Net deferred tax (liability) asset	$	567.2	$	208.8

Summary of Valuation Allowance

The following table represents a roll-forward of our valuation allowance on deferred tax assets:


	Valuation Allowance on Deferred Tax Assets
Balances, December 31, 2017	$	(3.4)
Additions charged to income tax expense	—
Additions charged to acquired in-process research and development	(17.1)
Reductions credited to income tax expense	0.9
Balances, December 31, 2018	$	(19.6)
Additions charged to income tax expense	(68.6)
Reductions credited to income tax expense	15.6
Balances, December 31, 2019	$	(72.6)
Additions charged to income tax expense	(18.8)
Additions charged to goodwill	(184.6)
Reductions credited to income tax expense	—
Balances, December 31, 2020	$	(276.0)

Reconciliation of Unrecognized Tax Benefits

The beginning and ending amounts of unrecognized tax benefits reconciles as follows:


	2020		2019		2018
Beginning of period balance	$	133.8	$	92.7	$	60.9
Increases for tax positions taken during a prior period	27.6		3.4		9.1
Decreases for tax positions taken during a prior period	(10.0)		(4.9)		(5.8)
Increases for tax positions taken during the current period	28.0		43.8		28.8
Decreases for tax positions related to settlements	(13.9)		—		—
Decreases for tax positions related to lapse of statute	(2.1)		(1.2)		(0.3)
	$	163.4	$	133.8	$	92.7

Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity

A summary of the status of our stock options as of December 31, 2020, and changes during the year then ended is presented in the table and narrative below:


	Number of shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2019	3.0	$	119.51
Granted	—	75.10
Exercised	(0.7)	64.79
Forfeited and canceled	(0.1)	146.19
Outstanding as of December 31, 2020	2.2	$	134.15	3.52	$	67.3
Vested and unvested expected to vest as of December 31, 2020	2.2	$	134.15	3.52	$	67.2
Exercisable as of December 31, 2020	2.2	$	134.35	3.49	$	66.3

Schedule of Share-based Compensation, Restricted Stock Activity

A summary of the status of our nonvested Restricted Stock as of December 31, 2020 and changes during the year then ended is as follows:


	Number of Shares	Weighted Average Grant Date Fair Value
Nonvested Restricted Stock as of December 31, 2019	4.3	$	128.24
Shares granted	3.9	100.95
Shares forfeited	(0.6)	119.07
Shares vested	(2.2)	122.86
Nonvested Restricted Stock as of December 31, 2020	5.4	$	111.54

Schedule of Share-Based Compensation

The following table summarizes the share-based compensation expense in the consolidated statements of operations:


	Year Ended December 31,
	2020		2019		2018
Cost of sales (exclusive of amortization of purchased intangible assets)	$	12.4	$	14.1	$	16.0
Research and development	68.6		61.8		57.5
Selling, general and administrative	179.7		161.1		129.5
Acquisition-related costs	20.4		—		—
Total share-based compensation expense	281.1		237.0		203.0
Income tax effect	(65.3)		(55.0)		(46.5)
Total share-based compensation expense, net of tax	$	215.8	$	182.0	$	156.5

Other Comprehensive Income and Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2020

Other Comprehensive Income and Accumulated Other Comprehensive Income [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

The following table summarizes the changes in AOCI, by component, for the years ended December 31, 2020, 2019 and 2018:


	Defined Benefit Pension Plans		Unrealized Gains (Losses) from Debt Securities		Unrealized Gains (Losses) from Hedging Activities		Foreign Currency Translation Adjustment		Total Accumulated Other Comprehensive Income (Loss)
Balances, December 31, 2017	$	(4.8)	$	0.2	$	(13.9)	$	(15.9)	$	(34.4)
Other comprehensive income (loss) before reclassifications	1.5		0.1		32.9		(0.5)		34.0
Amounts reclassified from other comprehensive income	0.7		(0.6)		(9.4)		—		(9.3)
Net other comprehensive income (loss)	2.2		(0.5)		23.5		(0.5)		24.7
Balances, December 31, 2018	$	(2.6)	$	(0.3)	$	9.6	$	(16.4)	$	(9.7)
Other comprehensive income (loss) before reclassifications	(6.6)		0.2		(11.1)		(1.0)		(18.5)
Amounts reclassified from other comprehensive income	—		—		(38.6)		—		(38.6)
Net other comprehensive income (loss)	(6.6)		0.2		(49.7)		(1.0)		(57.1)
Balances, December 31, 2019	$	(9.2)	$	(0.1)	$	(40.1)	$	(17.4)	$	(66.8)
Other comprehensive income (loss) before reclassifications	(1.5)		0.1		(88.1)		5.7		(83.8)
Amounts reclassified from other comprehensive income	0.5		—		25.5		—		26.0
Net other comprehensive income (loss)	(1.0)		0.1		(62.6)		5.7		(57.8)
Balances, December 31, 2020	$	(10.2)	$	—	$	(102.7)	$	(11.7)	$	(124.6)

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

The table below provides details regarding significant reclassifications from AOCI during the years ended December 31, 2020, 2019 and 2018:


Details about Accumulated Other Comprehensive Income Components	Amount Reclassified From Accumulated Other Comprehensive Income during the year ended December 31,						Affected Line Item in the Consolidated Statements of Operations
	2020		2019		2018
Unrealized Gains (Losses) on Hedging Activity
Forward exchange forward contracts	$	4.7	$	36.8	$	(1.8)	Net product sales
Interest rate swap contracts	(37.5)		13.3		13.6		Interest expense
	(32.8)		50.1		11.8
	7.3		(11.5)		(2.4)		Income tax (benefit) expense
	$	(25.5)	$	38.6	$	9.4

Defined Benefit Pension Items
Amortization of prior service costs and actuarial losses	$	(0.7)	$	—	$	(0.3)
Curtailment	—		—		(0.6)
	(0.7)		—		(0.9)
	0.2		—		0.2		Income tax (benefit) expense
	$	(0.5)	$	—	$	(0.7)

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule Of Assets And Liabilites Measured At Fair Value


		Fair Value Measurement at December 31, 2020
Balance Sheet Classification	Type of Instrument	Total		Level 1		Level 2		Level 3
Cash equivalents	Money market funds	$	833.7	$	—	$	833.7	$	—





Marketable securities	Mutual funds	$	34.9	$	34.9	$	—	$	—





Other assets	Equity securities	$	143.2	$	122.7	$	20.5	$	—
Prepaid expenses and other current assets	Foreign exchange forward contracts	$	26.1	$	—	$	26.1	$	—

Other current liabilities	Foreign exchange forward contracts	$	80.1	$	—	$	80.1	$	—
Other liabilities	Foreign exchange forward contracts	$	1.2	$	—	$	1.2	$	—


Other current liabilities	Interest rate contracts	$	45.9	$	—	$	45.9	$	—
Other liabilities	Interest rate contracts	$	45.4	$	—	$	45.4	$	—
Current portion of contingent consideration	Acquisition-related contingent consideration	$	114.9	$	—	$	—	$	114.9
Contingent consideration	Acquisition-related contingent consideration	$	299.4	$	—	$	—	$	299.4


		Fair Value Measurement at December 31, 2019
Balance Sheet Classification	Type of Instrument	Total		Level 1		Level 2		Level 3
Cash equivalents	Money market funds	$	635.9	$	—	$	635.9	$	—
Cash equivalents	Commercial paper	$	227.9	$	—	$	227.9	$	—
Cash equivalents	Corporate bonds	$	20.6	$	—	$	20.6	$	—
Cash equivalents	Bank certificates of deposit	$	19.2	$	—	$	19.2	$	—
Cash equivalents	Other government-related obligations	$	60.4	$	—	$	60.4	$	—
Marketable securities	Mutual funds	$	23.1	$	23.1	$	—	$	—
Marketable securities	Commercial paper	$	19.0	$	—	$	19.0	$	—
Marketable securities	Corporate bonds	$	3.7	$	—	$	3.7	$	—
Marketable securities	Other government-related obligations	$	10.0	$	—	$	10.0	$	—
Marketable securities	Bank certificates of deposit	$	8.2	$	—	$	8.2	$	—
Other assets	Equity securities	$	79.0	$	51.2	$	27.8	$	—
Prepaid expenses and other current assets	Foreign exchange forward contracts	$	29.9	$	—	$	29.9	$	—
Other assets	Foreign exchange forward contracts	$	0.6	$	—	$	0.6	$	—
Other current liabilities	Foreign exchange forward contracts	$	26.6	$	—	$	26.6	$	—
Other liabilities	Foreign exchange forward contracts	$	1.1	$	—	$	1.1	$	—
Other current liabilities	Interest rate contracts	$	19.5	$	—	$	19.5	$	—
Other liabilities	Interest rate contracts	$	41.9	$	—	$	41.9	$	—
Contingent consideration	Acquisition-related contingent consideration	$	192.4	$	—	$	—	$	192.4
Other current liabilities	Other contingent payments	$	24.0	$	—	$	—	$	24.0

Schedule Of Acquisition-Related Contingent Consideration

The following table represents a roll-forward of our acquisition-related contingent consideration:


	Year ended December 31, 2020
Balance as of December 31, 2019	$	192.4
Amounts issued	160.7
Changes in fair value	61.2
Balance as of December 31, 2020	$	414.3

Restructuring and Related Expenses (Tables)

12 Months Ended

Dec. 31, 2020

Restructuring and Related Activities [Abstract]

Restructuring and Related Costs

The following table summarizes the total expenses recorded related to the restructuring activities by type of activity and the locations recognized within the consolidated statements of operations:


	December 31, 2020								December 31, 2019								December 31, 2018
	Employee Separation Costs		Asset-Related Charges		Other		Total		Employee Separation Costs		Asset-Related Charges		Other		Total		Employee Separation Costs		Asset-Related Charges		Other		Total
Cost of sales (exclusive of amortization of purchased intangible assets)	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	5.8	$	—	$	5.8
Research and development	—		—		—		—		—		—		—		—		—		0.1		—		0.1
Selling, general and administrative	—		—		—		—		—		—		—		—		—		19.4		—		19.4
Restructuring expenses	8.4		—		1.9		10.3		8.4		—		3.6		12.0		4.6		—		20.9		25.5
Other income and (expense)	—		—		—		—		—		—		—		—		—				(0.1)		(0.1)
	$	8.4	$	—	$	1.9	$	10.3	$	8.4	$	—	$	3.6	$	12.0	$	4.6	$	25.3	$	20.8	$	50.7


	December 31, 2020						December 31, 2019
	Employee Separation Costs		Other		Total		Employee Separation Costs		Other		Total
Liability, beginning of year	$	3.3	$	3.5	$	6.8	$	4.2	$	—	$	4.2
Charges	14.3		2.4		16.7		14.2		3.0		17.2
Settlements	(3.5)		(5.4)		(8.9)		(9.3)		(0.1)		(9.4)
Adjustments to previous estimates	(5.9)		(0.5)		(6.4)		(5.8)		0.6		(5.2)
Liability, end of year	$	8.2	$	—	$	8.2	$	3.3	$	3.5	$	6.8

Segment Information (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Schedule of Revenues and Tangible Long-Lived Assets by Significant Geographic Region

Net product sales by product and geographic region are as follows:


	Year Ended December 31,						% Change
	2020		2019		2018		2020 compared to 2019		2019 compared to 2018
SOLIRIS
United States	$	2,259.7	$	2,014.0	$	1,588.4	12.2	%	26.8	%
Europe	1,033.3		1,049.8		1,036.7		(1.6)	%	1.3	%
Asia Pacific	343.0		423.5		382.0		(19.0)	%	10.9	%
Rest of World	428.2		459.1		555.9		(6.7)	%	(17.4)	%
	$	4,064.2	$	3,946.4	$	3,563.0	3.0	%	10.8	%

ULTOMIRIS
United States	$	646.0	$	236.8	$	—	172.8	%	**
Europe	170.4		52.2		—		226.4	%	**
Asia Pacific	255.3		49.9		—		411.6	%	**
Rest of World	5.0		—		—		**		**
	$	1,076.7	$	338.9	$	—	**		**

STRENSIQ
United States	$	562.9	$	451.7	$	374.3	24.6	%	20.7	%
Europe	80.8		77.0		61.7		4.9	%	24.8	%
Asia Pacific	61.0		50.4		27.9		21.0	%	80.6	%
Rest of World	27.1		13.4		11.2		102.2	%	19.6	%
	$	731.8	$	592.5	$	475.1	23.5	%	24.7	%

ANDEXXA
United States	$	71.7	$	—	$	—	**		**
Europe	6.8		—		—		**		**
Asia Pacific	—		—		—		**		**
Rest of World	—		—		—		**		**
	$	78.5	$	—	$	—	**		**

KANUMA
United States	$	63.7	$	60.0	$	51.3	6.2	%	17.0	%
Europe	35.6		27.1		21.6		31.4	%	25.5	%
Asia Pacific	4.3		4.6		3.7		(6.5)	%	24.3	%
Rest of World	14.3		20.5		15.4		(30.2)	%	33.1	%
	$	117.9	$	112.2	$	92.0	5.1	%	22.0	%

Total Net Product Sales	$	6,069.1	$	4,990.0	$	4,130.1	21.6	%	20.8	%

** Percentages not meaningful

Long-lived assets consist of property, plant and equipment.


	December 31,
	2020		2019
United States	$	261.0	$	272.8
Europe	976.2		889.6
Other	1.6		0.9
	$	1,238.8	$	1,163.3

Quarterly Financial Information (unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Schedule of Condensed Quarterly Financial Information

The following condensed quarterly financial information is for the years ended December 31, 2020 and 2019:


	March 31			June 30			September 30		December 31
2020
Total revenues	$	1,444.8		$	1,444.6		$	1,588.7	$	1,591.8
Cost of sales (exclusive of amortization of purchased intangible assets) (A)	111.7			144.9			144.7		152.2
Gross profit	1,333.1			1,299.7			1,444.0		1,439.6
Operating expenses	637.6			2,669.9		(1)	759.1		817.5
Operating income (loss)	695.5			(1,370.2)		(1)	684.9		622.1
Net income (loss)	$	557.6		$	(1,068.1)	(1)	$	578.1	$	535.8
Earnings (loss) per common share:
Basic	$	2.52		$	(4.84)		$	2.64	$	2.45
Diluted	$	2.50		$	(4.84)		$	2.62	$	2.42

	March 31			June 30			September 30		December 31
2019
Total revenues	$	1,140.4		$	1,203.3		$	1,263.1	$	1,384.3
Cost of sales (exclusive of amortization of purchased intangible assets) (A)	85.8			99.2			95.2		114.3
Gross profit	1,054.6			1,104.1			1,167.9		1,270.0
Operating expenses	537.8			571.5			637.9		729.0
Operating income	516.8			532.6			530.0		541.0
Net income	$	587.9	(2)	$	459.8		$	467.6	$	889.0	(3)
Earnings per common share:
Basic	$	2.63		$	2.05		$	2.09	$	4.02
Diluted	$	2.61		$	2.04		$	2.08	$	4.00

(A) Gross profit is calculated as total revenues less cost of sales

Business Overview and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended									12 Months Ended
	Dec. 12, 2020	Jul. 02, 2020	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Overview And Summary Of Significant Accounting Policies
Common stock, par value				$ 0.0001				$ 0.0001				$ 0.0001	$ 0.0001
Inventories				$ 862.3				$ 627.6				$ 862.3	$ 627.6
Decrease in property, plant and equipment and other assets				(1,513.1)				(1,384.2)				(1,513.1)	(1,384.2)
Right of use operating assets				223.1				204.0				223.1	204.0
Operating Lease, Liability				205.2				182.9				205.2	182.9
Increase (decrease) in retained earnings				5,243.2				4,639.8				5,243.2	4,639.8
Impairment of intangible assets												2,053.3	0.0	$ 0.0
Total revenues				1,591.8	$ 1,588.7	$ 1,444.6	$ 1,444.8	1,384.3	$ 1,263.1	$ 1,203.3	$ 1,140.4	6,069.9	4,991.1	4,131.2
Net income				535.8	$ 578.1	(1,068.1)	$ 557.6	889.0	$ 467.6	$ 459.8	587.9	$ 603.4	$ 2,404.3	$ 77.6
Purchase per share of fair market value of common stock (percent) (lower of)												85.00%
ESPP, discount (percent)												15.00%
Acquired IPRD
Business Overview And Summary Of Significant Accounting Policies
Impairment of intangible assets												$ 11.0
Impairment of indefinite-lived intangible assets						$ 11.0
Purchased technology
Business Overview And Summary Of Significant Accounting Policies
Impairment of indefinite-lived intangible assets												$ 2,042.3
AstraZeneca
Business Overview And Summary Of Significant Accounting Policies
Common stock, par value	$ 0.0001
Right to receive depositary shares (shares)	2.1243
Consideration transferred per share (in dollars per share)	$ 60.00
Merger payment	$ 1,180.0
Payment if merger is terminated	270.0
AstraZeneca \| Forecast
Business Overview And Summary Of Significant Accounting Policies
Ownership percentage of combined company			15.00%
AstraZeneca \| AstraZeneca
Business Overview And Summary Of Significant Accounting Policies
Payment if merger is terminated	$ 1,415.0
Portola
Business Overview And Summary Of Significant Accounting Policies
Consideration transferred per share (in dollars per share)		$ 18.00
Validation batches		$ 60.9
Minimum
Business Overview And Summary Of Significant Accounting Policies
Accounts Receivable, Standard Credit Term												30 days
Accounts Receivable, Consolidated Average Term of Sales Outstanding												70 days
Inventory estimated life (in months)												36
Minimum \| Building and improvements
Business Overview And Summary Of Significant Accounting Policies
Useful life												15 years
Minimum \| Machinery and laboratory equipment
Business Overview And Summary Of Significant Accounting Policies
Useful life												5 years
Minimum \| Computer hardware and software
Business Overview And Summary Of Significant Accounting Policies
Useful life												3 years
Minimum \| Furniture and office equipment
Business Overview And Summary Of Significant Accounting Policies
Useful life												5 years
Maximum
Business Overview And Summary Of Significant Accounting Policies
Accounts Receivable, Standard Credit Term												120 days
Accounts Receivable, Consolidated Average Term of Sales Outstanding												80 days
Inventory estimated life (in months)												48
Maximum \| Building and improvements
Business Overview And Summary Of Significant Accounting Policies
Useful life												35 years
Maximum \| Machinery and laboratory equipment
Business Overview And Summary Of Significant Accounting Policies
Useful life												15 years
Maximum \| Computer hardware and software
Business Overview And Summary Of Significant Accounting Policies
Useful life												7 years
Maximum \| Furniture and office equipment
Business Overview And Summary Of Significant Accounting Policies
Useful life												10 years
Customer Concentration Risk \| Four Largest Customers \| Accounts Receivable
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales												66.80%	66.90%
Customer Concentration Risk \| Four Largest Customers \| Accounts Receivable \| Minimum
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales												11.70%	11.60%
Customer Concentration Risk \| Four Largest Customers \| Accounts Receivable \| Maximum
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales												22.10%	20.30%
Customer Concentration Risk \| Four Largest Customers \| Sales Revenue, Product Line
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales													56.40%	50.30%
Customer Concentration Risk \| Four Largest Customers \| Sales Revenue, Product Line \| Minimum
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales													10.00%	10.00%
Customer Concentration Risk \| Four Largest Customers \| Sales Revenue, Product Line \| Maximum
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales													16.80%	16.40%
Customer Concentration Risk \| Three Largest Customers \| Sales Revenue, Product Line
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales												47.40%
Customer Concentration Risk \| Three Largest Customers \| Sales Revenue, Product Line \| Minimum
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales												14.70%
Customer Concentration Risk \| Three Largest Customers \| Sales Revenue, Product Line \| Maximum
Business Overview And Summary Of Significant Accounting Policies
Percentage change in product sales												16.70%
Accounting Standards Update 2014-09
Business Overview And Summary Of Significant Accounting Policies
Increase (decrease) in retained earnings														$ 10.8	$ 6.0
Decrease in deferred revenue														17.9	$ 10.4
Accounting Standards Update 2016-02
Business Overview And Summary Of Significant Accounting Policies
Decrease in property, plant and equipment and other assets														472.8
Decrease in facility lease obligation														372.2
Right of use operating assets											$ 172.2			326.1
Prepaid Rent														70.8
Operating Lease, Liability														255.3
Increase (decrease) in retained earnings														(90.3)
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Business Overview And Summary Of Significant Accounting Policies
Total revenues														5.3
Net income														$ 4.8
Pre-Approval Inventory
Business Overview And Summary Of Significant Accounting Policies
Inventories				$ 39.8				$ 60.5				$ 39.8	$ 60.5

Business Overview and Summary of Significant Accounting Policies (Inventories) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Inventory
Raw materials	$ 91.2	$ 41.2
Work-in-process	260.8	180.8
Finished goods	510.3	405.6
Inventory, Net	862.3	627.6
Inventories
Inventory
Inventory, Net	775.7	627.6
Other assets
Inventory
Inventory, Net	$ 86.6	$ 0.0

Business Overview and Summary of Significant Accounting Policies (Receivables and Contract Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Receivables, which are included in "Trade accounts receivable, net"	$ 1,409.3	$ 1,243.2
Contract liabilities, which are included in "Other current liabilities"	$ 3.0	$ 6.8

Business Overview and Summary of Significant Accounting Policies (Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Overview and Summary of Significant Accounting Policies [Abstract]
Net income used for basic and diluted calculation	$ 535.8	$ 578.1	$ (1,068.1)	$ 557.6	$ 889.0	$ 467.6	$ 459.8	$ 587.9	$ 603.4	$ 2,404.3	$ 77.6
Shares used in computing earnings per common share—basic									220.1	223.2	222.7
Weighted-average effect of dilutive securities:
Stock awards									1.9	1.6	1.8
Shares used in computing earnings per common share—diluted									222.0	224.8	224.5
Earnings per common share
Basic (in dollars per share)	$ 2.45	$ 2.64	$ (4.84)	$ 2.52	$ 4.02	$ 2.09	$ 2.05	$ 2.63	$ 2.74	$ 10.77	$ 0.35
Diluted (in dollars per share)	$ 2.42	$ 2.62	$ (4.84)	$ 2.50	$ 4.00	$ 2.08	$ 2.04	$ 2.61	$ 2.72	$ 10.70	$ 0.35
Antidilutive securities excluded from computation of EPS									1.7	3.0	2.8

Acquisitions (Narrative) (Details)					1 Months Ended			3 Months Ended				12 Months Ended
Acquisitions (Narrative) (Details)	Dec. 12, 2020 $ / shares	Jul. 02, 2020 USD ($) $ / shares	Jan. 28, 2020 USD ($) $ / shares	May 25, 2018 USD ($)	Apr. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Nov. 30, 2018 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Apr. 30, 2018 kr / shares	Feb. 28, 2017 USD ($)
Business Acquisition
Change in fair value of contingent consideration												$ 61,200,000	$ 11,600,000	$ 116,500,000
Accelerated cost								$ (36,800,000)		$ 0				0
Weighted average cost of capital												11.50%
Payment to acquire other investments												$ 38,100,000	73,300,000	10,300,000
Net operating losses								318,100,000		102,900,000		318,100,000	102,900,000
Income tax credits								465,100,000		328,100,000		465,100,000	328,100,000
Deferred tax liabilities, inventory								53,500,000		0		53,500,000	0
Acquisition costs not expensed												150,800,000
Acquisition cost adjustment													136,400,000
Acquisition costs								117,600,000		$ 0				$ 0
Amounts issued												160,700,000
Wilson Therapeutics
Business Acquisition
Amounts issued				$ 19,000,000.0
Syntimmune, Inc
Business Acquisition
Amounts issued							$ 800,000,000.0
Upfront payment for acquisition of Syntimmune outstanding shares							400,000,000.0
Total consideration transferred							$ 1,200,000,000.0
HealthCare Royalty Partners \| Royalty-Based Financing Agreement
Business Acquisition
Repayments of debt												5,000,000.0
Carrying value as of December 31, 2020								187,000,000.0				$ 187,000,000.0
HealthCare Royalty Partners \| Royalty-Based Financing Agreement \| Portola
Business Acquisition
Repayments of debt		$ 13,700,000
Maximum potential royalty payments																$ 290,600,000
Portola Pharmaceuticals
Business Acquisition
Payment to acquire other investments					$ 3,600,000	$ 14,500,000
Fair value of equity securities		$ 47,800,000
Acquired IPRD
Business Acquisition
Impairment of indefinite-lived intangible assets									$ 11,000,000.0
Minimum \| Level 3 \| Acquisition-related contingent consideration
Business Acquisition
Fair value inputs, cost of debt			2.10%									2.80%
Weighted average cost of capital												9.00%
Maximum \| Level 3 \| Acquisition-related contingent consideration
Business Acquisition
Fair value inputs, cost of debt			2.30%									3.30%
Achillion
Business Acquisition
Consideration transferred per share (in dollars per share) \| $ / shares			$ 6.30
Upfront payment to shareholders and option holders			$ 926,200,000
Goodwill adjustments									$ 3,100,000
Noncurrent contingent consideration			160,700,000					210,600,000				$ 210,600,000
Contingent consideration, post-combination service period compensation			5,700,000
Change in fair value of contingent consideration												49,900,000
Accelerated cost			(20,000,000.0)									(25,700,000)
Deferred tax liabilities assumed			62,900,000
Deferred tax assets, net			142,400,000
Pre-tax loss since acquisition												66,800,000
Acquisition costs												38,100,000
Achillion \| Acquired IPRD
Business Acquisition
Indefinite intangible assets acquired			918,000,000.0
Deferred tax liabilities assumed			205,300,000
Achillion \| Minimum
Business Acquisition
Estimated milestone payments			0
Achillion \| Maximum
Business Acquisition
Estimated milestone payments			$ 306,300,000
Portola
Business Acquisition
Consideration transferred per share (in dollars per share) \| $ / shares		$ 18.00
Upfront payment to shareholders and option holders		$ 1,380,800,000
Goodwill adjustments								(600,000)
Accelerated cost		(11,100,000)
Deferred tax assets, net		116,600,000
Pre-tax loss since acquisition												80,500,000
Equity compensation replacement awards		41,500,000
Equity interest, fair value		7,200,000
Repayments of debt		196,900,000
Inventory assumed		$ 362,500,000
Discount rate		17.50%
Net operating losses		$ 301,600,000
Income tax credits		41,800,000
Deferred tax assets, long-term debt		42,400,000
Deferred tax assets, other		39,300,000
Deferred tax liabilities, intangible assets		245,100,000
Deferred tax liabilities, inventory		63,400,000
Revenue since acquisition date												78,800,000
Amortization since acquisition date												51,800,000
Intangible asset amortization expense, adjustment												39,800,000	79,500,000
Cost of goods sold adjustment												11,000,000.0	$ 24,400,000
Acquisition costs												77,500,000
Portola \| HealthCare Royalty Partners \| Royalty-Based Financing Agreement
Business Acquisition
Total repayment obligation as of the acquisition date		276,900,000
Carrying value as of December 31, 2020		$ 182,000,000.0
Portola \| ANDEXXA
Business Acquisition
Useful life		3 years
Discount rate		17.50%
Portola \| Acquired IPRD
Business Acquisition
Indefinite intangible assets acquired								$ 15,000,000.0				15,000,000.0
Portola \| Minimum
Business Acquisition
Discount rate		3.30%
Portola \| Maximum
Business Acquisition
Discount rate		7.10%
AstraZeneca
Business Acquisition
Consideration transferred per share (in dollars per share) \| $ / shares	$ 60.00
Acquisition costs												2,000,000.0
Purchased technology
Business Acquisition
Impairment of indefinite-lived intangible assets												$ 2,042,300,000
Purchased technology \| Minimum
Business Acquisition
Finite intangible asset useful life												6 years
Purchased technology \| Maximum
Business Acquisition
Finite intangible asset useful life												16 years
Purchased technology \| Portola
Business Acquisition
Finite intangible assets assumed		$ 1,036,000,000.0
Finite intangible asset useful life		10 years
In Process Research and Development
Business Acquisition
Asset acquisition, share price (dollars per share) \| kr / shares															kr 232
Upfront payment for acquisition of Syntimmune outstanding shares				$ 749,300,000
In Process Research and Development \| Syntimmune, Inc
Business Acquisition
Benefit from previously acquired research and development											$ 4,100,000
Danicopan \| Achillion
Business Acquisition
Contingent consideration per share (dollars per share) \| $ / shares			$ 1.00
ACH-5528, Phase 3 \| Achillion
Business Acquisition
Contingent consideration per share (dollars per share) \| $ / shares			$ 1.00

Acquisitions (Reconciliation of Upfront Payments To Total Purchase Price) (Details) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
	Jul. 02, 2020	Jan. 28, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2018
Business Acquisition
Upfront payment, fair value of equity compensation attributable to the post-combination service period			$ (36.8)	$ 0.0		$ 0.0
Goodwill			5,100.1	$ 5,037.4	$ 5,100.1
Portola Pharmaceuticals
Business Acquisition
Fair value of equity shares held by Alexion at closing	$ 47.8
Achillion
Business Acquisition
Upfront payment to shareholders and option holders		$ 926.2
Upfront payment, fair value of equity compensation attributable to the post-combination service period		(20.0)			(25.7)
Upfront cash paid, net		906.2
Contingent consideration		160.7	210.6		210.6
Contingent consideration, fair value of equity compensation attributable to the post-combination service period		(5.7)
Total consideration		1,061.2
Cash and cash equivalents		68.5
Marketable securities		106.1
Goodwill		37.8
Deferred tax liabilities, net		(62.9)
Other assets and liabilities, net		(6.3)
Total net assets acquired		1,061.2
Deferred tax assets, net		142.4
Achillion \| Acquired IPRD
Business Acquisition
In-process research & development assets (IPR&D)		918.0
Deferred tax liabilities, net		$ (205.3)
Portola
Business Acquisition
Upfront payment to shareholders and option holders	1,380.8
Upfront payment, fair value of equity compensation attributable to the post-combination service period	(11.1)
Upfront cash paid, net	1,369.7
Total consideration	1,621.6
Cash and cash equivalents	288.5
Marketable securities	17.8
Goodwill	24.9
Fair value of replacement equity awards attributable to the pre-combination period	7.2
Total consideration to acquire outstanding equity, net	1,424.7
Total consideration to settle preexisting debt	196.9
Inventory assumed	362.5
Intangible assets	1,051.0
Deferred tax assets, net	116.6
Other assets	41.9
Accounts payable and accrued expenses	(75.6)
Long-term debt, including current portion of $7.7	(182.0)
Other liabilities	(24.0)
Total net assets acquired	1,621.6
Validation batches	60.9
Noncurrent inventory	169.1
Current debt	$ 7.7
Portola \| Acquired IPRD
Business Acquisition
In-process research & development assets (IPR&D)			$ 15.0		$ 15.0

Acquisitions (Pro Forma Financial Information Of Combined Results Of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Combinations [Abstract]
Pro forma revenue	$ 6,118.3	$ 5,107.7
Pro forma net income	$ 519.9	$ 1,813.6

Acquisitions (Acquisition Costs) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Transaction costs	$ 9.9	$ 0.0	$ 0.0
Integration costs	13.0	0.0	0.0
Fair value of equity compensation attributable to the post-combination service period	36.8	0.0	0.0
Employee separation costs	57.9	0.0	0.0
Acquisition costs	$ 117.6	$ 0.0	$ 0.0

Acquisitions (Summary of Total Consideration) (Details) - In Process Research and Development $ in Millions	May 25, 2018 USD ($)
Acquired Finite-Lived Intangible Assets
Cash paid for acquisition of Wilson Therapeutics outstanding shares	$ 749.3
Transaction costs	15.1
Total consideration	764.4
Cash	45.1
In-process research & development	803.7
Employee related liabilities	(71.4)
Other assets and liabilities	$ (13.0)

Acquisitions (Syntimmune) (Details) - Syntimmune, Inc $ in Millions	1 Months Ended
	Nov. 30, 2018 USD ($)
Consideration
Upfront payment for acquisition of Syntimmune outstanding shares	$ 400.0
Cash acquired	4.2
Working capital adjustment	2.3
Transaction costs	0.9
Total consideration	407.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash	4.2
In-process research & development	375.2
Deferred tax assets	25.1
Other assets and liabilities	2.9
Total net assets acquired	$ 407.4

Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment
Land	$ 9.6	$ 9.6
Buildings and improvements	216.7	208.7
Machinery and laboratory equipment	134.1	126.0
Computer hardware and software	171.9	155.1
Furniture and office equipment	24.9	23.4
Construction-in-progress	828.7	734.2
Financing lease right of use assets	127.2	127.2
Property, Plant and Equipment, Gross	1,513.1	1,384.2
Less: Accumulated depreciation and amortization	(274.3)	(220.9)
Property, Plant and Equipment, Net	1,238.8	1,163.3
Depreciation and amortization of property, plant and equipment	329.4	376.8	$ 405.3
Computer software costs	53.1	53.4
Capitalized Computer Software, Accumulated Amortization	87.7	72.9
Computer software, depreciation and amortization expense	16.4	15.3	17.4
Property, Plant, and Equipment
Property, Plant and Equipment
Depreciation and amortization of property, plant and equipment	$ 56.3	$ 56.8	$ 77.9

Intangible Assets and Goodwill (Schedule of Intangible Assets and Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Intangible Assets
Intangible Assets, Cost		$ 6,736.4	$ 4,778.4
Intangible Assets, Accumulated Amortization		(3,734.0)	(1,434.1)
Intangible assets, net		3,002.4	3,344.3
Goodwill, Cost		5,103.0	5,040.3
Goodwill, Accumulated Amortization		(2.9)	(2.9)
Goodwill		5,100.1	5,037.4
Licensing Rights
Intangible Assets
Cost		57.0	57.0
Accumulated Amortization		(38.5)	(34.7)
Net		$ 18.5	22.3
Patents
Intangible Assets
Estimated Life (years)		7 years
Cost		$ 10.5	10.5
Accumulated Amortization		(10.5)	(10.5)
Net		0.0	0.0
Purchased technology
Intangible Assets
Cost		5,746.5	4,710.5
Accumulated Amortization		(3,684.7)	(1,388.7)
Net		2,061.8	3,321.8
Impairment of indefinite-lived intangible assets		$ 2,042.3
Other Intangibles
Intangible Assets
Estimated Life (years)		5 years
Cost		$ 0.4	0.4
Accumulated Amortization		(0.3)	(0.2)
Net		$ 0.1	0.2
Minimum \| Licensing Rights
Intangible Assets
Estimated Life (years)		3 years
Minimum \| Purchased technology
Intangible Assets
Estimated Life (years)		6 years
Maximum \| Licensing Rights
Intangible Assets
Estimated Life (years)		8 years
Maximum \| Purchased technology
Intangible Assets
Estimated Life (years)		16 years
Acquired IPRD
Intangible Assets
Indefinite-Lived Intangible Assets, Gross (Excluding Goodwill)		$ 922.0	0.0
Indefinite-lived Intangible Assets (Excluding Goodwill)		$ 922.0	$ 0.0
Impairment of indefinite-lived intangible assets	$ 11.0

Intangible Assets and Goodwill (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 02, 2020	Jan. 28, 2020
Goodwill and Intangibles Disclosure
Goodwill		$ 5,100.1	$ 5,037.4
Impairment of intangible assets		2,053.3	0.0	$ 0.0
Capitalized regulatory approval and commercial milestones			18.0
Amortization of Intangible Assets		257.6	315.0	$ 321.1
2021		216.0
2022		216.0
2023		216.0
2024		216.0
2025		216.0
Achillion
Goodwill and Intangibles Disclosure
Goodwill						$ 37.8
Portola
Goodwill and Intangibles Disclosure
Goodwill					$ 24.9
Acquired IPRD
Goodwill and Intangibles Disclosure
Impairment of intangible assets		11.0
Impairment of indefinite-lived intangible assets	$ 11.0
Acquired IPRD \| Achillion
Goodwill and Intangibles Disclosure
Indefinite intangible assets acquired						$ 918.0
Acquired IPRD \| Portola
Goodwill and Intangibles Disclosure
Indefinite intangible assets acquired		15.0
Purchased technology
Goodwill and Intangibles Disclosure
Impairment of indefinite-lived intangible assets		2,042.3
Finite-Lived Intangible Assets, Net		2,061.8	$ 3,321.8
Purchased technology \| Portola
Goodwill and Intangibles Disclosure
Finite intangible assets assumed					$ 1,036.0
KANUMA
Goodwill and Intangibles Disclosure
Intangible Assets, Impairment, Weighted Average Cost Of Capital	10.00%
Finite-Lived Intangible Assets, Net	$ 820.0	$ 782.7

Intangible Assets and Goodwill (Schedule of Changes in the Carrying Amount of Goodwill) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Goodwill [Roll Forward]
Balance as of December 31, 2019	$ 5,037.4
Goodwill resulting from the acquisitions of Achillion and Portola	62.7
Balance as of December 31, 2020	$ 5,100.1

Marketable Securities (Realized Gains and Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Proceeds from maturities and sales	$ 1,042.5	$ 2,832.8	$ 10,196.8
Realized gains	0.0	0.0	1.1
Realized losses	$ 0.0	$ 0.0	$ 0.4

Marketable Securities (Summary of Avaiable-for-sale Securities Held) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale
Amortized Cost		$ 369.0
Gross Unrealized Holding Gains		0.0
Gross Unrealized Holding Losses		0.0
Fair Value	$ 0.0	369.0
Commercial paper
Debt Securities, Available-for-sale
Amortized Cost		246.9
Gross Unrealized Holding Gains		0.0
Gross Unrealized Holding Losses		0.0
Fair Value		246.9
Corporate bonds
Debt Securities, Available-for-sale
Amortized Cost		24.3
Gross Unrealized Holding Gains		0.0
Gross Unrealized Holding Losses		0.0
Fair Value		24.3
U.S.
Debt Securities, Available-for-sale
Amortized Cost		70.4
Gross Unrealized Holding Gains		0.0
Gross Unrealized Holding Losses		0.0
Fair Value		70.4
Bank certificates of deposit
Debt Securities, Available-for-sale
Amortized Cost		27.4
Gross Unrealized Holding Gains		0.0
Gross Unrealized Holding Losses		0.0
Fair Value		$ 27.4

Marketable Securities (Available-for-sale Securities by Classification in Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale
Fair Value	$ 0.0	$ 369.0
Cash and Cash Equivalents [Member]
Debt Securities, Available-for-sale
Fair Value	0.0	328.1
Marketable securities
Debt Securities, Available-for-sale
Fair Value	$ 0.0	$ 40.9

Marketable Securities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale
Aggregate fair value of available-for-sale debt securities in an unrealized loss position		$ 21.5
Debt Securities, Trading, and Equity Securities, FV-NI	$ 34.9	$ 23.1

Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Not Designated as Hedging Instrument
Derivative
Foreign exchange forward contracts durations (months)	6 months
Gain in other income and expense	$ (3.6)	$ (0.4)	$ 23.0
Foreign exchange forward contracts \| Designated as Hedging Instrument
Derivative
Foreign exchange forward contracts durations (months)	23 months
Notional Amount	$ 1,174.7
Foreign exchange forward contracts \| Designated as Hedging Instrument \| Sales
Derivative
Estimated amount to be reclassified from other comprehenisve income in next year	(44.2)
Foreign exchange forward contracts \| Not Designated as Hedging Instrument
Derivative
Notional Amount	$ 2,070.1
Foreign Exchange Forward, Open Expense \| Designated as Hedging Instrument
Derivative
Foreign exchange forward contracts durations (months)	60 months
Notional Amount	$ 8.7
Interest rate swap contracts \| Designated as Hedging Instrument
Derivative
Estimated amount to be reclassified from other comprehenisve income in next year	$ (45.9)

Derivative Instruments and Hedging Activities (Schedule of Interest Rate Derivatives) (Details) - Designated as Hedging Instrument $ in Millions	Dec. 31, 2020 USD ($)
Interest Rate Swap Two
Derivative
Notional Amount	$ 450.0
Interest Rate Swap Two \| Minimum
Derivative
Fixed Interest Rate or Rate Range	2.60%
Interest Rate Swap Two \| Maximum
Derivative
Fixed Interest Rate or Rate Range	2.79%
Interest Rate Swap Four
Derivative
Notional Amount	$ 1,300.0
Interest Rate Swap Four \| Minimum
Derivative
Fixed Interest Rate or Rate Range	2.37%
Interest Rate Swap Four \| Maximum
Derivative
Fixed Interest Rate or Rate Range	2.83%

Derivative Instruments and Hedging Activities (Schedule of Cash Flow Hedges in AOCI) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative
Total revenues	$ 1,591.8	$ 1,588.7	$ 1,444.6	$ 1,444.8	$ 1,384.3	$ 1,263.1	$ 1,203.3	$ 1,140.4	$ 6,069.9	$ 4,991.1	$ 4,131.2
Interest Expense									104.7	77.8	98.2
Net Product Sales
Derivative
Total revenues									6,069.1	4,990.0	4,130.1
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest \| Reclassification out of Accumulated Other Comprehensive Income \| Foreign exchange forward contracts
Derivative
Total revenues									4.7	36.8	(1.8)
Interest Expense									0.0	0.0	0.0
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest \| Reclassification out of Accumulated Other Comprehensive Income \| Interest rate swap contracts
Derivative
Total revenues									0.0	0.0	0.0
Interest Expense									$ (37.5)	$ 13.3	$ 13.6

Derivative Instruments and Hedging Activities (Schedule Of Other Comprehensive Income And Earnings From Foreign Exchange Contracts) (Details) - Cash Flow Hedging - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Foreign exchange forward contracts
Derivative Instruments and Hedging Activities Disclosures
(Loss) gain recognized in AOCI, net of tax	$ (36.4)	$ 27.9	$ 37.7
Foreign exchange forward contracts \| Sales
Derivative Instruments and Hedging Activities Disclosures
Gain (loss) reclassified from AOCI to net product sales, net of tax	3.6	28.4	(1.4)
Interest rate swap contracts
Derivative Instruments and Hedging Activities Disclosures
(Loss) gain recognized in AOCI, net of tax	(52.3)	(39.0)	(4.8)
Interest rate swap contracts \| Interest Expense
Derivative Instruments and Hedging Activities Disclosures
Gain (loss) reclassified from AOCI to net product sales, net of tax	$ (29.1)	$ 10.2	$ 10.8

Derivative Instruments and Hedging Activities (Schedule Of Fair Value Of Outstanding Derivatives) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value
Asset Derivatives	$ 26.1	$ 30.5
Liability Derivatives	172.6	89.1
Foreign exchange forward contracts
Derivatives, Fair Value
Asset Derivatives	26.1	30.5
Liability Derivatives	172.6	89.1
Foreign exchange forward contracts \| Prepaid expenses and other current assets \| Designated as Hedging Instrument
Derivatives, Fair Value
Asset Derivatives	0.0	12.7
Foreign exchange forward contracts \| Other current liabilities \| Designated as Hedging Instrument
Derivatives, Fair Value
Liability Derivatives	44.3	6.2
Foreign exchange forward contracts \| Other assets \| Designated as Hedging Instrument
Derivatives, Fair Value
Asset Derivatives	0.0	0.6
Foreign exchange forward contracts \| Other liabilities \| Designated as Hedging Instrument
Derivatives, Fair Value
Liability Derivatives	1.2	1.1
Foreign exchange forward contracts \| Foreign exchange forward contracts \| Prepaid expenses and other current assets \| Not Designated as Hedging Instrument
Derivatives, Fair Value
Asset Derivatives	26.1	17.2
Foreign exchange forward contracts \| Foreign exchange forward contracts \| Other current liabilities \| Not Designated as Hedging Instrument
Derivatives, Fair Value
Liability Derivatives	35.8	20.4
Interest rate swap contracts \| Prepaid expenses and other current assets \| Designated as Hedging Instrument
Derivatives, Fair Value
Interest rate contracts	0.0	0.0
Interest rate swap contracts \| Other current liabilities \| Designated as Hedging Instrument
Derivatives, Fair Value
Liability Derivatives	45.9	19.5
Interest rate swap contracts \| Other assets \| Designated as Hedging Instrument
Derivatives, Fair Value
Interest rate contracts	0.0	0.0
Interest rate swap contracts \| Other liabilities \| Designated as Hedging Instrument
Derivatives, Fair Value
Liability Derivatives	$ 45.4	$ 41.9

Derivative Instruments and Hedging Activities (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets/Liabilities	$ 26.1	$ 30.5
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets/Liabilities	(172.6)	(89.1)
Foreign exchange forward contracts
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets/Liabilities	26.1	30.5
Gross Amounts Offset in the Consolidated Balance Sheet	0.0	0.0
Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheet	26.1	30.5
Derivative Financial Instruments	(26.1)	(21.4)
Cash Collateral Received (Pledged)	0.0	0.0
Net Amount	0.0	9.1
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets/Liabilities	(172.6)	(89.1)
Gross Amounts Offset in the Consolidated Balance Sheet	0.0	0.0
Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheet	(172.6)	(89.1)
Derivative Financial Instruments	26.1	21.4
Cash Collateral Received (Pledged)	0.0	0.0
Net Amount	$ (146.5)	$ (67.7)

Other Investments (Details) - USD ($) $ in Millions				1 Months Ended								3 Months Ended			12 Months Ended
Other Investments (Details) - USD ($) $ in Millions	Jul. 17, 2020	Jul. 02, 2020	Dec. 09, 2019	Dec. 31, 2020	Apr. 30, 2020	Mar. 31, 2020	Oct. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Jan. 31, 2019	Oct. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2014
Payment to acquire other investments															$ 38.1	$ 73.3	$ 10.3
Unrealized Gain (Loss) on Investments															(3.0)	26.9	40.2
Other income and (expense)															(3.3)	35.9	5.5
Gain (Loss) on Disposition of Assets															14.8	0.0	0.0
Moderna LLC
Payment to acquire other investments																		$ 37.5
Unrealized Gain (Loss) on Investments													$ (56.4)	$ 100.8
Proceeds from sale of investment			$ 114.7
Realized gain from sale of investment			$ 77.2													32.8
Dicerna
Unrealized Gain (Loss) on Investments															0.0	9.5	$ (1.4)
Payments to Acquire Equity Method Investments											$ 10.3
Fair value of equity securities				$ 18.4								$ 18.4			18.4	18.4
Caelum Biosciences
Payment to acquire other investments										$ 41.0					41.0	41.0
Option To Acquire Remaining Equity, Amount										$ 16.1
Other income and (expense)												32.0
Caelum Biosciences, Option
Payment to acquire other investments															15.0	64.0
Equity Method Investment, Other than Temporary Impairment				49.0
Zealand
Unrealized Gain (Loss) on Investments															(1.9)	14.7
Payments to Acquire Equity Method Investments									$ 13.8
Fair value of equity securities				29.1								28.5			29.1	28.5
Eidos
Unrealized Gain (Loss) on Investments															45.4	7.9
Payments to Acquire Equity Method Investments								$ 19.9
Fair value of equity securities				73.2								27.8			73.2	27.8
Stealth
Unrealized Gain (Loss) on Investments															(2.4)	(5.2)
Payments to Acquire Equity Method Investments							$ 9.6
Fair value of equity securities				2.0								$ 4.4			2.0	4.4
Portola Pharmaceuticals
Payment to acquire other investments					$ 3.6	$ 14.5
Realized gain from sale of investment		$ 29.7
Fair value of equity securities		$ 47.8
Inozyme
Unrealized Gain (Loss) on Investments															5.7
Fair value of equity securities				$ 20.5											20.5
Gain (Loss) on Disposition of Assets	$ 14.8
Collaborative Arrangement \| Caelum Biosciences
Additional upfront funding accrued																20.0
Research and Development Expense															$ 6.0	3.1
Collaborative Agreement, Amendment \| Caelum Biosciences
Research and Development Expense																$ 4.1

Accounts Payable and Accrued Expenses (Schedule of Accrued Expenses) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities [Abstract]
Accounts payable	$ 118.6	$ 74.0
Royalties	27.6	20.1
Payroll and employee benefits	242.3	187.5
Taxes payable	150.9	103.9
Rebates payable	333.3	250.1
Clinical	97.0	67.3
Manufacturing	58.2	72.8
Accrued severance and restructuring costs	31.7	12.8
Other	143.7	178.2
Accounts Payable and Accrued Liabilities, Current	$ 1,203.3	$ 966.7

Debt (Details) - USD ($)			1 Months Ended	3 Months Ended		12 Months Ended
Debt (Details) - USD ($)	Jul. 02, 2020	Jun. 07, 2018	Feb. 28, 2017	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2018
Debt Instrument
Amortization of Financing Costs					$ 4,700,000		$ 5,000,000.0	$ 8,000,000.0
Debt Issuance Costs, Net					11,100,000	$ 11,100,000	15,800,000
Current portion of long-term debt					142,400,000	142,400,000	126,700,000
Long-term debt, less current portion					$ 2,419,600,000	$ 2,419,600,000	2,375,000,000.0
Portola
Debt Instrument
Deferred tax assets, long-term debt	$ 42,400,000
Less: payments made	(196,900,000)
Credit Agreement
Debt Instrument
Payments of Financing Costs								$ 53,100,000
Royalty-Based Financing Agreement \| HealthCare Royalty Partners
Debt Instrument
Debt Instrument, Interest Rate at Period End					11.50%	11.50%
Carrying value as of December 31, 2020					$ 187,000,000.0	$ 187,000,000.0
Interest Expense, Debt						10,000,000.0
Less: payments made						(5,000,000.0)
Current portion of long-term debt					15,500,000	15,500,000
Long-term debt, less current portion					$ 171,500,000	$ 171,500,000
Royalty-Based Financing Agreement \| HealthCare Royalty Partners \| Forecast
Debt Instrument
Less: payments made				$ (3,000,000.0)
Royalty-Based Financing Agreement \| HealthCare Royalty Partners \| Portola
Debt Instrument
Carrying value as of December 31, 2020	182,000,000.0
Total repayment obligation as of the acquisition date	276,900,000
Debt Instrument, Unamortized Discount	94,900,000
Royalty-Based Financing Agreement \| HealthCare Royalty Partners \| Portola
Debt Instrument
Royalty Agreement, Closing Day Payment			$ 50,000,000.0
Royalty Agreement, Milestone Payment Based On Regulatory Approval									$ 100,000,000.0
Royalty Agreement, Maximum Potential Royalty Payments As A Percentage Of Funding Received			195.00%
Maximum potential royalty payments			$ 290,600,000
Less: payments made	$ (13,700,000)
Line of Credit \| Credit Agreement
Debt Instrument
Debt Instrument, Interest Rate at Period End					1.40%	1.40%
Minimum \| Royalty-Based Financing Agreement \| HealthCare Royalty Partners \| Portola
Debt Instrument
Royalty Agreement, Tiered Royalty, Percent			4.20%
Maximum \| Royalty-Based Financing Agreement \| HealthCare Royalty Partners \| Portola
Debt Instrument
Royalty Agreement, Tiered Royalty, Percent			8.50%
Base Rate \| Minimum \| Line of Credit \| Credit Agreement
Debt Instrument
Debt instrument, basis spread on varaible rate		0.25%
Base Rate \| Maximum \| Line of Credit \| Credit Agreement
Debt Instrument
Debt instrument, basis spread on varaible rate		1.00%
Eurodollar \| Minimum \| Line of Credit \| Credit Agreement
Debt Instrument
Debt instrument, basis spread on varaible rate		1.25%
Eurodollar \| Maximum \| Line of Credit \| Credit Agreement
Debt Instrument
Debt instrument, basis spread on varaible rate		2.00%
Revolving Credit Facility \| Credit Agreement
Debt Instrument
Line of credit facility, maximum borrowing capacity		$ 1,000,000,000.0
Debt Instrument, Covenant Compliance, Net Debt To EBITDA		3.50
Debt Instrument, Covenant Compliance, EBITDA To Cash Interest Expense, Minimum		3.50
Letters of credit, amount outstanding					$ 1,000,000.0	$ 1,000,000.0
Senior Secured Term Loan \| Line of Credit \| Credit Agreement
Debt Instrument
Debt instrument, principal amount		$ 2,612,500,000
Debt Instrument, Quarterly Payment, Percentage of Total Borrowings		5.00%
Principal payments						130,600,000	98,000,000.0
Carrying value as of December 31, 2020					$ 2,383,900,000	$ 2,383,900,000	$ 2,514,500,000

Debt (Schedule of Debt) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
Debt (Schedule of Debt) (Details) - USD ($) $ in Millions	Jul. 02, 2020	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument
Less: interest to be accreted in future periods		$ (84.9)
Portola
Debt Instrument
Less: payments made	$ (196.9)
Royalty-Based Financing Agreement \| HealthCare Royalty Partners
Debt Instrument
Less: payments made			$ (5.0)
Carrying value as of December 31, 2020			$ 187.0
Royalty-Based Financing Agreement \| HealthCare Royalty Partners \| Portola
Debt Instrument
Total repayment obligation as of the acquisition date	276.9
Carrying value as of December 31, 2020	$ 182.0

Debt - Schedule of Maturities of Long-term Debt (Details) $ in Millions	Dec. 31, 2020 USD ($)
Debt Disclosure [Abstract]
2021	$ 146.1
2022	158.4
2023	2,167.7
2024	63.6
2025	76.5
Thereafter	$ 43.5

Leases - Lease Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Right of use operating assets	$ 223.1	$ 204.0
Financing lease right of use assets	105.4	116.3
Finance Lease, Liability, Current	5.6	5.2
Operating Lease, Liability, Current	28.1	18.8
Finance Lease, Liability, Noncurrent	67.3	72.9
Noncurrent operating lease liabilities	$ 177.1	$ 164.1
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent

Leases - Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
Leases - Lease Cost (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Financing Lease Cost	$ 14.5	$ 14.8
Amortization of ROU Assets	10.9	10.9
Interest on Lease Liabilities	3.6	3.9
Operating Lease Cost	38.1	34.3
Variable Lease Cost	8.7	11.8
Total Lease Cost	$ 61.3	$ 60.9

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Leases - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating Leased Assets
Lease cost	$ 61.3	$ 60.9
Inventory
Operating Leased Assets
Lease cost	$ 11.9	$ 15.6

Leases - Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description
Cash Paid For Amounts Included In Measurement of Liabilities		$ 39.4	$ 32.3
Operating Cash Flows From Financing Leases		3.6	3.9
Operating Cash Flows From Operating Leases		30.7	23.5
Financing Cash Flows From Financing Leases		5.1	4.9
ROU Assets Obtained In Exchange For New Financing Liabilities		0.0	0.0
ROU Asset Obtained In Exchange for New Operating Liabilities		31.6	27.5	$ 0.0
Financing lease right of use assets		105.4	116.3
Right-of-Use Asset Obtained in Exchange for Finance Lease Rent Prepayment	$ 44.2
Right of use operating assets		$ 223.1	$ 204.0
Right-of-Use Asset Obtained in Exchange for Operating Lease, Rent Prepayments	26.6
Accounting Standards Update 2016-02
Lessee, Lease, Description
Financing lease right of use assets	83.1
Right of use operating assets	$ 172.2			$ 326.1

Leases - Lease Maturity (Details) $ in Millions	Dec. 31, 2020 USD ($)
Financing
2021	$ 9.0
2022	9.2
2023	9.2
2024	9.4
2025	9.6
Thereafter	45.0
Operating
2021	34.4
2022	32.0
2023	25.2
2024	22.5
2025	20.7
Thereafter	103.1
Total
2021	43.4
2022	41.2
2023	34.4
2024	31.9
2025	30.3
Thereafter	$ 148.1

Leases - Lease Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Finance Lease, Weighted Average Remaining Lease Term	9 years 8 months 1 day	10 years 8 months 1 day
Finance Lease, Weighted Average Discount Rate, Percent	4.90%	4.90%
Finance Lease, Liability, Payments, Due	$ 91.4	$ 100.2
Finance Lease, Liability, Undiscounted Excess Amount	18.5	22.1
Finance Lease, Liability	$ 72.9	$ 78.1
Operating Lease, Weighted Average Remaining Lease Term	8 years 10 months 13 days	10 years 2 months 1 day
Operating Lease, Weighted Average Discount Rate, Percent	3.40%	4.10%
Lessee, Operating Lease, Liability, Payments, Due	$ 237.9	$ 223.6
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	32.7	40.7
Operating Lease, Liability	$ 205.2	$ 182.9
Lease, Weighted Average Remaining Lease Term	9 years 29 days	10 years 3 months 25 days
Lease, Weighted Average Discount Rate	3.80%	4.30%
Lessee, Lease Liability, Payments, Due	$ 329.3	$ 323.8
Lessee, Lease Liability, Undiscounted Excess Amount	51.2	62.8
Lessee, Lease Liability	$ 278.1	$ 261.0

Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions		1 Months Ended										3 Months Ended					12 Months Ended
	Jul. 02, 2020	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2019	Sep. 30, 2019	Apr. 30, 2019	Mar. 31, 2019	Jan. 31, 2019	Nov. 30, 2018	Oct. 31, 2018	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 04, 2021
Commitments and Contingencies
Research and Development Expense (Excluding Acquired in Process Cost)																	$ 1,002.9	$ 886.0	$ 730.4
Amounts issued																	160.7
Collaboration Agreement, Milestone Payments To Be Made Next Twelve Months																	71.1
SEC
Commitments and Contingencies
Litigation Settlement, Amount Awarded to Other Party	$ 21.5
DOJ And OIG
Commitments and Contingencies
Loss Contingency Accrual, Payments						$ 13.1
Canadian Patented Medicine Prices Review Board
Commitments and Contingencies
Loss Contingency, Estimate of Possible Loss		$ 49.2										$ 49.2					49.2
Canadian Patented Medicine Prices Review Board \| Subsequent Event
Commitments and Contingencies
Escrow Deposit																				$ 70.7
Lonza Group AG
Commitments and Contingencies
Remaining total commitments with Lonza		1,137.8										1,137.8					1,137.8
Unrecorded Unconditional Purchase Obligation, Undiscounted Fixed Payment Amount		100.5										100.5					100.5
Other Third Party Manufacturers
Commitments and Contingencies
Remaining total commitments with Lonza		175.6										175.6					175.6
Collaborative Arrangement \| Caelum Biosciences
Commitments and Contingencies
Collaboration Agreement, Upfront Payment								$ 30.0
Collaboration Agreement, Potential Future Payments, Milestone Achievement								30.0
Derivative Liability			$ 24.0				$ 27.1						$ 24.0		$ 27.1			24.0
Additional upfront funding accrued																		20.0
Additional equity interest funding			$ 60.0
Collaboration Agreement, Potential Future Payments, Acquisition Option Exercise								500.0
Collaboration Agreement, Milestone Payment																	30.0
Research and Development Expense																	6.0	$ 3.1
Zealand Pharma \| Zealand
Commitments and Contingencies
Collaboration Agreement, Potential Future Payments, Milestone Achievement																	610.0
Payments To Acquire Licenses And Equity Investment							40.0
Prepaid Research And Development Expense							5.0								5.0
Research and Development Expense															$ 21.2
Collaboration Agreement, Potential Future Payments, Additional Milestone Achievement																	115.0
Collaboration Agreement, Potential Future Payments, Option Fee																	15.0
Affibody AB \| Affibody
Commitments and Contingencies
Payments To Acquire Licenses And Equity Investment						$ 25.0
Affibody AB \| Eidos
Commitments and Contingencies
Collaboration Agreement, Potential Future Payments, Milestone Achievement																	30.0
Payments To Acquire Licenses And Equity Investment					$ 50.0
Research and Development Expense														$ 30.1
Dicerna Pharmaceutical Collaboration Agreement \| Dicerna
Commitments and Contingencies
Payments To Acquire Licenses And Equity Investment										$ 37.0
Research and Development Expense													20.0			$ 26.7
Research and Development Arrangement, Potential Payment, Maximum		604.1										604.1					604.1
License Agreement 1 \| Halozyme Therapeutics, Inc
Commitments and Contingencies
Research and Development Arrangement, Potential Payment, Maximum		155.0										155.0					155.0
Research and Development Expense (Excluding Acquired in Process Cost)											$ 40.0
Research and Development Agreement, Option Fee		8.0										8.0					8.0
Research and Development Arrangement, Potential Contingent Payment, Maximum		160.0										160.0					160.0
Collaboration and License Agreement
Commitments and Contingencies
Collaboration Agreement, Potential Future Payments, Milestone Achievement																	$ 114.0
Caelum Biosciences \| Collaborative Arrangement
Commitments and Contingencies
Equity Method Investment, Aggregate Cost								$ 57.1
Caelum Biosciences, Option
Commitments and Contingencies
Equity Method Investment, Other than Temporary Impairment		$ 49.0
Zealand
Commitments and Contingencies
Payments to Acquire Equity Method Investments							$ 13.8
Eidos
Commitments and Contingencies
Payments to Acquire Equity Method Investments					$ 19.9
Stealth
Commitments and Contingencies
Payments To Acquire Licenses And Equity Investment				$ 30.0
Payments to Acquire Equity Method Investments				$ 9.6
Stealth \| Option Agreement
Commitments and Contingencies
Research and Development Expense													$ 20.4
Dicerna
Commitments and Contingencies
Payments to Acquire Equity Method Investments										$ 10.3
Syntimmune, Inc
Commitments and Contingencies
Amounts issued									$ 800.0
Syntimmune, Inc \| Subcutaneous Formulation
Commitments and Contingencies
Amounts issued									$ 130.0
Astellas Pharam
Commitments and Contingencies
Amounts issued												$ 71.5

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency
Current Foreign Tax Expense (Benefit)				$ 245.9	$ 158.2	$ 74.7
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount				$ 240.6	$ 196.1	$ 54.2
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent	3.10%			5.30%	0.10%	1.60%
Foreign Earnings Repatriated				$ 201.5	$ 187.6	$ 206.1
Repatriation of foreign earnings, amount				$ 148.7	$ 269.5	$ 108.7
Foreign-derived intangible income				26.10%	12.40%	44.80%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Contingent Consideration, Percent				1.50%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Contingent Consideration, Amount				$ 8.5
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Gain On Equity Investment, Percent				1.10%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Gain On Equity Investment, Amount				$ 6.2
Deferred Income Tax Expense (Benefit)				$ (283.4)	$ (455.5)	$ 32.9
Income tax rate, intangible asset impairment				19.20%
Income tax (benefit) expense				$ (34.4)	(225.5)	164.6
Tax Adjustments, Settlements, And Unusual Provisions, Net	$ 17.7
Tax Cuts and Jobs Act of 2017, income tax benefit, foreign tax credits						$ 67.7
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Provisional Income Tax Benefit, Foreign, Percent						28.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount						$ 15.8
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other Share-based Payment Arrangement, Percent						6.50%
Tax Cuts and Jobs Act of 2017, transition tax, Income expense							$ 177.9
Tax Cuts and Jobs Act of 2017, transition tax, estimated tax credits							28.0
Tax Cut and Jobs Act of 2017, global intangible low-taxed income minimum tax, income tax expense, deferred tax expense						$ 67.7	236.9
Tax Cuts and Jobs Act of 2017, estimated deferred tax liabilities, foreign						11.1	533.4
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Transition Tax on Accumulated Foreign Earnings, Amount				(1,194.3)
Change in unrecognized tax benefits				$ 21.4	4.6	35.4
Statute of limitations, minimum (years)				3
Statute of limitations, maximum (years)				6
Tax Adjustments, Settlements, and Unusual Provisions				$ 73.8
Income Tax Benefit, Foreign-Derived Intangible Income					$ 17.0
Effective Income Tax Rate Reconciliation, Deduction, Percent					0.80%
State and Local Jurisdiction
Income Tax Contingency
Current Foreign Tax Expense (Benefit)				270.8	$ 193.2	$ 58.1
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)							2.9
Tax Cuts and Jobs Act of 2017, deferred tax liability, estimated increase in income tax payable							2.2
Tax Cuts and Jobs Act of 2017, deferred tax asset, estimated increase in deferred taxes							$ 0.7
Net operating loss carryforwards	108.1			108.1
Operating Loss Carryforwards, Not Subject To Expiration	1.9			1.9
Income tax credit carryforwards	83.5			83.5
Tax credit carryforwards, subject to expiration	51.6			51.6
Tax credit carryforwards, not subject to expiration	31.9			31.9
Federal
Income Tax Contingency
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount	56.1
Net operating loss carryforwards	210.4			210.4
Operating Loss Carryforwards, Not Subject To Expiration	112.8			112.8
Income tax credit carryforwards	417.0			417.0
In Process Research and Development \| Wilson Therapeutics
Income Tax Contingency
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount						69.70%
In Process Research and Development \| Wilson Therapeutics And Syntimmune
Income Tax Contingency
Income tax (benefit) expense						$ 248.4
In Process Research and Development \| Syntimmune, Inc
Income Tax Contingency
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount						32.90%
Purchased technology
Income Tax Contingency
Impairment of indefinite-lived intangible assets				2,042.3
Intangible Asset Impairment
Income Tax Contingency
Deferred Income Tax Expense (Benefit)		$ (377.3)
Intellectual Property Election \| Wilson Therapeutics
Income Tax Contingency
Deferred Income Tax Expense (Benefit)			$ (95.7)		(95.7)
Valuation Allowance Release
Income Tax Contingency
Deferred Income Tax Expense (Benefit)					(30.3)
Valuation Allowance Release \| Wilson Therapeutics
Income Tax Contingency
Deferred Income Tax Expense (Benefit)			$ (30.3)
Wilson Therapeutics
Income Tax Contingency
Income tax (benefit) expense					10.2
Subsidiaries
Income Tax Contingency
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount					$ 1,839.3
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent					17.50%
Subsidiaries \| Intellectual Property Election
Income Tax Contingency
Deferred Income Tax Expense (Benefit)					$ (2,221.5)
Connecticut \| State and Local Jurisdiction
Income Tax Contingency
Net operating loss carryforwards	75.7			75.7
Income tax credit carryforwards	$ 53.7			$ 53.7

Income Taxes (Schedule of Income Tax Provision (Benefit) on Income Before Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S.	$ (1,098.5)	$ 2.0	$ (451.4)
Non-U.S.	1,667.5	2,176.8	693.6
Income before income taxes	$ 569.0	$ 2,178.8	$ 242.2

Income Taxes (Schedule of Components of Income Tax Provision (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Domestic
Current	$ 3.1	$ 71.8	$ 57.0
Deferred	(382.1)	1,731.0	49.5
Total Domestic	(379.0)	1,802.8	106.5
Foreign
Current	245.9	158.2	74.7
Deferred	98.7	(2,186.5)	(16.6)
Total Foreign	344.6	(2,028.3)	58.1
Total
Current	249.0	230.0	131.7
Deferred	(283.4)	(455.5)	32.9
Income Tax Expense (Benefit)	$ (34.4)	$ (225.5)	$ 164.6

Income Taxes (Reconciliation of the Statutory U.S. Federal Income Tax Rate to Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. federal statutory tax rate	21.00%	21.00%	21.00%
Benefit of foreign earnings	(15.50%)	(12.60%)	(71.20%)
Tax credits	(7.30%)	(0.70%)	(17.00%)
Tax reserves	(0.60%)	(0.10%)	12.10%
Acquired in-process research & development	0.00%	0.00%	102.60%
Intra-entity asset transfer of intellectual property	0.40%	(17.50%)	0.00%
Foreign-derived intangible income	(10.00%)	(1.60%)	(4.50%)
U.S. state taxes	(1.60%)	0.70%	14.20%
IRC 162(m) executive compensation	4.10%	0.20%	2.20%
Other permanent differences	3.50%	0.30%	8.60%
Effective Income Tax Rate	(6.00%)	(10.30%)	68.00%

Income Taxes (Schedule of Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating losses	$ 318.1	$ 102.9
Income tax credits	465.1	328.1
Stock compensation	58.6	57.1
Accruals and allowances	138.8	65.2
Unrealized losses	25.4	18.8
Research and development expenses	1.9	3.5
Accrued royalties	1.2	0.8
ROU leases	45.8	46.2
Intangible assets	1,892.0	1,967.3
Gross deferred tax assets	2,946.9	2,589.9
Valuation allowance	(276.0)	(72.6)	$ (19.6)	$ (3.4)
Total deferred tax assets	2,670.9	2,517.3
Deferred tax liabilities:
Depreciable assets	(5.6)	(5.1)
Inventory fair value step-up	(53.5)	0.0
Investment in foreign partnership	(1,992.7)	(2,249.5)
ROU leases	(51.9)	(53.9)
Total deferred tax liabilities	(2,103.7)	(2,308.5)
Net deferred tax (liability) asset	$ 567.2	$ 208.8

Income Taxes (Summary of Valuation Allowance) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets, Valuation Allowance [Roll Forward]
Valuation allowance, beginning balance	$ (72.6)	$ (19.6)	$ (3.4)
Additions charged to income tax expense	(18.8)	(68.6)	0.0
Additions charged to acquired in-process research and development			(17.1)
Reductions credited to income tax expense	0.0	15.6	0.9
Additions charged to goodwill	(184.6)
Valuation allowance, ending balance	$ (276.0)	$ (72.6)	$ (19.6)

Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning of period balance	$ 133.8	$ 92.7	$ 60.9
Increases for tax positions taken during a prior period	27.6	3.4	9.1
Decreases for tax positions taken during a prior period	(10.0)	(4.9)	(5.8)
Increases for tax positions taken during the current period	28.0	43.8	28.8
Decreases for tax positions related to settlements	(13.9)	0.0	0.0
Decreases for tax positions related to lapse of statute	(2.1)	(1.2)	(0.3)
End of period balance	$ 163.4	$ 133.8	$ 92.7

Share-based Compensation (Narrative) (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) year $ / shares shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award
Maximum contractual term under all plans (in years) \| year	10
Total intrinsic value of stock options exercised \| $	$ 39.3	$ 14.7	$ 27.5
Fair value of options vested \| $	$ 4.8	10.1	27.2
Restricted Stock, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	$ 100.95
Restricted Stock, Grants in Period \| shares	3.9
Shares vested \| shares	2.2
Allocated Share-based Compensation Expense \| $	$ 281.1	$ 237.0	$ 203.0
Total compensation cost not yet recognized on non-vested awards \| $	$ 366.3
Period for rececognition for compensation cost not yet recognized of non-vested awards	1 year 8 months 4 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award
Restricted Stock, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	$ 100.95	$ 133.89	$ 119.27
Restricted Stock, Vested in Period, Weighted Average Grant Date Fair Value \| $	$ 271.3	$ 161.3	$ 181.7
Performance-based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award
Restricted Stock, Grants in Period \| shares	0.3
Replacement Awards \| Portola Pharmaceuticals
Share-based Compensation Arrangement by Share-based Payment Award
Restricted Stock, Grants in Period \| shares	0.4
Restricted Stock And Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award
Restricted Stock, Vested in Period, Weighted Average Grant Date Fair Value \| $	$ 71.8
Shares vested \| shares	0.6
Market-Based Performance
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense \| $	$ 66.6	46.3	14.9
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award
Maximum shares authorized \| shares	1.0
Inventory
Share-based Compensation Arrangement by Share-based Payment Award
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount \| $	$ 11.9	$ 12.9	$ 14.5
Senior Management
Share-based Compensation Arrangement by Share-based Payment Award
Restricted Stock, Grants in Period \| shares	0.5
Senior Management \| Market-Based Performance
Share-based Compensation Arrangement by Share-based Payment Award
Restricted Stock, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	$ 94.03
2017 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award
Maximum shares authorized \| shares	18.2
2017 Equity Plan \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award
General vesting period (in years)	4 years
2017 Equity Plan \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award
General vesting period (in years)	4 years
2017 Equity Plan \| Performance-based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award
General vesting period (in years)	3 years

Share-based Compensation (Schedule of Components of Allocated Share-Based Compensation Expense and Capitalization of Share Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	$ 281.1	$ 237.0	$ 203.0
Income tax effect	(65.3)	(55.0)	(46.5)
Total share-based compensation expense, net of tax	215.8	182.0	156.5
Cost of sales (exclusive of amortization of purchased intangible assets)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	12.4	14.1	16.0
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	68.6	61.8	57.5
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	179.7	161.1	129.5
Acquisition-related Costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	$ 20.4	$ 0.0	$ 0.0

Share-based Compensation (Schedule of Status of Stock Option Plans) (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period, Number of shares \| shares	3.0
Granted, Number of shares \| shares	0.0
Exercised, Number of shares \| shares	(0.7)
Forfeited and cancelled, Number of shares \| shares	(0.1)
Outstanding at end of period, Number of shares \| shares	2.2
Vested and unvested expected to vest at end of period, Number of shares \| shares	2.2
Exercisable at end of period, Number of shares \| shares	2.2
Outstanding at beginning of period, Weighted Average Exercise Price \| $ / shares	$ 119.51
Granted, Weighted Average Exercise Price \| $ / shares	75.10
Exercised, Weighted Average Exercise Price \| $ / shares	64.79
Forfeited and cancelled, Weighted Average Exercise Price \| $ / shares	146.19
Outstanding at end of period, Weighted Average Exercise Price \| $ / shares	134.15
Vested and unvested expected to vest at end of period, Weighted Average Exercise Price \| $ / shares	134.15
Exercisable at end of period, Weighted Average Exercise Price \| $ / shares	$ 134.35
Outstanding at end of period, Weighted Average Remaining Contractual Term (in years)	3 years 6 months 7 days
Vested and unvested expected to vest at end of period, Weighted Average Remaining Contractual Term (in years)	3 years 6 months 7 days
Exercisable at end of period, Weighted Average Remaining Contractual Term (in years)	3 years 5 months 26 days
Outstanding at end of period, Aggregate Intrinsic Value \| $	$ 67.3
Vested and unvested expected to vest at end of period, Aggregate Intrinsic Value \| $	67.2
Exercisable at end of period, Aggregate Intrinsic Value \| $	$ 66.3

Share-based Compensation (Schedule of Status of Non-Vested Restricted Stock) (Details) shares in Millions	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted stock, beginning of period \| shares	4.3
Shares granted \| shares	3.9
Shares forfeited \| shares	(0.6)
Shares vested \| shares	(2.2)
Nonvested restricted stock, end of period \| shares	5.4
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average grant date fair value \| $ / shares	$ 128.24
Restricted Stock, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	100.95
Forfeited, Weighted average grant date fair value \| $ / shares	119.07
Vested, Weighted average grant date fair value \| $ / shares	122.86
Weighted average grant date fair value \| $ / shares	$ 111.54

Stockholders' Equity (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 28, 2020	Oct. 22, 2019	Feb. 28, 2017
Class of Stock
Repurchase of common stock, shares	4.9	3.8
Repurchase of common stock	$ 510.8	$ 416.0	$ 85.0
Common Stock
Class of Stock
Stock Repurchase Program, Authorized Amount				$ 1,500.0	$ 1,000.0	$ 1,000.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 2,024.7

Other Comprehensive Income and Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated comprehensive income (loss), Beginning balance	$ (66.8)	$ (9.7)	$ (34.4)
Other comprehensive income (loss) before reclassifications	(83.8)	(18.5)	34.0
Amounts reclassified from other comprehensive income	26.0	(38.6)	(9.3)
Other comprehensive (loss) income, net of tax	(57.8)	(57.1)	24.7
Accumulated comprehensive income (loss), Ending balance	(124.6)	(66.8)	(9.7)
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated comprehensive income (loss), Beginning balance	(9.2)	(2.6)	(4.8)
Other comprehensive income (loss) before reclassifications	(1.5)	(6.6)	1.5
Amounts reclassified from other comprehensive income	0.5	0.0	0.7
Other comprehensive (loss) income, net of tax	(1.0)	(6.6)	2.2
Accumulated comprehensive income (loss), Ending balance	(10.2)	(9.2)	(2.6)
Unrealized Gains (Losses) from Debt Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated comprehensive income (loss), Beginning balance	(0.1)	(0.3)	0.2
Other comprehensive income (loss) before reclassifications	0.1	0.2	0.1
Amounts reclassified from other comprehensive income	0.0	0.0	(0.6)
Other comprehensive (loss) income, net of tax	0.1	0.2	(0.5)
Accumulated comprehensive income (loss), Ending balance	0.0	(0.1)	(0.3)
Unrealized Gains (Losses) from Hedging Activities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated comprehensive income (loss), Beginning balance	(40.1)	9.6	(13.9)
Other comprehensive income (loss) before reclassifications	(88.1)	(11.1)	32.9
Amounts reclassified from other comprehensive income	25.5	(38.6)	(9.4)
Other comprehensive (loss) income, net of tax	(62.6)	(49.7)	23.5
Accumulated comprehensive income (loss), Ending balance	(102.7)	(40.1)	9.6
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated comprehensive income (loss), Beginning balance	(17.4)	(16.4)	(15.9)
Other comprehensive income (loss) before reclassifications	5.7	(1.0)	(0.5)
Amounts reclassified from other comprehensive income	0.0	0.0	0.0
Other comprehensive (loss) income, net of tax	5.7	(1.0)	(0.5)
Accumulated comprehensive income (loss), Ending balance	$ (11.7)	$ (17.4)	$ (16.4)

Other Comprehensive Income and Accumulated Other Comprehensive Income (Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification out of Accumulated Other Comprehensive Income
Total revenues	$ 1,591.8	$ 1,588.7	$ 1,444.6	$ 1,444.8	$ 1,384.3	$ 1,263.1	$ 1,203.3	$ 1,140.4	$ 6,069.9	$ 4,991.1	$ 4,131.2
Interest expense									(104.7)	(77.8)	(98.2)
Income before income taxes									569.0	2,178.8	242.2
Income tax (benefit) expense									34.4	225.5	(164.6)
Net income	$ 535.8	$ 578.1	$ (1,068.1)	$ 557.6	$ 889.0	$ 467.6	$ 459.8	$ 587.9	603.4	2,404.3	77.6
Reclassification from accumulated other comprehensive income, net									(26.0)	38.6	9.3
Unrealized Gains (Losses) from Hedging Activities
Reclassification out of Accumulated Other Comprehensive Income
Reclassification from accumulated other comprehensive income, net									(25.5)	38.6	9.4
Amortization of prior service costs and actuarial losses
Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax									(0.7)	0.0	(0.3)
Curtailment
Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax									0.0	0.0	(0.6)
Defined Benefit Pension Plans
Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax									(0.7)	0.0	(0.9)
Income tax (benefit) expense									(0.2)	0.0	(0.2)
Reclassification from accumulated other comprehensive income, net									(0.5)	0.0	(0.7)
Reclassification out of Accumulated Other Comprehensive Income \| Unrealized Gains (Losses) from Hedging Activities
Reclassification out of Accumulated Other Comprehensive Income
Income before income taxes									(32.8)	50.1	11.8
Income tax (benefit) expense									7.3	(11.5)	(2.4)
Net income									(25.5)	38.6	9.4
Reclassification out of Accumulated Other Comprehensive Income \| Interest rate swap contracts \| Unrealized Gains (Losses) from Hedging Activities
Reclassification out of Accumulated Other Comprehensive Income
Interest expense									(37.5)	13.3	13.6
Net Product Sales
Reclassification out of Accumulated Other Comprehensive Income
Total revenues									6,069.1	4,990.0	4,130.1
Net Product Sales \| Reclassification out of Accumulated Other Comprehensive Income \| Forward exchange forward contracts \| Unrealized Gains (Losses) from Hedging Activities
Reclassification out of Accumulated Other Comprehensive Income
Total revenues									$ 4.7	$ 36.8	$ (1.8)

Fair Value Measurement (Narrative) (Details) - USD ($)		1 Months Ended		12 Months Ended
Fair Value Measurement (Narrative) (Details) - USD ($)	Jan. 28, 2020	Dec. 31, 2019	Jan. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Weighted average cost of capital				11.50%
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low				$ 0
Contingent consideration arrangements, range of outcomes, value, high				905,600,000
Contingent consideration		$ 192,400,000		299,400,000	$ 192,400,000
Business Combination, Contingent Consideration Arrangements, Expected Payments Next Twelve Months				120,000,000.0
Caelum Biosciences \| Collaborative Arrangement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Collaboration Agreement, Upfront Payment			$ 30,000,000.0
Collaboration Agreement, Potential Future Payments, Milestone Achievement			$ 30,000,000.0
Derivative Liability		24,000,000.0			$ 24,000,000.0	$ 27,100,000
Discounted cost of debt					2.10%
Additional upfront funding accrued					$ 20,000,000.0
Additional equity interest funding		60,000,000.0
Collaboration Agreement, Milestone Payment				30,000,000.0
Research and Development Expense				6,000,000.0	3,100,000
Caelum Biosciences \| Collaborative Agreement, Amendment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Research and Development Expense					4,100,000
Acquisition-related contingent consideration \| Contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration				$ 414,300,000
Level 3 \| Acquisition-related contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		$ 192,400,000			$ 192,400,000
Minimum \| Caelum Biosciences \| Collaborative Arrangement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Discounted cost of debt			3.30%
Minimum \| Level 3 \| Acquisition-related contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value inputs, cost of debt	2.10%			2.80%
Weighted average cost of capital				9.00%
Maximum \| Caelum Biosciences \| Collaborative Arrangement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Discounted cost of debt			3.50%
Maximum \| Level 3 \| Acquisition-related contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value inputs, cost of debt	2.30%			3.30%

Fair Value Measurement (Schedule Of Acquisition-Related Contingent Consideration) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Acquisition-Related Contingent Consideration [Roll Forward]
Balance as of December 31, 2019	$ 192.4
Amounts issued	160.7
Balance as of December 31, 2020	299.4
Acquisition-related contingent consideration \| Level 3
Acquisition-Related Contingent Consideration [Roll Forward]
Balance as of December 31, 2019	192.4
Changes in fair value	$ (61.2)

Restructuring and Related Expenses (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Related Cost, Expected Cost	$ 10.0
Restructuring Reserve	$ 8.2	$ 6.8	$ 4.2

Restructuring and Related Expenses - Reconciliation of Restructuring Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve
Restructuring expenses	$ 10.3	$ 12.0	$ 50.7
Restructuring Reserve [Roll Forward]
Liability, beginning of year	6.8	4.2
Charges	16.7	17.2
Settlements	(8.9)	(9.4)
Adjustments to previous estimates	(6.4)	(5.2)
Liability, end of year	8.2	6.8	4.2
Employee Separation Costs
Restructuring Cost and Reserve
Restructuring expenses	8.4	8.4	4.6
Restructuring Reserve [Roll Forward]
Liability, beginning of year	3.3	4.2
Charges	14.3	14.2
Settlements	(3.5)	(9.3)
Adjustments to previous estimates	(5.9)	(5.8)
Liability, end of year	8.2	3.3	4.2
Asset-Related Charges
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	25.3
Other
Restructuring Cost and Reserve
Restructuring expenses	1.9	3.6	20.8
Restructuring Reserve [Roll Forward]
Liability, beginning of year	3.5	0.0
Charges	2.4	3.0
Settlements	(5.4)	(0.1)
Adjustments to previous estimates	(0.5)	0.6
Liability, end of year	0.0	3.5	0.0
Cost of sales (exclusive of amortization of purchased intangible assets)
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	5.8
Cost of sales (exclusive of amortization of purchased intangible assets) \| Employee Separation Costs
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Cost of sales (exclusive of amortization of purchased intangible assets) \| Asset-Related Charges
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	5.8
Cost of sales (exclusive of amortization of purchased intangible assets) \| Other
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Research and development
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.1
Research and development \| Employee Separation Costs
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Research and development \| Asset-Related Charges
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.1
Research and development \| Other
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Selling, general and administrative
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	19.4
Selling, general and administrative \| Employee Separation Costs
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Selling, general and administrative \| Asset-Related Charges
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	19.4
Selling, general and administrative \| Other
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Restructuring expenses
Restructuring Cost and Reserve
Restructuring expenses	10.3	12.0	25.5
Restructuring expenses \| Employee Separation Costs
Restructuring Cost and Reserve
Restructuring expenses	8.4	8.4	4.6
Restructuring expenses \| Asset-Related Charges
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Restructuring expenses \| Other
Restructuring Cost and Reserve
Restructuring expenses	1.9	3.6	20.9
Other income and (expense)
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	(0.1)
Other income and (expense) \| Employee Separation Costs
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0	0.0
Other income and (expense) \| Asset-Related Charges
Restructuring Cost and Reserve
Restructuring expenses	0.0	0.0
Other income and (expense) \| Other
Restructuring Cost and Reserve
Restructuring expenses	$ 0.0	$ 0.0	$ (0.1)

Segment Information - Net Product Sales (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from External Customer
Total revenues	$ 1,591.8	$ 1,588.7	$ 1,444.6	$ 1,444.8	$ 1,384.3	$ 1,263.1	$ 1,203.3	$ 1,140.4	$ 6,069.9	$ 4,991.1	$ 4,131.2
Long-Lived Assets	1,238.8				1,163.3				$ 1,238.8	$ 1,163.3
Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									21.60%	20.80%
SOLIRIS
Revenue from External Customer
Total revenues									$ 4,064.2	$ 3,946.4	3,563.0
SOLIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									3.00%	10.80%
ULTOMIRIS
Revenue from External Customer
Total revenues									$ 1,076.7	$ 338.9	0.0
STRENSIQ
Revenue from External Customer
Total revenues									$ 731.8	$ 592.5	475.1
STRENSIQ \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									23.50%	24.70%
ANDEXXA
Revenue from External Customer
Total revenues									$ 78.5	$ 0.0	0.0
KANUMA
Revenue from External Customer
Total revenues									$ 117.9	$ 112.2	92.0
KANUMA \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									5.10%	22.00%
Total Net Product Sales
Revenue from External Customer
Total revenues									$ 6,069.1	$ 4,990.0	4,130.1
United States
Revenue from External Customer
Long-Lived Assets	261.0				272.8				261.0	272.8
United States \| SOLIRIS
Revenue from External Customer
Total revenues									$ 2,259.7	$ 2,014.0	1,588.4
United States \| SOLIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									12.20%	26.80%
United States \| ULTOMIRIS
Revenue from External Customer
Total revenues									$ 646.0	$ 236.8	0.0
United States \| ULTOMIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									172.80%
United States \| STRENSIQ
Revenue from External Customer
Total revenues									$ 562.9	$ 451.7	374.3
United States \| STRENSIQ \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									24.60%	20.70%
United States \| ANDEXXA
Revenue from External Customer
Total revenues									$ 71.7	$ 0.0	0.0
United States \| KANUMA
Revenue from External Customer
Total revenues									$ 63.7	$ 60.0	51.3
United States \| KANUMA \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									6.20%	17.00%
Europe
Revenue from External Customer
Long-Lived Assets	976.2				889.6				$ 976.2	$ 889.6
Europe \| SOLIRIS
Revenue from External Customer
Total revenues									$ 1,033.3	$ 1,049.8	1,036.7
Europe \| SOLIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									(1.60%)	1.30%
Europe \| ULTOMIRIS
Revenue from External Customer
Total revenues									$ 170.4	$ 52.2	0.0
Europe \| ULTOMIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									226.40%
Europe \| STRENSIQ
Revenue from External Customer
Total revenues									$ 80.8	$ 77.0	61.7
Europe \| STRENSIQ \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									4.90%	24.80%
Europe \| ANDEXXA
Revenue from External Customer
Total revenues									$ 6.8	$ 0.0	0.0
Europe \| KANUMA
Revenue from External Customer
Total revenues									$ 35.6	$ 27.1	21.6
Europe \| KANUMA \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									31.40%	25.50%
Asia Pacific \| SOLIRIS
Revenue from External Customer
Total revenues									$ 343.0	$ 423.5	382.0
Asia Pacific \| SOLIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									(19.00%)	10.90%
Asia Pacific \| ULTOMIRIS
Revenue from External Customer
Total revenues									$ 255.3	$ 49.9	0.0
Asia Pacific \| ULTOMIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									411.60%
Asia Pacific \| STRENSIQ
Revenue from External Customer
Total revenues									$ 61.0	$ 50.4	27.9
Asia Pacific \| STRENSIQ \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									21.00%	80.60%
Asia Pacific \| ANDEXXA
Revenue from External Customer
Total revenues									$ 0.0	$ 0.0	0.0
Asia Pacific \| KANUMA
Revenue from External Customer
Total revenues									$ 4.3	$ 4.6	3.7
Asia Pacific \| KANUMA \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									(6.50%)	24.30%
Rest of World \| SOLIRIS
Revenue from External Customer
Total revenues									$ 428.2	$ 459.1	555.9
Rest of World \| SOLIRIS \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									(6.70%)	(17.40%)
Rest of World \| ULTOMIRIS
Revenue from External Customer
Total revenues									$ 5.0	$ 0.0	0.0
Rest of World \| STRENSIQ
Revenue from External Customer
Total revenues									$ 27.1	$ 13.4	11.2
Rest of World \| STRENSIQ \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									102.20%	19.60%
Rest of World \| ANDEXXA
Revenue from External Customer
Total revenues									$ 0.0	$ 0.0	0.0
Rest of World \| KANUMA
Revenue from External Customer
Total revenues									$ 14.3	$ 20.5	$ 15.4
Rest of World \| KANUMA \| Sales Revenue, Net \| Geographic Concentration Risk
Revenue from External Customer
Percentage change in product sales									(30.20%)	33.10%
Other
Revenue from External Customer
Long-Lived Assets	$ 1.6				$ 0.9				$ 1.6	$ 0.9

Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information
Total revenues	$ 1,591.8	$ 1,588.7	$ 1,444.6	$ 1,444.8	$ 1,384.3	$ 1,263.1	$ 1,203.3	$ 1,140.4	$ 6,069.9	$ 4,991.1	$ 4,131.2
Cost of sales (exclusive of amortization of purchased intangible assets)	152.2	144.7	144.9	111.7	114.3	95.2	99.2	85.8	553.5	394.5	374.3
Gross profit	1,439.6	1,444.0	1,299.7	1,333.1	1,270.0	1,167.9	1,104.1	1,054.6
Operating expenses	817.5	759.1	2,669.9	637.6	729.0	637.9	571.5	537.8
Operating income (loss)	622.1	684.9	(1,370.2)	695.5	541.0	530.0	532.6	516.8	632.3	2,120.4	269.6
Net income	$ 535.8	$ 578.1	$ (1,068.1)	$ 557.6	$ 889.0	$ 467.6	$ 459.8	$ 587.9	$ 603.4	$ 2,404.3	$ 77.6
Earnings per common share
Basic (in dollars per share)	$ 2.45	$ 2.64	$ (4.84)	$ 2.52	$ 4.02	$ 2.09	$ 2.05	$ 2.63	$ 2.74	$ 10.77	$ 0.35
Diluted (in dollars per share)	$ 2.42	$ 2.62	$ (4.84)	$ 2.50	$ 4.00	$ 2.08	$ 2.04	$ 2.61	$ 2.72	$ 10.70	$ 0.35
Deferred tax benefit									$ 283.4	$ 455.5	$ (32.9)
Deferred tax benefit, asset transfer					$ 382.2
Purchased technology
Earnings per common share
Impairment of indefinite-lived intangible assets									$ 2,042.3
Intellectual Property Election \| Wilson Therapeutics
Earnings per common share
Deferred tax benefit								$ 95.7		95.7
Valuation Allowance Release
Earnings per common share
Deferred tax benefit										$ 30.3
Valuation Allowance Release \| Wilson Therapeutics
Earnings per common share
Deferred tax benefit								$ 30.3

Subsequent Events (Details) $ in Millions	1 Months Ended
Subsequent Events (Details) $ in Millions	Jan. 31, 2021 USD ($)
Subsequent Event
Subsequent Event
Total consideration	$ 100.0

Fair Value Measurement (Schedule Of Assets And Liabilites Measured At Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Current portion of contingent consideration	$ 114.9	$ 0.0
Contingent consideration	299.4	192.4
Acquisition-related contingent consideration \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		192.4
Cash equivalents \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	833.7	635.9
Cash equivalents \| Money market funds \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	0.0	0.0
Cash equivalents \| Money market funds \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	833.7	635.9
Cash equivalents \| Money market funds \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	0.0	0.0
Cash equivalents \| Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		20.6
Cash equivalents \| Corporate bonds \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Corporate bonds \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		20.6
Cash equivalents \| Corporate bonds \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		227.9
Cash equivalents \| Commercial paper \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Commercial paper \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		227.9
Cash equivalents \| Commercial paper \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Bank certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		19.2
Cash equivalents \| Bank certificates of deposit \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Bank certificates of deposit \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		19.2
Cash equivalents \| Bank certificates of deposit \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Other government-related obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		60.4
Cash equivalents \| Other government-related obligations \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Cash equivalents \| Other government-related obligations \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		60.4
Cash equivalents \| Other government-related obligations \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0.0
Marketable securities \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	34.9	23.1
Marketable securities \| Mutual funds \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	34.9	23.1
Marketable securities \| Mutual funds \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	0.0	0.0
Marketable securities \| Mutual funds \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	0.0	0.0
Marketable securities \| Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		3.7
Marketable securities \| Corporate bonds \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Corporate bonds \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		3.7
Marketable securities \| Corporate bonds \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		19.0
Marketable securities \| Commercial paper \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Commercial paper \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		19.0
Marketable securities \| Commercial paper \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Bank certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		8.2
Marketable securities \| Bank certificates of deposit \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Bank certificates of deposit \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		8.2
Marketable securities \| Bank certificates of deposit \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Other government-related obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		10.0
Marketable securities \| Other government-related obligations \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Marketable securities \| Other government-related obligations \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		10.0
Marketable securities \| Other government-related obligations \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure		0.0
Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure
Other assets \| Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	143.2	79.0
Other assets \| Equity securities \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	122.7	51.2
Other assets \| Equity securities \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	20.5	27.8
Other assets \| Equity securities \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Investments, Fair Value Disclosure	0.0	0.0
Other assets \| Foreign exchange forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset		0.6
Other assets \| Foreign exchange forward contracts \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset		0.0
Other assets \| Foreign exchange forward contracts \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset		0.6
Other assets \| Foreign exchange forward contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset		0.0
Prepaid expenses and other current assets \| Foreign exchange forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset	26.1	29.9
Prepaid expenses and other current assets \| Foreign exchange forward contracts \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset	0.0	0.0
Prepaid expenses and other current assets \| Foreign exchange forward contracts \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset	26.1	29.9
Prepaid expenses and other current assets \| Foreign exchange forward contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, asset	0.0	0.0
Other current liabilities \| Foreign exchange forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	80.1	26.6
Other current liabilities \| Foreign exchange forward contracts \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	0.0	0.0
Other current liabilities \| Foreign exchange forward contracts \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	80.1	26.6
Other current liabilities \| Foreign exchange forward contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	0.0	0.0
Other current liabilities \| Interest rate swap contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	45.9	19.5
Other current liabilities \| Interest rate swap contracts \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	0.0	0.0
Other current liabilities \| Interest rate swap contracts \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	45.9	19.5
Other current liabilities \| Interest rate swap contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	0.0	0.0
Other current liabilities \| Other contingent payments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		24.0
Other current liabilities \| Other contingent payments \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		0.0
Other current liabilities \| Other contingent payments \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		0.0
Other current liabilities \| Other contingent payments \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		24.0
Other liabilities \| Foreign exchange forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	1.2	1.1
Other liabilities \| Foreign exchange forward contracts \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	0.0	0.0
Other liabilities \| Foreign exchange forward contracts \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	1.2	1.1
Other liabilities \| Foreign exchange forward contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign exchange forward contracts, liability	0.0	0.0
Other liabilities \| Interest rate swap contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	45.4	41.9
Other liabilities \| Interest rate swap contracts \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	0.0	0.0
Other liabilities \| Interest rate swap contracts \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	45.4	41.9
Other liabilities \| Interest rate swap contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Derivative Liabilities, at Fair Value	0.0	0.0
Current portion of contingent consideration \| Acquisition-related contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Current portion of contingent consideration	114.9
Current portion of contingent consideration \| Acquisition-related contingent consideration \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Current portion of contingent consideration	0.0
Current portion of contingent consideration \| Acquisition-related contingent consideration \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Current portion of contingent consideration	0.0
Current portion of contingent consideration \| Acquisition-related contingent consideration \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Current portion of contingent consideration	114.9
Contingent consideration \| Acquisition-related contingent consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Noncurrent contingent consideration	299.4	192.4
Contingent consideration	414.3
Contingent consideration \| Acquisition-related contingent consideration \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Noncurrent contingent consideration	0.0	0.0
Contingent consideration \| Acquisition-related contingent consideration \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Noncurrent contingent consideration	0.0	0.0
Contingent consideration \| Acquisition-related contingent consideration \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Noncurrent contingent consideration	$ 299.4	$ 192.4