Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 2,670.1	$ 3,695.7	$ 3,593.2
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	1,081.0	682.7	600.4
Acquired in-process research and development	120.0	0.0	0.0
Share-based compensation	128.0	154.8	161.4
Deferred income taxes	91.7	(175.0)	(145.6)
Loss (gain) on fair value remeasurement of contingent consideration	62.7	14.8	30.5
Other	162.1	89.0	129.9
Changes in operating assets and liabilities, net:
Accounts receivable	(435.6)	(241.4)	29.0
Due from anti-CD20 therapeutic programs	(232.0)	13.9	(31.1)
Inventory	(94.5)	(165.6)	(174.4)
Other assets	(76.6)	59.1	(127.0)
Accrued expenses and other current liabilities	(227.4)	622.3	199.3
Income tax assets and liabilities	1,303.9	(232.6)	(429.4)
Other liabilities	(2.4)	69.5	83.2
Net cash flows provided by operating activities	4,551.0	4,587.2	3,919.4
Cash flows from investing activities:
Proceeds from sales and maturities of marketable securities	5,565.9	7,378.9	4,063.0
Purchases of marketable securities	(5,355.2)	(7,913.2)	(6,864.9)
Contingent consideration related to Fumapharm AG acquisition	(1,200.0)	(1,200.0)	(850.0)
Payments to Acquire in Process Research and Development	(120.0)	0.0	0.0
Acquisitions of businesses, net of cash acquired	0.0	0.0	(198.8)
Purchases of property, plant and equipment	(867.4)	(616.1)	(643.0)
Acquisitions of intangible assets	(975.4)	(111.6)	(15.4)
Other	(11.0)	(22.8)	(44.5)
Net cash flows used in investing activities	(2,963.1)	(2,484.8)	(4,553.6)
Cash flows from financing activities:
Purchases of treasury stock	(1,365.4)	(1,000.0)	(5,000.0)
Payments related to issuance of stock for share-based compensation arrangements, net	(5.3)	(8.5)	(70.9)
Net distribution to noncontrolling interest	(134.1)	0.0	(56.1)
Proceeds from borrowings	0.0	0.0	5,930.5
Repayments of borrowings	(560.9)	(2.7)	(2.1)
Net cash contribution to Bioverativ, Inc.	(302.7)	0.0	0.0
Contingent consideration payments	(3.0)	(38.6)	(13.1)
Other	(8.6)	(2.8)	(5.2)
Net cash flows provided by (used in) financing activities	(2,380.0)	(1,052.6)	783.1
Net increase in cash and cash equivalents	(792.1)	1,049.8	148.9
Effect of exchange rate changes on cash and cash equivalents	39.4	(31.3)	(45.8)
Cash and cash equivalents, beginning of the year	2,326.5	1,308.0	1,204.9
Cash and cash equivalents, end of the year	$ 1,573.8	$ 2,326.5	$ 1,308.0