Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 1,171.2	$ 747.5
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	168.9	512.0
Acquired in-process research and development	10.0	0.0
Share-based compensation	43.4	37.0
Deferred income taxes	53.1	76.1
Other	26.1	18.1
Changes in operating assets and liabilities, net:
Accounts receivable	(134.0)	(195.7)
Inventory	2.6	(46.2)
Accrued expenses and other current liabilities	(121.8)	(684.2)
Income tax assets and liabilities	257.6	(195.1)
Other changes in operating assets and liabilities, net	(20.0)	(34.3)
Net cash flows provided by operating activities	1,457.1	235.2
Cash flows from investing activities:
Proceeds from sales and maturities of marketable securities	4,068.9	1,884.3
Purchases of marketable securities	(1,919.2)	(1,256.7)
Contingent consideration paid related to Fumapharm AG acquisition	600.0	300.0
Purchases of property, plant and equipment	(194.7)	(210.0)
Acquired in-process research and development	(10.0)	0.0
Acquisitions of intangible assets	0.0	(855.2)
Other	1.6	(6.6)
Net cash flows provided by (used in) investing activities	1,346.6	(744.2)
Cash flows from financing activities:
Purchases of treasury stock	(250.0)	(583.6)
Payments related to issuance of stock for share-based compensation arrangements, net	(21.2)	(25.5)
Net cash contribution to Bioverativ Inc.	0.0	302.7
Other	2.6	10.4
Net cash flows used in financing activities	(268.6)	(901.4)
Net (decrease) increase in cash and cash equivalents	2,535.1	(1,410.4)
Effect of exchange rate changes on cash and cash equivalents	(0.9)	7.9
Cash and cash equivalents, beginning of the period	1,573.8	2,326.5
Cash and cash equivalents, end of the period	$ 4,108.0	$ 924.0