Selected Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 6,160.7	$ 5,658.0	$ 5,824.3	$ 5,228.3	$ 5,760.5	$ 5,191.7	$ 5,404.8	$ 4,865.1	$ 22,871.3	$ 21,222.1	$ 19,958.7
Cost of sales	1,624.8	1,566.1	1,551.6	1,327.7	1,466.0	1,400.9	1,465.0	1,323.0	6,070.2	5,654.9	5,037.2
Operating Expenses	3,253.7	2,874.9	2,958.3	2,783.0	3,240.7	2,801.8	2,958.5	2,694.9
Acquired in-process research and development	50.0	205.0	0.0	857.6	30.0	0.0	0.0	0.0	1,112.6	30.0	535.0
Asset impairment, restructuring, and other special charges (Note 5)	1,003.2	406.5	50.0	213.9	147.6	45.5	58.0	131.4	1,673.6	382.5	367.7
Other-net, (income) expense									(52.4)	84.8	(100.6)
Income before income taxes	284.1	591.6	1,260.5	61.2	892.0	970.7	944.5	566.8
Income taxes (Note 13)	1,941.0	36.0	252.5	172.0	120.2	192.7	196.8	126.7	$ 2,401.5	$ 636.4	$ 381.6
Net income (loss)	$ (1,656.9)	$ 555.6	$ 1,008.0	$ (110.8)	$ 771.8	$ 778.0	$ 747.7	$ 440.1
Basic (usd per share)	$ (1.58)	$ 0.53	$ 0.96	$ (0.10)	$ 0.73	$ 0.74	$ 0.71	$ 0.42	$ (0.19)	$ 2.59	$ 2.27
Diluted (usd per share)	(1.58)	0.53	0.95	(0.10)	0.73	0.73	0.71	0.41	(0.19)	2.58	$ 2.26
Dividends paid per share (usd per share)	0.52	0.52	0.52	0.52	0.51	0.51	0.51	0.51
Maximum
Condensed Financial Statements, Captions [Line Items]
Common stock closing prices(usd per share)	87.89	85.54	86.25	85.88	83.06	83.4	78.75	84.11	87.89	83.06
Minimum
Condensed Financial Statements, Captions [Line Items]
Common stock closing prices(usd per share)	$ 81.94	$ 77.07	$ 76.98	$ 74.58	$ 65.97	$ 76.85	$ 72.57	$ 69.06	$ 81.94	$ 65.97