Selected Quarterly Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 6,114.0	$ 5,476.6	$ 5,636.7	$ 5,092.2	$ 5,637.6	$ 5,306.9	$ 5,585.0	$ 4,963.8	$ 22,319.5	$ 21,493.3	$ 19,973.8
Cost of sales	1,282.6	1,175.0	1,124.9	1,138.7	1,129.9	1,152.9	1,234.3	1,164.6	4,721.2	4,681.7	4,447.7
Operating expenses	3,279.5	2,793.2	2,988.5	2,747.6	3,085.5	2,738.1	2,756.6	2,446.2
Acquired IPR&D	0.0	77.7	25.0	136.9	329.4	30.0	1,624.5	0.0	239.6	1,983.9	1,112.6
Asset impairment, restructuring, and other special charges	151.7	0.0	0.0	423.9	192.7	42.9	(25.5)	56.8	575.6	266.9	1,331.6
Income before income taxes	1,663.1	1,405.8	1,465.9	731.1	931.6	1,341.1	41.7	1,365.7
Income taxes	167.4	151.9	138.7	170.0	(189.8)	247.5	273.3	198.5	628.0	529.5	2,391.2
Net income (loss) from continuing operations	1,495.7	1,253.9	1,327.2	561.1	1,121.4	1,093.6	(231.6)	1,167.2	4,637.9	3,150.6	(86.4)
Net income (loss) from discontinued operations	0.0	0.0	0.0	3,680.5	3.7	55.9	(28.3)	50.2	$ 3,680.5	$ 81.4	$ (117.7)
Net income	$ 1,495.7	$ 1,253.9	$ 1,327.2	$ 4,241.6	$ 1,125.1	$ 1,149.5	$ (259.9)	$ 1,217.4
Earnings (loss) from continuing operations - basic (in usd per share)	$ 1.64	$ 1.37	$ 1.44	$ 0.57	$ 1.11	$ 1.07	$ (0.22)	$ 1.11	$ 4.98	$ 3.07	$ (0.08)
Earnings (loss) from discontinued operations - basic (in usd per share)	0	0	0	3.76	0	0.06	(0.03)	0.05	3.95	0.07	(0.11)
Earnings (loss) per share - basic (in usd per share)	1.64	1.37	1.44	4.33	1.11	1.13	(0.25)	1.16	8.93	3.14	(0.19)
Earnings (loss) from continuing operations - diluted (in usd per share)	1.64	1.37	1.44	0.57	1.10	1.07	(0.22)	1.11	4.96	3.05	(0.08)
Earnings (loss) from discontinued operations - diluted (in usd per share)	0	0	0	3.74	0	0.05	(0.03)	0.05	3.93	0.08	(0.11)
Earnings (loss) per share - diluted (in usd per share)	1.64	1.37	1.44	4.31	1.10	1.12	(0.25)	1.16	$ 8.89	$ 3.13	$ (0.19)
Dividends paid per share (in usd per share)	$ 0.6450	$ 0.6450	$ 0.6450	$ 0.6450	$ 0.5625	$ 0.5625	$ 0.5625	$ 0.5625