Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 24,539.8	$ 22,319.5	$ 21,493.3
Costs, expenses, and other:
Cost of sales	5,483.3	4,721.2	4,681.7
Research and development	6,085.7	5,595.0	5,051.2
Marketing, selling, and administrative	6,121.2	6,213.8	5,975.1
Acquired in-process research and development (Note 3)	660.4	239.6	1,983.9
Asset impairment, restructuring, and other special charges (Note 5)	131.2	575.6	266.9
Other—net, (income) expense (Note 18)	(1,171.9)	(291.6)	(145.6)
Costs, expenses, and other	17,309.9	17,053.6	17,813.2
Income before income taxes	7,229.9	5,265.9	3,680.1
Income taxes (Note 14)	1,036.2	628.0	529.5
Net income from continuing operations	6,193.7	4,637.9	3,150.6
Net income from discontinued operations (Note 19)	0.0	3,680.5	81.4
Net income	$ 6,193.7	$ 8,318.4	$ 3,232.0
Earnings per share:
Earnings from continuing operations - basic (in usd per share)	$ 6.82	$ 4.98	$ 3.07
Earnings from discontinued operations - basic (in usd per share)	0	3.95	0.07
Earnings per share - basic (in usd per share)	6.82	8.93	3.14
Earnings from continuing operations - diluted (in usd per share)	6.79	4.96	3.05
Earnings from discontinued operations - diluted (in usd per share)	0	3.93	0.08
Earnings per share - diluted (in usd per share)	$ 6.79	$ 8.89	$ 3.13
Shares used in calculation of earnings per share:
Basic (in shares)	907,634	931,059	1,027,721
Diluted (in shares)	912,505	935,684	1,033,667