Consolidated Statements of Shareholders' Equity Statement - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Employee Benefit Trust	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment	Common Stock in Treasury	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2017		1,100,672							664
Beginning balance at Dec. 31, 2017		$ 687.9	$ 5,817.8	$ 13,894.1	$ 763.8	$ (3,013.2)	$ (5,718.6)	$ (105.2)	$ (75.8)	$ 75.7
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income				3,232.0						3.7
Other comprehensive income (loss), net of tax							85.6			(2.0)
Cash dividends declared				(2,372.0)
Retirement of treasury shares (in shares)		(45,882)							(45,882)
Retirement of treasury shares		$ (28.7)		(4,122.0)					$ 4,150.7
Purchase of treasury shares (in shares)									45,882
Purchase of treasury shares	$ (4,150.0)								$ (4,150.7)
Issuance of stock under employee stock plans, net (in shares)		2,849							60
Issuance of stock under employee stock plans, net		$ 1.8	(139.0)						$ 6.4
Stock-based compensation			279.5
Sale of Elanco Stock (Note 19)	1,017.2		629.2				9.0
Other			(3.9)							(14.2)
Ending balance (in shares) at Dec. 31, 2018		1,057,639							604
Ending balance at Dec. 31, 2018		$ 661.0	6,583.6	11,395.9		(3,013.2)	(5,729.2)		$ (69.4)	1,080.4
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income				8,318.4						37.7
Other comprehensive income (loss), net of tax							(794.4)			11.0
Cash dividends declared				(2,430.5)
Retirement of treasury shares (in shares)		(102,640)							(102,640)
Retirement of treasury shares		$ (64.1)		(12,363.4)					$ 12,427.5
Purchase of treasury shares (in shares)									37,639
Purchase of treasury shares	(4,400.0)								$ (4,400.0)
Issuance of stock under employee stock plans, net (in shares)		3,057							74
Issuance of stock under employee stock plans, net		$ 1.9	(210.7)						$ 8.6
Stock-based compensation			312.4
Acquisition of common stock in exchange offer (in shares)									65,001
Acquisition of common stock in exchange offer									$ (8,027.5)
Deconsolidation of Elanco										(1,028.9)
Other										(8.0)
Ending balance (in shares) at Dec. 31, 2019		958,056							530
Ending balance at Dec. 31, 2019	2,699.1	$ 598.8	6,685.3	4,920.4		(3,013.2)	(6,523.6)		$ (60.8)	92.2
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income				6,193.7						126.6
Other comprehensive income (loss), net of tax							27.2
Cash dividends declared				(2,786.2)
Retirement of treasury shares (in shares)		(3,627)							(3,627)
Retirement of treasury shares		$ (2.3)		(497.7)					$ 500.0
Purchase of treasury shares (in shares)									3,627
Purchase of treasury shares	(500.0)								$ (500.0)
Issuance of stock under employee stock plans, net (in shares)		2,648							43
Issuance of stock under employee stock plans, net		$ 1.7	(212.7)						$ 5.1
Stock-based compensation			308.1
Other			(2.2)							(35.2)
Ending balance (in shares) at Dec. 31, 2020		957,077							487
Ending balance at Dec. 31, 2020	$ 5,825.2	$ 598.2	$ 6,778.5	$ 7,830.2		$ (3,013.2)	$ (6,496.4)		$ (55.7)	$ 183.6