Consolidated Statements of Shareholders' Equity Statement - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Employee Benefit Trust	Accumulated Other Comprehensive Loss	Common Stock in Treasury	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2016		1,101,586					711
Beginning balance at Dec. 31, 2016		$ 688.5	$ 5,640.6	$ 16,046.3	$ (3,013.2)	$ (5,274.0)	$ (80.5)	$ 72.8
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income (loss)				(204.1)				30.5
Other comprehensive income (loss), net of tax						199.0		(24.5)
Cash dividends declared				(2,234.6)
Retirement of treasury shares (in shares)		(4,390)					(4,390)
Retirement of treasury shares		$ (2.7)		(357.1)			$ 359.8
Purchase of treasury shares	$ (359.8)		60.0				$ (359.8)
Purchase of treasury shares (in shares)							4,390
Issuance of stock under employee stock plans, net (in shares)		3,476					(47)
Issuance of stock under employee stock plans, net		$ 2.1	(164.1)				$ 4.7
Stock-based compensation			281.3
Reclassification of stranded tax effects (Note 1)	(643.6)			643.6		(643.6)
Other								(3.1)
Ending balance (in shares) at Dec. 31, 2017		1,100,672					664
Ending balance at Dec. 31, 2017		$ 687.9	5,817.8	13,894.1	(3,013.2)	(5,718.6)	$ (75.8)	75.7
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income (loss)				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	(4,150.0)						$ (4,150.7)
Purchase of treasury shares (in shares)							45,882
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)			629.2			9.0		1,017.2
Other			(3.9)					(14.2)
Ending balance (in shares) at Dec. 31, 2018		1,057,639					604
Ending balance at Dec. 31, 2018	10,909.1	$ 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 (loss)				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	(4,400.0)						$ (4,400.0)
Purchase of treasury shares (in shares)							37,639
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