Consolidated and Combined Statements of Equity - USD ($) shares in Millions, $ in Millions		Total		Cumulative Effect, Period of Adoption, Adjustment		Common Stock	Additional Paid-in Capital	Net Parent Company Investment	Net Parent Company Investment Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative Effect, Period of Adoption, Adjustment	[3]	Cash Flow Hedge	Foreign Currency Translation	Defined Benefit Pension and Retiree Health Benefit Plans	Total	Total Cumulative Effect, Period of Adoption, Adjustment	[3]
Balance at beginning of period (in shares) at Dec. 31, 2017						293.3
Balance at beginning of period at Dec. 31, 2017		$ 7,780.3		$ (0.3)		$ 0.0	$ 0.0	$ 8,036.9	$ (0.3)	$ 0.0			$ 0.0	$ (227.2)	$ (29.4)	$ (256.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		86.5						70.1		16.4
Other comprehensive income (loss), net of tax		(21.7)												(47.1)	25.4	(21.7)
Transfers (to)/from Lilly, net		(226.3)						(226.3)
Separation adjustments	[1]	99.6						43.5						56.1		56.1
Issuance of common stock (in shares)						72.3
Issuance of common stock		1,659.7					1,659.7
Consideration to Lilly in connection with Separation		(4,194.9)					(4,194.9)
Reclassification of net parent company investment		0.0					7,923.9	(7,923.9)
Stock compensation		1.8					1.8
Capital contribution from Lilly		12.8					12.8
Balance at end of period (in shares) at Dec. 31, 2018						365.6
Balance at end of period at Dec. 31, 2018		5,197.5				$ 0.0	5,403.3	0.0		16.4			0.0	(218.2)	(4.0)	(222.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		67.9								67.9
Other comprehensive income (loss), net of tax		48.5												19.8	28.7	48.5
Separation adjustments	[2]	(51.2)					(51.2)									0.0
Stock compensation		40.7					40.7
Issuance of stock under employee stock plans, net (in shares)						0.1
Issuance of shares for acquisition (in shares)						7.2
Issuance of shares for acquisition		238.0					238.0
Accelerated vesting of equity awards (in shares)						0.1
Accelerated vesting of equity awards		3.6					3.6
Other		1.9					1.9
Balance at end of period (in shares) at Dec. 31, 2019						373.0
Balance at end of period at Dec. 31, 2019		$ 5,546.9		$ (1.4)	[3]	$ 0.0	5,636.3	0.0		84.3	$ (1.4)		0.0	(198.4)	24.7	(173.7)	$ 0.0
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		$ (560.1)								(560.1)
Other comprehensive income (loss), net of tax		476.7	[2]										(60.4)	558.2	(21.1)	476.7
Separation adjustments	[2]	38.0					38.0
Stock compensation		47.7					47.7
Issuance of stock under employee stock plans, net (in shares)						1.0
Issuance of stock under employee stock plans, net		(14.4)					(14.4)
Issuance of common stock and tangible equity units, net of issuance costs (in shares)						25.0
Issuance of common stock and tangible equity units, net of issuance costs		1,220.0	[3]				1,220.0
Issuance of shares for acquisition (in shares)						72.9
Issuance of shares for acquisition		1,722.8	[3]				1,722.8
Other		(0.3)	[3]				(0.3)
Balance at end of period (in shares) at Dec. 31, 2020						471.9
Balance at end of period at Dec. 31, 2020		$ 8,475.9				$ 0.0	$ 8,650.1	$ 0.0		$ (477.2)			$ (60.4)	$ 359.8	$ 3.6	$ 303.0

[1] See Note 3: Impact of Separation for further discussion.

[2] See Note 21: Related Party Agreements and Transactions for further discussion.

[3] See Note 4: Summary of Significant Accounting Policies for further discussion.