Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2020		Sep. 30, 2020		Jun. 30, 2020	[3]	Mar. 31, 2020		Dec. 31, 2019		Sep. 28, 2019		Jun. 29, 2019		Mar. 30, 2019		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,289.5	[1]	$ 1,213.7	[2]	$ 1,219.1		$ 1,341.0		$ 1,322.8	[4]	$ 1,191.1	[5]	$ 1,149.0	[6]	$ 1,174.5	[7]	$ 5,063.3	[8]	$ 4,837.4	[8]	$ 4,731.7	[8]
Gross profit	469.2	[1]	428.1	[2]	434.7		483.2		480.9	[4]	412.8	[5]	430.8	[6]	448.8	[7]	1,815.2		1,773.3		1,831.5
Change in financial assets	122.3	[1]	(22.2)	[2]	(2.1)		(1.6)		(3.6)	[4]	(2.6)	[5]	(5.5)	[6]	(10.4)	[7]	96.4		(22.1)		(188.7)
Net income (loss)	$ (175.0)	[1]	$ (154.6)	[2]	$ 60.6		$ 106.4		$ (19.0)	[4]	$ 92.2	[5]	$ 9.0	[6]	$ 63.9	[7]	$ (162.6)		$ 146.1		$ 131.0
Earnings (loss) per share
Basic (in dollars per share)	$ (1.29)	[1],[9]	$ (1.13)	[2],[9]	$ 0.44	[9]	$ 0.78	[9]	$ (0.14)	[4],[10]	$ 0.68	[5],[10]	$ 0.07	[6],[10]	$ 0.47	[7],[10]	$ (1.19)		$ 1.07		$ 0.95
Diluted (in dollars per share)	$ (1.29)	[1],[9]	$ (1.13)	[2],[9]	$ 0.44	[9]	$ 0.77	[9]	$ (0.14)	[4],[10]	$ 0.67	[5],[10]	$ 0.07	[6],[10]	$ 0.47	[7],[10]	$ (1.19)		$ 1.07		$ 0.95
Weighted-average shares outstanding:
Basic (in shares)	135.4	[1]	136.5	[2]	136.4		136.2		136.1	[4]	136.0	[5]	136.0	[6]	135.9	[7]	136.1		136.0		137.8
Diluted (in shares)	135.4	[1]	136.5	[2]	137.5		137.3		137.0	[4]	136.8	[5]	136.5	[6]	136.2	[7]	136.1		136.5		138.3
Selected Quarterly Financial Information [Abstract]
Gain (loss) on sale of business											$ 71.7						$ (20.9)		$ 71.7		$ 0.0
Impairment charges	$ 144.4		$ 202.4						$ 141.6		10.9		$ 27.8				346.8		184.5		224.4
Change in financial assets	$ 122.3		(22.2)												$ 10.4
Loss on extinguishment of debt			$ 20.0														20.0		0.2		0.5
Restructuring													$ 12.2				$ 3.5		$ 26.3		$ 21.0
Impairment of intangible assets, indefinite-lived											18.1
Ranitidine
Selected Quarterly Financial Information [Abstract]
Production Related Impairments or Charges											$ 18.4

[1] Includes change in financial assets of $122.3 million and impairment charges of $144.4 million.

[2] Includes impairment charges of $202.4 million, change in financial assets of $22.2 million and loss on early debt extinguishment of $20.0 million.

[3] Includes Rosemont Pharmaceuticals business pre-tax loss of $21.1 million.

[4] Includes impairment charges of $141.6 million.

[5] Includes animal health divestiture pre-tax gain of $71.7 million, Ranitidine market withdrawal charges of $18.4 million, acquisition-related charges and contingent consideration adjustments of $18.1 million, and impairment charges of $10.9 million.

[6] Includes impairment charges of $27.8 million and restructuring charges and other termination benefits of $12.2 million.

[7] Includes change in financial assets of $10.4 million.

[8] The net sales by geography is derived from the location of the entity that sells to a third party.

[9] The sum of individual per share amounts may not equal due to rounding.

[10] The sum of individual per share amounts may not equal due to rounding.