Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 26, 2021		Mar. 27, 2020
Segment Reporting Information
Net sales		$ 558.0		$ 665.8
Medicaid Lawsuit [Member]
Segment Reporting Information
Decrease in revenue		12.5
Specialty Generics
Segment Reporting Information
Net sales		149.6		175.2
Specialty Brands
Segment Reporting Information
Net sales		408.4		490.6
Acthar | Specialty Brands
Segment Reporting Information
Net sales		129.0	[1]	167.6
Inomax | Specialty Brands
Segment Reporting Information
Net sales		134.0		141.7
Ofirmev | Specialty Brands
Segment Reporting Information
Net sales		12.8		74.9
Therakos immunotherapy | Specialty Brands
Segment Reporting Information
Net sales		66.8		63.7
Amitiza [Member] | Specialty Brands
Segment Reporting Information
Net sales	[2]	61.4		41.1
Other | Specialty Generics
Segment Reporting Information
Net sales		5.5		4.1
Other | Specialty Brands
Segment Reporting Information
Net sales		4.4		1.6
Hydrocodone (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales		23.3		26.5
Oxycodone (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales		17.2		16.9
Acetaminophen (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales		45.5		44.1
Other Controlled Substances [Member] | Specialty Generics
Segment Reporting Information
Net sales		$ 58.1		$ 83.6

[1] The three months ended March 26, 2021 includes the prospective change to the Medicaid rebate calculation that began in June 2020, which impacted Acthar Gel net sales by $12.5 million. See Note 11 for further detail on the status of the Medicaid lawsuit.

[2] Amitiza consists of both product net sales and royalties. Refer to Note 2 for further details on Amitiza's revenues.