Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 27, 2020	Mar. 29, 2019
Segment Reporting Information
Net sales		$ 665.8	$ 790.6
Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		175.2	186.4
Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		490.6	604.2
Acthar | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		167.6	223.9
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		141.7	151.1
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		74.9	95.6
Therakos immunotherapy | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		63.7	61.8
Amitiza [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	[1]	41.1	53.0
BioVectra Inc [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales			12.4
Other | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		4.1	12.1
Other | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	[2]	1.6	18.8
Hydrocodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		26.5	17.4
Oxycodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		16.9	16.5
Acetaminophen (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		44.1	46.2
Other Controlled Substances [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		$ 83.6	$ 94.2

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

[2] The three months ended March 29, 2019 includes $12.4 million of net sales related to BioVectra prior to the completion of the sale of this business in November 2019.