Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 01, 2022	Mar. 26, 2021
Segment Reporting Information
Net sales		$ 490.9	$ 558.0
Specialty Brands | Operating Segments
Segment Reporting Information
Net sales		339.4	408.4
Specialty Generics | Operating Segments
Segment Reporting Information
Net sales		151.5	149.6
Acthar | Specialty Brands
Segment Reporting Information
Net sales		127.7	129.0
Inomax | Specialty Brands
Segment Reporting Information
Net sales		99.0	134.0
Ofirmev | Specialty Brands
Segment Reporting Information
Net sales		2.6	12.8
Therakos immunotherapy | Specialty Brands
Segment Reporting Information
Net sales		59.9	66.8
Amitiza [Member] | Specialty Brands
Segment Reporting Information
Net sales	[1]	47.7	61.4
Other | Specialty Brands
Segment Reporting Information
Net sales		2.5	4.4
Other | Specialty Generics
Segment Reporting Information
Net sales		5.5	5.5
Hydrocodone (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales		19.0	23.3
Oxycodone (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales		16.6	17.2
Acetaminophen (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales		46.3	45.5
Other Controlled Substances [Member] | Specialty Generics
Segment Reporting Information
Net sales		$ 64.1	$ 58.1

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