Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 27, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018
Segment Reporting Information
Net sales		$ 743.7	$ 799.9	$ 2,357.6	$ 2,380.7
Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		580.4	640.0	1,812.4	1,844.3
Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		163.3	159.9	545.2	536.4
Acthar | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		229.8	290.1	720.1	827.1
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		136.8	133.2	427.6	404.0
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		86.1	87.1	272.2	254.7
Therakos immunotherapy | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		60.9	60.0	183.6	174.2
Amitiza [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	[1]	52.6	48.2	157.6	119.2
BioVectra Inc [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		10.5	13.9	36.8	35.7
Other | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		3.7	7.5	14.5	29.4
Other | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		9.0	13.4	31.9	39.8
Hydrocodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		15.7	15.5	51.2	46.3
Oxycodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		17.2	13.6	53.3	43.3
Acetaminophen (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		48.5	47.9	143.1	149.0
Other Controlled Substances [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		$ 72.9	$ 69.5	$ 265.7	$ 258.0

[1] Amitiza consists of both product net sales and royalties. Refer to Note 3 for further details on Amitiza's revenues.