Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 28, 2019	Jun. 29, 2018	Jun. 28, 2019	Jun. 29, 2018
Segment Reporting Information
Net sales		$ 823.3	$ 825.5	$ 1,613.9	$ 1,580.8
Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		627.8	631.7	1,232.0	1,204.3
Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		195.5	193.8	381.9	376.5
Acthar | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		266.4	293.2	490.3	537.0
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		139.7	131.0	290.8	270.8
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		90.5	85.6	186.1	167.6
Therakos immunotherapy | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		60.9	56.8	122.7	114.2
Amitiza [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales	[1]	52.0	48.0	105.0	71.0
BioVectra Inc [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		13.9	11.3	26.3	21.8
Other | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales		4.4	5.8	10.8	21.9
Other | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		10.8	12.6	22.9	26.4
Hydrocodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		18.1	16.9	35.5	30.8
Oxycodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		19.6	13.1	36.1	29.7
Acetaminophen (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		48.4	51.7	94.6	101.1
Other Controlled Substances [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales		$ 98.6	$ 99.5	$ 192.8	$ 188.5

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