Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 25, 2021	Jun. 26, 2020	Jun. 25, 2021	Jun. 26, 2020
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		$ 546.4	$ 166.5	$ 1,104.4	$ 832.3
Operating Segments
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		546.4	700.9	1,104.4	1,366.7
Specialty Generics | Operating Segments
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		164.9	178.1	314.5	353.3
Specialty Brands | Operating Segments
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		381.5	522.8	789.9	1,013.4
Acthar | Specialty Brands
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		151.5	213.7	280.5	381.3
Inomax | Specialty Brands
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		105.9	154.9	239.9	296.6
Ofirmev | Specialty Brands
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		6.5	52.4	19.3	127.3
Therakos immunotherapy | Specialty Brands
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		68.5	47.8	135.3	111.5
Amitiza [Member] | Specialty Brands
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)	[1]	44.8	49.4	106.2	90.5
Other | Specialty Generics
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		6.6	4.4	12.1	8.5
Other | Specialty Brands
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		4.3	4.6	8.7	6.2
Hydrocodone (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		20.5	25.4	43.8	51.9
Oxycodone (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		17.1	15.0	34.3	31.9
Acetaminophen (API) [Member] | Specialty Generics
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		51.7	55.5	97.2	99.6
Other Controlled Substances [Member] | Specialty Generics
Segment Reporting Information
Net sales (includes retrospective one-time charge of $534.4 million related to the Medicaid lawsuit for the three and six months ended June 26, 2020)		$ 69.0	$ 77.8	$ 127.1	$ 161.4

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