Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 25, 2020		Sep. 27, 2019		Sep. 25, 2020		Sep. 27, 2019
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		$ 698.3		$ 743.7		$ 1,530.6		$ 2,357.6
Medicaid lawsuit (Note 11)						640.2
Sales [Member]
Segment Reporting Information
Medicaid lawsuit (Note 11)		0.7		0.0		535.1		0.0
Medicaid Lawsuit [Member]
Segment Reporting Information
Decrease in revenue		22.2				30.8
Operating Segments
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		699.0		743.7		2,065.7		2,357.6
Operating Segments | Specialty Generics
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		159.4		163.3		512.7		545.2
Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		539.6		580.4		1,553.0		1,812.4
Corporate, Non-Segment
Segment Reporting Information
Medicaid lawsuit (Note 11)		(0.5)		0.0		(640.2)		0.0
Acthar | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		195.3	[1]	229.8		576.6	[1]	720.1
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		141.9		136.8		438.5		427.6
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		88.7		86.1		216.0		272.2
Therakos immunotherapy | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		62.6		60.9		174.1		183.6
Amitiza [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)	[2]	47.7		52.6		138.2		157.6
BioVectra Inc [Member] | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)				10.5				36.8
Other | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		6.0		9.0		14.5		31.9
Other | Operating Segments | Specialty Brands
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		3.4		14.2	[3]	9.6		51.3	[3]
Hydrocodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		20.0		15.7		71.9		51.2
Oxycodone (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		16.1		17.2		48.0		53.3
Acetaminophen (API) [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		54.9		48.5		154.5		143.1
Other Controlled Substances [Member] | Operating Segments | Specialty Generics
Segment Reporting Information
Net sales (includes refined estimate of the retrospective one-time charge of $0.7 and $535.1 related to the Medicaid lawsuit for the three and nine months ended September 25, 2020, respectively)		$ 62.4		$ 72.9		$ 223.8		$ 265.7

[1] The three and nine months ended September 25, 2020 includes the prospective change to the Medicaid rebate calculation beginning in June 2020, which impacted Acthar Gel net sales by $22.2 million and $30.8 million, respectively. See Note 11 for further detail on the status of the Medicaid lawsuit.

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

[3] The three and nine months ended September 27, 2019 includes $10.5 million and $36.8 million of net sales, respectively, related to BioVectra prior to the completion of the sale of this business in November 2019.