Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions			3 Months Ended					6 Months Ended
		Jun. 26, 2020	Jun. 26, 2020		Jun. 14, 2020	Jun. 28, 2019		Jun. 26, 2020		Jun. 14, 2020	Jun. 28, 2019
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)			$ 166.5			$ 823.3		$ 832.3			$ 1,613.9
Medicaid lawsuit (Note 11)			639.7
Sales [Member]
Segment Reporting Information
Medicaid lawsuit (Note 11)			534.4	[1],[2]		0.0		534.4	[1],[2]		0.0
Medicaid Lawsuit [Member]
Segment Reporting Information
Decrease in revenue		$ 8.6			$ 12.3					$ 27.6
Medicaid Lawsuit [Member] | Sales Channel, Through Intermediary [Member]
Segment Reporting Information
Decrease in revenue		$ 6.8
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)			700.9			823.3		1,366.7			1,613.9
Operating Segments | 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)			178.1			195.5		353.3			381.9
Operating Segments | 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)			522.8	[2]		627.8		1,013.4	[2]		1,232.0
Corporate, Non-Segment
Segment Reporting Information
Medicaid lawsuit (Note 11)			(639.7)	[2]		0.0		(639.7)	[2]		0.0
Acthar | Operating Segments | 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)			213.7	[3]		266.4		381.3	[3]		490.3
Inomax | Operating Segments | 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)			154.9			139.7		296.6			290.8
Ofirmev | Operating Segments | 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)			52.4			90.5		127.3			186.1
Therakos immunotherapy | Operating Segments | 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)			47.8			60.9		111.5			122.7
Amitiza [Member] | Operating Segments | 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]		49.4			52.0		90.5			105.0
BioVectra Inc [Member] | Operating Segments | 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)						13.9					26.3
Other | Operating Segments | 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)			4.4			10.8		8.5			22.9
Other | Operating Segments | 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)			4.6			18.3	[5]	6.2			37.1	[5]
Hydrocodone (API) [Member] | Operating Segments | 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)			25.4			18.1		51.9			35.5
Oxycodone (API) [Member] | Operating Segments | 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)			15.0			19.6		31.9			36.1
Acetaminophen (API) [Member] | Operating Segments | 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)			55.5			48.4		99.6			94.6
Other Controlled Substances [Member] | Operating Segments | 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)			$ 77.8			$ 98.6		$ 161.4			$ 192.8

[1] Of this amount, $12.3 million and $27.6 million represent the impact of the Medicaid rebate calculation through June 14, 2020 for the three and six months ended June 26, 2020, respectively.

[2] Specialty Brands net sales for the three and six months ended June 26, 2020 includes the prospective change to the Medicaid rebate calculation, which served to reduce Acthar Gel net sales by $8.6 million for the period from June 15, 2020 through June 26, 2020, of which $6.8 million represents the channel impact. Of the $534.4 million recorded as a component of net sales, $12.3 million and $27.6 million represent the impact of the Medicaid rebate calculation through June 14, 2020 for the three and six months ended June 26, 2020, respectively. See Note 11 for further detail on the status of the Medicaid lawsuit.

[3] The three and six months ended June 26, 2020 includes the prospective change to the Medicaid rebate calculation of $8.6 million for the period from June 15, 2020 through June 26, 2020, of which $6.8 million represents the channel impact. See Note 11 for further detail on the status of the Medicaid lawsuit.

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

[5] The three and six months ended June 28, 2019 includes $13.9 million and $26.3 million of net sales, respectively, related to BioVectra prior to the completion of the sale of this business in November 2019.