Segment Data (Schedule of Segment Reporting Information by Business Segment) (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
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
Operating Income (Loss)			(725.5)			(29.9)	(731.8)			(14.5)
Intangible asset amortization			(191.6)			(216.6)	(389.2)			(439.4)
Opioid-related litigation settlement (Note 11)			8.5			0.0	(8.3)			0.0
Non-restructuring impairment charges			(63.5)			(113.5)	(63.5)			(113.5)
Medicaid lawsuit charge			(639.7)
Sales [Member]
Medicaid lawsuit charge			(534.4)	[1],[2]		0.0	(534.4)	[1],[2]		0.0
Medicaid Lawsuit [Member]
Decrease in revenue		$ 8.6			$ 12.3				$ 27.6
Medicaid Lawsuit [Member] | Sales Channel, Through Intermediary [Member]
Decrease in revenue		$ 6.8
Specialty Brands
Restructuring and related charges, net			(0.1)			0.1	(0.1)			(0.4)
Specialty Generics
Restructuring and related charges, net			0.0			0.9	(0.1)			(2.6)
Operating Segments
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 Income (Loss)			280.0			355.3	540.5			655.2
Operating Segments | Specialty Brands
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
Operating Income (Loss)			245.1			321.4	457.3			596.9
Operating Segments | Specialty Generics
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 Income (Loss)			34.9			33.9	83.2			58.3
Corporate, Non-Segment
Corporate and unallocated expenses	[3]		(62.1)			(36.4)	(128.6)			(82.2)
Intangible asset amortization			(191.6)			(216.6)	(389.2)			(439.4)
Restructuring and related charges, net			(14.4)			0.2	(12.6)			(4.0)
Separation Costs	[4]		(20.7)			(18.9)	(42.0)			(30.6)
Opioid-related litigation settlement (Note 11)			(8.5)	[5]		0.0	8.3	[5]		0.0
R&D Upfront Payment			(5.0)	[6]		0.0	(5.0)	[6]		0.0
Medicaid lawsuit charge			$ 639.7	[2]		$ 0.0	$ 639.7	[2]		$ 0.0

[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] Includes administration expenses and certain compensation, legal, environmental and other costs not charged to the Company's reportable segments.

[4] These costs, which are included in SG&A expenses, primarily relate to professional fees, incremental costs incurred to build out the corporate infrastructure of the previously planned spin-off of the Company's Specialty Generics segment, costs incurred as the Company works to resolve opioid uncertainties, as well as rebranding initiatives associated with the Specialty Brands ongoing transformation.

[5] Represents the change in the Settlement Warrants' fair value. Refer to Note 12 for further information regarding the valuations of the Settlement Warrants.

[6] Represents R&D expense incurred related to an upfront payment made to acquire product rights in Japan for terlipressin.