Segment and Geographical Data (Schedule of Segment Reporting Information by Business Segment) (Details) - USD ($) $ in Millions	6 Months Ended			12 Months Ended
	Dec. 30, 2022		Jun. 16, 2022	Dec. 31, 2021		Dec. 25, 2020
Segment Reporting Information [Line Items]
Net sales (includes retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	$ 1,039.7		$ 874.6	$ 2,208.8		$ 2,213.4
Operating income (loss)	(316.7)		(57.8)	(202.9)		(651.6)
Intangible asset amortization	(318.7)		(281.8)	(581.1)		(771.2)
Restructuring and related charges, net	(12.1)		(9.6)	(29.0)		(49.8)
Other Asset Impairment Charges	0.0		0.0	(154.9)		(63.5)
Opioid-related litigation settlement loss (gain)	0.0		0.0	125.0		(43.4)
Depreciation and amortization	347.5		321.8	675.8		885.2
Restructuring and related costs, accelerated depreciation	1.0		0.0	2.1		12.3
Medicaid lawsuit						536.0
Employee Benefits and Share-based Compensation	(1.4)		(1.7)	(10.2)		(25.3)
Petition Amount Filed with Bankruptcy Court
Segment Reporting Information [Line Items]
Bad Debt Expense, Customer Bankruptcy, Pre-Petition Amount	(6.4)		0.0	0.0		0.0
Medicaid Lawsuit [Member]
Segment Reporting Information [Line Items]
Decrease in revenue	40.4
Sales [Member]
Segment Reporting Information [Line Items]
Medicaid lawsuit	0.0	[1]	0.0	0.0	[1]	536.0	[1]
Specialty Brands [Member]
Segment Reporting Information [Line Items]
Restructuring and related charges, net	0.0		0.0	(0.1)		(0.1)
Specialty Generics [Member]
Segment Reporting Information [Line Items]
Restructuring and related charges, net	(0.8)		(3.5)	(4.9)		(0.1)
Operating Segments
Segment Reporting Information [Line Items]
Net sales (includes retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	1,039.7		874.6	2,208.8		2,749.4
Operating income (loss)	110.2		332.5	920.7		1,222.1
Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales (includes retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	682.4	[1]	587.1	1,547.0	[1]	2,059.6	[1]
Operating income (loss)	113.8		267.2	812.8		1,015.7
Depreciation and amortization	323.6		288.4	597.7		799.3
Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales (includes retrospective one-time charge of $536.0 related to the Medicaid lawsuit for fiscal 2020)	357.3		287.5	661.8		689.8
Operating income (loss)	(3.6)		65.3	107.9		206.4
Depreciation and amortization	23.9		33.4	78.1		85.9
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Corporate and allocated expenses	(39.3)	[2]	(48.2)	(129.6)	[2]	(166.1)	[2]
Intangible asset amortization	(347.5)		(321.8)	(675.8)		(885.2)
Restructuring and related charges, net	(11.1)		(9.6)	(26.9)		(37.5)
Other Asset Impairment Charges	0.0		0.0	(154.9)		(63.5)
Separation costs	21.2	[3]	9.0	1.2	[3]	93.4	[3]
R&D upfront payment	0.0	[4]	0.0	0.0	[4]	(5.0)	[4]
Opioid-related litigation settlement loss (gain)	0.0		0.0	(125.0)		43.4
Medicaid lawsuit	$ 0.0	[1]	$ 0.0	$ 0.0	[1]	$ (641.1)

[1] Specialty Brands net sales for fiscal 2020 (Predecessor) includes the prospective change to the Medicaid rebate calculation, which served to reduce Acthar Gel net sales by $40.4 million for the period from June 15, 2020 through December 25, 2020 (Predecessor).

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

[3] Represents costs included in SG&A expenses, primarily related to expenses incurred related to the severance for the former CEO and certain former executives of the Predecessor, in addition to professional fees and costs incurred as the Company explores potential sales of non-core assets to enable further deleveraging post-emergence from bankruptcy during the period from June 17, 2022 through December 30, 2022 (Successor). Costs incurred during the Predecessor periods include professional fees and costs incurred in preparation for the Chapter 11 proceedings. As of the Petition Date, professional fees directly related to the Chapter 11 proceedings that were previously reflected as separation costs were classified on a go-forward basis as reorganization items, net.

[4] Represents R&D expense incurred related to an upfront payment made to acquire product rights in Japan for Terlivaz during fiscal 2020.