Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	6 Months Ended			12 Months Ended
	Dec. 30, 2022		Jun. 16, 2022	Dec. 31, 2021		Dec. 25, 2020
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
Cost of sales	991.0		582.0	1,317.1		1,544.0
Gross profit	48.7		292.6	891.7		669.4
Selling, general and administrative expenses	290.1		275.3	581.8		884.1
Research and development expenses	64.2		65.5	205.2		290.8
Restructuring charges, net	11.1		9.6	26.9		37.5
Non-restructuring impairment charges	0.0		0.0	154.9		63.5
Losses (gains) on divestiture	0.0		0.0	0.8		(16.6)
Opioid-related litigation settlement loss (gain)	0.0		0.0	125.0		(43.4)
Medicaid lawsuit charge						(536.0)
Operating loss	(316.7)		(57.8)	(202.9)		(651.6)
Interest expense	(324.3)		(108.6)	(222.6)		(261.1)
Interest income	3.9		0.6	1.9		5.9
Other income (expense), net	10.0		(14.6)	22.0		7.4
Reorganization items, net	(23.2)		(630.9)	(428.2)		(61.4)
Loss from continuing operations before income taxes	(650.3)		(811.3)	(829.8)		(960.8)
(Benefit) expense from income taxes	(52.0)		(497.3)	(106.3)		8.9
Loss from continuing operations	(598.3)		(314.0)	(723.5)		(969.7)
Income from discontinued operations, net of tax benefit of $—, $—, $(5.0) and $(16.2)	0.2		0.9	6.1		25.1
Net loss	$ (598.1)		$ (313.1)	$ (717.4)		$ (944.6)
Loss from continuing operations	$ (45.43)		$ (3.70)	$ (8.54)		$ (11.48)
Income from discontinued operations	0.02		0.01	0.07		0.30
Earnings Per Share, Basic	$ (45.41)		$ (3.69)	$ (8.47)		$ (11.18)
Basic weighted-average shares outstanding	13.2		84.8	84.7		84.5
Loss from continuing operations	$ (45.43)		$ (3.70)	$ (8.54)		$ (11.48)
Income from discontinued operations	0.02		0.01	0.07		0.30
Earnings Per Share, Diluted	$ (45.41)		$ (3.69)	$ (8.47)		$ (11.18)
Weighted Average Number of Shares Outstanding, Diluted	13.2		84.8	84.7		84.5
Basic loss per share (Note 9):
Loss from continuing operations	$ (45.43)		$ (3.70)	$ (8.54)		$ (11.48)
Income from discontinued operations	$ 0.02		$ 0.01	$ 0.07		$ 0.30
Basic weighted-average shares outstanding	13.2		84.8	84.7		84.5
Diluted loss per share (Note 9):
Loss from continuing operations	$ (45.43)		$ (3.70)	$ (8.54)		$ (11.48)
Income from discontinued operations	0.02		0.01	0.07		0.30
Net loss	$ (45.41)		$ (3.69)	$ (8.47)		$ (11.18)
Diluted weighted-average shares outstanding	13.2		84.8	84.7		84.5
Supplemental Income Statement Elements [Abstract]
Discontinued Operation, Tax Effect of Discontinued Operation	$ 0.0		$ 0.0	$ (5.0)		$ (16.2)
Operating Expense [Member]
Medicaid lawsuit charge	0.0		0.0	0.0		(105.1)
Sales [Member]
Medicaid lawsuit charge	$ 0.0	[1]	$ 0.0	$ 0.0	[1]	$ (536.0)	[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).