Reorganizations (Details) $ in Millions			3 Months Ended			6 Months Ended	9 Months Ended
		Aug. 23, 2023 USD ($)	Sep. 29, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 16, 2022 USD ($)	Sep. 29, 2023 USD ($)	Aug. 24, 2023 USD ($)	Jun. 16, 2023 USD ($)	Dec. 30, 2022 USD ($)
Reorganizations [Abstract]
Non-Debtor Intercompany Payables to Debtor Entities			$ 190.7				$ 190.7
Liabilities subject to compromise			4,932.1				4,932.1			$ 0.0
Reorganization, Chapter 11 [Line Items]
Liabilities subject to compromise			4,932.1				4,932.1			0.0
Gain on settlements of liabilities subject to compromise				$ 0.0		$ (943.7)	0.0
Reorganization Items, net, Loss on Fresh-Start Adjustments				0.0		1,354.6	0.0
Debtor Reorganization Items, Legal and Advisory Professional Fees			17.4	17.7	$ 14.2	161.1	27.0
Debtor Reorganization Items, Success Fees				0.0		44.3	0.0
Debtor Reorganization Items, Net, Prepaid Expense Write-Off				0.0		9.2	0.0
Debtor Reorganization Items, Debt Valuation Adjustments and Write-off of Debt Issuance Costs and Debt Discounts			426.9	0.0	0.0	0.0	426.9
Debtor Reorganization Items, Gain (Loss) on Settlement of Other Claims, Net			867.2	0.0	0.0	5.4	867.2
Reorganization items, net			1,311.5	$ 17.7	$ 14.2	630.9	1,321.1
Cash Paid, Reorganization items			2.1			$ 304.1
Reorganization Items. Makewhole Claim, 2025 First Lien Secnior Secured Notes		$ 14.9
Opioid-Related Litigation Settlement, Payment Year Two									$ 200.0
Opioid-Related Litigation Settlement, Final Payment								$ 250.0
2023 Restructuring Support Agreement, Trust Contingent Value Rights, Share Percentage of Reorganized New Company		5.00%
2023 Restructuring Support Agreement, Equity Value of Reorganized Debtors		$ 3,776.0
Reorganization Items, Makewhole Claim, 2028 First Lien Senior Secured Notes		108.9
Debt Instrument, Face Amount										$ 3,534.1
Non-Debtor Intercompany Receivables From Debtor Entities			25.9				25.9
Non-Debtor Intercompany Payables to Debtor Entities			190.7				190.7
Second Lien Funded Debt
Reorganization, Chapter 11 [Line Items]
Increase (Decrease) in Interest Payable, Net			40.6
Receivables Financing Facility
Reorganization, Chapter 11 [Line Items]
Debt Instrument, Face Amount			$ 100.0				$ 100.0
2023 Restructuring Support Agreement
Reorganization, Chapter 11 [Line Items]
Debtor-in-Possession Financing, Amount Arranged		250.0
Debt Instrument, Increase (Decrease), Net		2,861.8
Restructuring Support Agreement, Proposed Long-Term Debt		$ 1,650.0
2023 Restructuring Support Agreement | First Lien Claimholders
Reorganization, Chapter 11 [Line Items]
Restructuring Support Agreement, Equity Share Ownership of Reorganized New Company		92.30%
2023 Restructuring Support Agreement | Second Lien Claimholders
Reorganization, Chapter 11 [Line Items]
Restructuring Support Agreement, Equity Share Ownership of Reorganized New Company		7.70%
2023 Restructuring Support Agreement | Receivables Financing Facility
Reorganization, Chapter 11 [Line Items]
Debt Instrument, Face Amount		$ 200.0
First Lien Funded Debt | 2023 Restructuring Support Agreement
Reorganization, Chapter 11 [Line Items]
Holders of Principal Debt, Percentage		0.72
Second Lien Funded Debt | 2023 Restructuring Support Agreement
Reorganization, Chapter 11 [Line Items]
Holders of Principal Debt, Percentage		0.71
First and Second Lien Funded Debt | 2023 Restructuring Support Agreement
Reorganization, Chapter 11 [Line Items]
Holders of Principal Debt, Percentage			0.90				0.90
Interest Payable, Current
Reorganizations [Abstract]
Liabilities subject to compromise	[1]		$ 159.0				$ 159.0
Reorganization, Chapter 11 [Line Items]
Liabilities subject to compromise	[1]		159.0				159.0
Long-term Debt
Reorganizations [Abstract]
Liabilities subject to compromise	[2]		3,512.0				3,512.0
Reorganization, Chapter 11 [Line Items]
Liabilities subject to compromise	[2]		3,512.0				3,512.0
Debtor Reorganization Items, Provision for Expected Allowed Claims			377.6
Acthar Gel-Related Settlement
Reorganizations [Abstract]
Liabilities subject to compromise	[3]		236.1				236.1
Reorganization, Chapter 11 [Line Items]
Liabilities subject to compromise	[3]		236.1				236.1
Debtor Reorganization Items, Provision for Expected Allowed Claims			145.0
Opioid-related litigation settlement liability
Reorganizations [Abstract]
Liabilities subject to compromise	[4]		1,025.0				1,025.0
Reorganization, Chapter 11 [Line Items]
Liabilities subject to compromise	[4]		1,025.0				$ 1,025.0
Debtor Reorganization Items, Provision for Expected Allowed Claims			$ 598.4

[1] Accrued interest includes $14.9 million and $108.9 million related to makewhole settlement allowed claims with the 2025 and 2028 first lien senior secured noteholders, respectively, prescribed for per the RSA and 2023 Plan.

[2] The Company expensed $377.6 million to adjust the carrying value up to the principal value or estimated allowed claim amount and recorded the expense within in reorganization items, net in the unaudited condensed consolidated statement of operations for the three months ended September 29, 2023 (Successor).

[3] The Company expensed $145.0 million as reorganization items, net to adjust the present value of the Acthar Gel-Related Settlement liability to its estimated allowed claim amount during the three months ended September 29, 2023 (Successor). This settlement obligation is listed as unimpaired in the 2023 Plan, but is classified as LSTC in accordance with ASC 852 given it is unsecured and its ultimate treatment is dependent upon the effectuation of the 2023 Plan.

[4] The Company expensed $598.4 million as reorganization items, net to adjust the present value of the Opioid-Related Litigation Settlement liability to its estimated allowed claim amount during the three months ended September 29, 2023 (Successor). This settlement obligation is classified as LSTC in accordance with ASC 852 given it is unsecured and its ultimate permanent elimination is dependent upon the effectuation of the 2023 Plan. Refer to Note 12 for further information.