Bankruptcy (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 16, 2022	Oct. 12, 2020	Sep. 30, 2022	Dec. 30, 2022	Jun. 16, 2022	Dec. 31, 2021	Dec. 25, 2020
Reorganizations [Line Items]
Restructuring Support Agreement, Common Stock Share Percentage Reorganized New Company	100.00%				100.00%
Cash paid for interest				$ 164.1	$ 111.5	$ 243.2	$ 256.1
Accrued interest				29.0		17.0
Interest Protection Payment, Expense					$ 28.8	63.1	11.7
Debt instrument, face amount				3,534.1
Class of Warrant or Right, Outstanding	3,290,675				3,290,675
Opioid Warrants, Par value	$ 0.01				$ 0.01
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 103.40				$ 103.40
Acthar Gel-Related Settlement, Current	$ 260.0				$ 260.0
Acthar Gel-Related Settlement, Term	7 years				7 years
Acthar Gel-Related Settlement, Upfront Payment	$ 15.0				$ 15.0
Acthar Gel-Related Settlement, Payment Year One	15.0				15.0
Acthar Gel-Related Settlement, Payment Year Two and Three	20.0				20.0
Acthar Gel-Related Settlement, Payment Year Six and Seven	62.5				62.5
Settlement of General Unsecured Claims	135.0				135.0
Payments for Repurchase of Warrants				4.0
Issuance of external debt	650.0			0.0	650.0	0.0	0.0
Acthar Gel-Related Settlement, Payment Year Four and Five	32.5				32.5
StrataGraft PRV
Reorganizations [Line Items]
Other Indefinite-lived Intangible Assets	100.0				100.0
StrataGraft PRV | Mallinckrodt
Reorganizations [Line Items]
Proceeds from Sale of Intangible Assets			$ 65.0	65.0
StrataGraft PRV | General Unsecured Claims Trust
Reorganizations [Line Items]
Proceeds from Sale of Intangible Assets			$ 35.0	35.0
Terlipressin Contingent Consideration
Reorganizations [Line Items]
Contingent consideration	20.0				20.0
Terlipressin Contingent Consideration | Terlipressin [Member]
Reorganizations [Line Items]
Revenue from Customer, Cumulative Threshold	100.0				100.0
Reorganization, Chapter 11, Plan Effect Adjustment
Reorganizations [Line Items]
Accrued interest	(13.0)				(13.0)
Acthar Gel-Related Settlement, Current	16.5				16.5
Payment for Debt Extinguishment or Debt Prepayment Cost	(900.0)
Contingent consideration	$ (41.8)				$ (41.8)
Ordinary shares, shares issued (in shares)	13,170,932				13,170,932
Reorganization, Chapter 11, Plan Effect Adjustment | StrataGraft PRV | General Unsecured Claims Trust
Reorganizations [Line Items]
Contingent consideration	$ 35.0				$ 35.0
Secured Debt
Reorganizations [Line Items]
Restructuring Support Agreement, Proposed Long-Term Debt	$ 375.0				375.0
Debt Instrument, Interest Rate, Increase (Decrease)		200.00%
Interest Protection Payment, Paid					$ 28.8	66.7	7.8
Term Loans due Sept 2024 and Feb 2025 [Member]
Reorganizations [Line Items]
Debt Instrument, Interest Rate, Increase (Decrease)		250.00%
5.75% senior notes due August 2022
Reorganizations [Line Items]
Debt instrument, face amount				0.0
5.75% senior notes due August 2022 | Senior Notes
Reorganizations [Line Items]
Stated interest rate	5.75%				5.75%
5.75% senior notes due August 2022 | Senior Notes | Fair Value, Inputs, Level 1 [Member]
Reorganizations [Line Items]
Stated interest rate	5.75%				5.75%
Five Point Six Two Five Percent Note
Reorganizations [Line Items]
Debt instrument, face amount				0.0
Five Point Six Two Five Percent Note | Debentures
Reorganizations [Line Items]
Stated interest rate	5.625%				5.625%
Five Point Six Two Five Percent Note | Debentures | Fair Value, Inputs, Level 1 [Member]
Reorganizations [Line Items]
Stated interest rate	5.625%				5.625%
Five Point Five Percent Notes [Member]
Reorganizations [Line Items]
Debt instrument, face amount				0.0
Five Point Five Percent Notes [Member] | Senior Notes
Reorganizations [Line Items]
Stated interest rate	5.50%				5.50%
Five Point Five Percent Notes [Member] | Senior Notes | Fair Value, Inputs, Level 1 [Member]
Reorganizations [Line Items]
Stated interest rate	5.50%				5.50%
9.50% debentures due May 2022
Reorganizations [Line Items]
Debt instrument, face amount				0.0
9.50% debentures due May 2022 | Debentures
Reorganizations [Line Items]
Stated interest rate	9.50%				9.50%
8.00% debentures due March 2023
Reorganizations [Line Items]
Debt instrument, face amount				0.0
8.00% debentures due March 2023 | Debentures
Reorganizations [Line Items]
Stated interest rate	8.00%				8.00%
4.75% senior notes due April 2023
Reorganizations [Line Items]
Debt instrument, face amount				0.0
4.75% senior notes due April 2023 | Senior Notes
Reorganizations [Line Items]
Stated interest rate	4.75%				4.75%
4.75% senior notes due April 2023 | Senior Notes | Fair Value, Inputs, Level 1 [Member]
Reorganizations [Line Items]
Stated interest rate	4.75%				4.75%
Debentures
Reorganizations [Line Items]
Increase (Decrease) in Interest Payable, Net					$ 46.5	$ 93.0	$ 28.8
Term Loan and New Term Loan
Reorganizations [Line Items]
Debt instrument, face amount				0.0
Term Loan due 2025 [Member]
Reorganizations [Line Items]
Debt instrument, face amount				0.0
2017 Replacement Term Loan
Reorganizations [Line Items]
Debt instrument, face amount	$ 1,392.9			1,374.1	1,392.9
2017 Replacement Term Loan | Reorganization, Chapter 11, Plan Effect Adjustment
Reorganizations [Line Items]
Debt instrument, face amount	1,392.9				1,392.9
2018 Replacement Term Loan
Reorganizations [Line Items]
Debt instrument, face amount	369.7			364.8	369.7
2018 Replacement Term Loan | Reorganization, Chapter 11, Plan Effect Adjustment
Reorganizations [Line Items]
Debt instrument, face amount	369.7				$ 369.7
2017 Revolving Credit Facility
Reorganizations [Line Items]
Debt instrument, face amount				0.0
2017 Revolving Credit Facility | Reorganization, Chapter 11, Plan Effect Adjustment
Reorganizations [Line Items]
Payment for Debt Extinguishment or Debt Prepayment Cost	$ 900.0
Ten Point Zero Percent First Lien Notes [Member]
Reorganizations [Line Items]
Stated interest rate	10.00%				10.00%
Debt instrument, face amount	$ 495.0			495.0	$ 495.0
Ten Point Zero Percent Second Lien Notes (Existing Notes)
Reorganizations [Line Items]
Debt instrument, face amount	$ 322.9			0.0	$ 322.9
Ten Point Zero Percent Second Lien Notes (New 2L Notes)
Reorganizations [Line Items]
Stated interest rate	10.00%				10.00%
Debt instrument, face amount	$ 322.9			321.9	$ 322.9
Ten Point Zero Percent Second Lien Notes (New 2L Notes) | Senior Notes
Reorganizations [Line Items]
Stated interest rate	10.00%				10.00%
Ten Point Zero Percent Second Lien Notes (New 2L Notes) | Senior Notes | Fair Value, Inputs, Level 1 [Member]
Reorganizations [Line Items]
Stated interest rate	10.00%				10.00%
Eleven Point Five Percent First Lien Senior Secured Notes
Reorganizations [Line Items]
Stated interest rate	11.50%				11.50%
Debt instrument, face amount				650.0
Eleven Point Five Percent First Lien Senior Secured Notes | Senior Notes
Reorganizations [Line Items]
Stated interest rate	11.50%				11.50%
Receivables Financing Facility
Reorganizations [Line Items]
Debt instrument, face amount	$ 200.0				$ 200.0
Maximum
Reorganizations [Line Items]
Remedial cost, estimate				$ 48.5
Opioid Claimant Trust [Member]
Reorganizations [Line Items]
Opioid-related Settlement	1,725.0				1,725.0
Opioid-Related Settlement, Upfront Payment	2.6				2.6
Opioid-Related Settlement, Payment Year One and Two	200.0				200.0
Opioid-Related Settlement, Year Eight	125.0
Opioid-Related Settlement, Year Three through Seven	150.0
Opioid-Related Settlement, Upfront Payment, Prefunded Amount	450.0				450.0
Opioid Claimant Trust [Member] | Reorganization, Chapter 11, Plan Effect Adjustment
Reorganizations [Line Items]
Opioid-related Settlement	$ 1,725.0				$ 1,725.0
Opioid Claimant Trust [Member] | Ownership Interest [Member]
Reorganizations [Line Items]
Opioid-Related Settlement, Warrants Common Stock Share Percentage Reorganized New Company	19.99%				19.99%
Medicaid Lawsuit [Member] | Maximum
Reorganizations [Line Items]
Remedial cost, estimate	$ 640.0				$ 640.0