Consolidated Statements of Cash Flows - USD ($) $ in Millions	1 Months Ended	6 Months Ended		11 Months Ended	12 Months Ended
	Dec. 29, 2023	Dec. 30, 2022	Jun. 16, 2022	Nov. 14, 2023	Dec. 27, 2024	Dec. 31, 2021
Restricted Cash and Investments, Current	$ 40.8	$ 20.6	$ 113.0	$ 47.0	$ 21.5
Restricted Cash and Investments, Noncurrent	39.9	36.6	36.4	39.7	41.6
Cash and cash equivalents	262.7	409.5	297.9	186.7	382.6
Cash and Cash Equivalents, Including Restricted Cash	343.4	466.7	447.3	273.4	445.7	$ 1,405.2
Effect of currency rate changes on cash	1.4	(1.1)	(3.9)	(1.7)	(2.5)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	70.0	19.4	(957.9)	(193.3)	102.3
Cash Flows from Operating Activities:
Net income (loss)	(38.2)	(598.1)	(313.1)	(1,631.3)	477.9
Adjustments to reconcile net cash from operating activities:
Depreciation and amortization	25.8	347.5	321.8	490.3	117.2
Share-based compensation	0.0	1.4	1.7	8.9	7.2
Deferred income taxes	(6.6)	(24.9)	(473.0)	(319.2)	158.1
Non-cash impairment charges	3.8	0.0	0.0	179.9	0.0
Gain on divestiture (Note 5)	0.0	0.0	0.0	0.0	(754.4)
Loss on debt extinguishment, net	0.0	0.0	0.0	0.0	19.7
Other non-cash items	6.7	16.8	35.3	14.2	18.8
Reorganization items, net	0.0	0.0	425.4	831.0	0.0
Accretion Expense	0.7	139.2	0.0	176.7	(4.3)
Changes in assets and liabilities:
Accounts receivable, net	88.6	(18.1)	49.8	(65.5)	(30.2)
Inventories	51.1	267.9	(33.2)	108.2	261.5
Accounts payable	25.8	8.1	(3.6)	(37.2)	(26.3)
Increase (Decrease) in Accrued Consulting	(6.8)	(90.7)	0.1	25.0	(20.8)
Income taxes	(1.7)	(30.1)	(26.9)	169.3	(46.0)
Opioid-Related Litigation Settlement liability	0.0	0.0	0.0	(250.0)	0.0
Increase (Decrease) Acthar Gel-Related Litigation Settlement	0.0	0.0	0.0	(16.5)	(21.4)
Payment of claims	0.0	0.0	(629.0)	0.0	0.0
Other	30.6	28.1	2.4	(95.9)	3.7
Net cash from operating activities	178.4	47.1	(642.3)	(412.1)	160.7
Cash Flows from Investing Activities:
Capital expenditures	(8.5)	(28.8)	(33.4)	(53.9)	(113.2)
Proceeds from divestiture, net of divested cash (Note 5)	0.0	70.0	0.0	0.0	876.2
Proceeds from Sale of Restricted Investments	0.0	0.0	0.0	0.0	22.6
Other	0.9	(13.7)	0.4	1.2	4.9
Net cash from investing activities	(7.6)	27.5	(33.0)	(52.7)	790.5
Cash Flows from Financing Activities:
Issuance of external debt	0.0	0.0	650.0	380.0	0.0
Repayment of external debt	(102.2)	(50.1)	(904.6)	(102.6)	(782.1)
Makewhole premium (Note 14)	0.0	0.0	0.0	0.0	(63.7)
Debt financing costs	0.0	0.0	(24.1)	(4.1)	0.0
Other	0.0	(4.0)	0.0	(0.1)	(0.6)
Net Cash Provided by (Used in) Financing Activities	(102.2)	(54.1)	(278.7)	273.2	(846.4)
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest, net	9.0	164.1	111.5	316.8	232.0
Cash paid (received) for income taxes, net	$ 0.3	$ 3.0	$ 3.0	$ (128.0)	$ 25.7