Fresh-Start Accounting - Reorganization Items (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended	9 Months Ended
	Jun. 16, 2022	Sep. 30, 2022	Sep. 30, 2022	Sep. 24, 2021	Jun. 16, 2022	Sep. 24, 2021
Reorganizations [Abstract]
Cash Paid, Reorganization items			$ 9.9		$ 304.1	$ 209.1
Reorganization, Chapter 11 [Line Items]
Debtor Reorganization Items, Legal and Advisory Professional Fees		$ 14.2	17.7	$ 119.4	161.1	306.6
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, Gain (Loss) on Settlement of Other Claims, Net			0.0		5.4	(0.5)
Reorganization items, net		14.2	17.7	126.2	630.9	329.2
Debtor Reorganization Items, Write-off of Debt Issuance Costs and Debt Discounts		$ 0.0	0.0	$ 6.8	0.0	23.1
Cash Paid, Reorganization items			9.9		304.1	209.1
Reorganization, Chapter 11, Plan Effect Adjustment
Reorganization, Chapter 11 [Line Items]
Gain on settlement of liabilities subject to compromise	$ 943.7		0.0		(943.7)	0.0
Reorganization, Chapter 11, Fresh-Start Adjustment
Reorganization, Chapter 11 [Line Items]
Reorganization Items, net, Loss on Fresh-Start Adjustments	$ (1,354.6)		$ 0.0		$ 1,354.6	$ 0.0