Debt (Narrative) (Details) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
	Jun. 16, 2022	Dec. 30, 2022	Jun. 16, 2022	Dec. 31, 2021	Dec. 25, 2020
Debt Instrument [Line Items]
Debt instrument, face amount		$ 3,534.1
Long-term Debt, Gross		3,048.5		$ 0.0
Debt Issuance Costs, Net		20.8		6.1
Repayments of Debt		50.1	$ 904.6	137.5	$ 139.5
Debtor Reorganization Items, Write-off of Debt Issuance Costs and Debt Discounts		0.0	$ 0.0	23.1	10.2
prepayment premium	1.00%		1.00%
Issuance of external debt	$ 650.0	0.0	$ 650.0	0.0	$ 0.0
4.75% senior notes due April 2023
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Extinguishment of Debt, Amount	133.7
Five Point Six Two Five Percent Note
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Five Point Five Percent Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
2017 Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Debt Issuance Costs, Net		0.0		0.2
5.75% senior notes due August 2022
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Term Loan and New Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Term Loan due 2025 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Ten Point Zero Percent First Lien Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 495.0	495.0	$ 495.0
Stated interest rate	10.00%		10.00%
Debt Instrument, Redemption Price, Percentage	100.00%
Ten Point Zero Percent First Lien Notes [Member] | Reorganization, Chapter 11, Plan Effect Adjustment
Debt Instrument [Line Items]
Debt Issuance Costs, Gross	$ 5.1		$ 5.1
Term Loans due Sept 2024 and Feb 2025 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	1,762.6
Ten Point Zero Percent Second Lien Notes (New 2L Notes)
Debt Instrument [Line Items]
Debt instrument, face amount	$ 322.9	321.9	$ 322.9
Stated interest rate	10.00%		10.00%
Extinguishment of Debt, Amount	$ 322.9
Guaranteed Unsecured Notes
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	1,512.2
9.50% debentures due May 2022
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Extinguishment of Debt, Amount	10.4
8.00% debentures due March 2023
Debt Instrument [Line Items]
Debt instrument, face amount		0.0
Extinguishment of Debt, Amount	4.4
2017 Replacement Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount	1,392.9	$ 1,374.1	$ 1,392.9
Long-term Debt, Weighted Average Interest Rate, at Point in Time		9.99%
Debt Issuance Costs, Net		$ 0.0		0.0
2017 Replacement Term Loan | Reorganization, Chapter 11, Plan Effect Adjustment
Debt Instrument [Line Items]
Debt instrument, face amount	1,392.9		1,392.9
2018 Replacement Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount	369.7	$ 364.8	369.7
Long-term Debt, Weighted Average Interest Rate, at Point in Time		10.24%
Debt Issuance Costs, Net		$ 0.0		0.0
2018 Replacement Term Loan | Reorganization, Chapter 11, Plan Effect Adjustment
Debt Instrument [Line Items]
Debt instrument, face amount	$ 369.7		$ 369.7
Eleven Point Five Percent First Lien Senior Secured Notes
Debt Instrument [Line Items]
Debt instrument, face amount		650.0
Stated interest rate	11.50%		11.50%
Debt Instrument, Redemption Price, Percentage	100.00%
Debt Issuance Costs, Net		20.8		0.0
Ten Point Zero Percent Second Lien Notes due 2029
Debt Instrument [Line Items]
Debt instrument, face amount		328.3
Stated interest rate	10.00%		10.00%
Debt Instrument, Redemption Price, Percentage	100.00%
Debt Issuance Costs, Net		0.0		0.0
Ten Point Zero Percent Second Lien Notes due 2029 | Reorganization, Chapter 11, Plan Effect Adjustment
Debt Instrument [Line Items]
Debt instrument, face amount	$ 375.0		$ 375.0
Receivables Financing Facility
Debt Instrument [Line Items]
Debt instrument, face amount	$ 200.0		$ 200.0
Debentures | 4.75% senior notes due April 2023
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Debentures | Five Point Six Two Five Percent Note
Debt Instrument [Line Items]
Stated interest rate	5.625%		5.625%
Debt Issuance Costs, Net		0.0		0.0
Debentures | Five Point Five Percent Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Debentures | 5.75% senior notes due August 2022
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Debentures | 9.50% debentures due May 2022
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Debentures | 8.00% debentures due March 2023
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Senior Notes | 4.75% senior notes due April 2023
Debt Instrument [Line Items]
Stated interest rate	4.75%		4.75%
Senior Notes | Five Point Five Percent Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	5.50%		5.50%
Senior Notes | 5.75% senior notes due August 2022
Debt Instrument [Line Items]
Stated interest rate	5.75%		5.75%
Senior Notes | Ten Point Zero Percent Second Lien Notes (New 2L Notes)
Debt Instrument [Line Items]
Stated interest rate	10.00%		10.00%
Senior Notes | Eleven Point Five Percent First Lien Senior Secured Notes
Debt Instrument [Line Items]
Stated interest rate	11.50%		11.50%
Secured Debt | Term Loan and New Term Loan
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Secured Debt | Term Loan due 2025 [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		0.0
Secured Debt | Ten Point Zero Percent First Lien Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0.0		5.9
Secured Debt | Ten Point Zero Percent Second Lien Notes (New 2L Notes)
Debt Instrument [Line Items]
Debt Issuance Costs, Net		$ 0.0		$ 0.0
Option A | Ten Point Zero Percent First Lien Notes [Member]
Debt Instrument [Line Items]
Repurchase percentage	101.00%
Option A | Eleven Point Five Percent First Lien Senior Secured Notes
Debt Instrument [Line Items]
Repurchase percentage	101.00%
Option A | Ten Point Zero Percent Second Lien Notes due 2029
Debt Instrument [Line Items]
Repurchase percentage	101.00%
Option B | Ten Point Zero Percent First Lien Notes [Member]
Debt Instrument [Line Items]
Repurchase percentage	100.00%
Option B | Eleven Point Five Percent First Lien Senior Secured Notes
Debt Instrument [Line Items]
Repurchase percentage	100.00%
Option B | Ten Point Zero Percent Second Lien Notes due 2029
Debt Instrument [Line Items]
Repurchase percentage	100.00%
Debentures | 9.50% debentures due May 2022
Debt Instrument [Line Items]
Stated interest rate	9.50%		9.50%
Debentures | 8.00% debentures due March 2023
Debt Instrument [Line Items]
Stated interest rate	8.00%		8.00%
London Interbank Offered Rate (LIBOR) [Member] | 2017 Replacement Term Loan
Debt Instrument [Line Items]
Variable interest rate	5.25%
London Interbank Offered Rate (LIBOR) [Member] | 2017 Replacement Term Loan | Minimum
Debt Instrument [Line Items]
Variable interest rate	0.75%
London Interbank Offered Rate (LIBOR) [Member] | 2018 Replacement Term Loan
Debt Instrument [Line Items]
Variable interest rate	5.50%
London Interbank Offered Rate (LIBOR) [Member] | 2018 Replacement Term Loan | Minimum
Debt Instrument [Line Items]
Variable interest rate	0.75%
Alternate Base Rate | 2017 Replacement Term Loan
Debt Instrument [Line Items]
Variable interest rate	4.25%
Alternate Base Rate | 2017 Replacement Term Loan | Minimum
Debt Instrument [Line Items]
Variable interest rate	1.75%
Alternate Base Rate | 2018 Replacement Term Loan
Debt Instrument [Line Items]
Variable interest rate	4.50%
Alternate Base Rate | 2018 Replacement Term Loan | Minimum
Debt Instrument [Line Items]
Variable interest rate	1.75%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | 2017 and 2018 Replacement Term Loan | One Month
Debt Instrument [Line Items]
Variable interest rate	0.11448%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | 2017 and 2018 Replacement Term Loan | Three Months
Debt Instrument [Line Items]
Variable interest rate	0.26161%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | 2017 and 2018 Replacement Term Loan | Six Months
Debt Instrument [Line Items]
Variable interest rate	0.42826%