Borrowings and Other Debt Obligations - Narrative (Details) - USD ($)		1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 20, 2021	Jan. 31, 2024	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Oct. 24, 2023	Sep. 30, 2023	Mar. 24, 2023	Oct. 17, 2022	Oct. 27, 2021	Aug. 28, 2020	Dec. 12, 2019
Debt Instrument [Line Items]
Bond Redemption Premium					$ 5,000,000	$ 5,000,000	$ 131,000,000
Gain (loss) on extinguishment of debt	$ (2,000,000)
Debt and lease obligation					1,901,000,000
Letters of credit outstanding, cash collateral			$ 199,000,000			199,000,000
Line of credit facility, maximum borrowing capacity											$ 400,000,000
Letters of credit outstanding, amount			395,000,000		376,000,000	395,000,000
Minimum liquidity amount								$ 400,000,000			250,000,000
Debt Instrument, Covenant, Maximum Net Leverage Ratio								2.00
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net					18,000,000
Credit Agreement Minimum Liquidity Requirement					250,000,000
Senior Notes 8.75 Percent Due 2024
Debt Instrument [Line Items]
Bond Redemption Premium				$ 22,000,000
Gain (loss) on extinguishment of debt, before write off of debt issuance cost				$ 37,000,000
Senior Notes 6.5 Percent Due 2028
Debt Instrument [Line Items]
Stated interest rate on debt				6.50%					6.50%
Face amount of debt				$ 500,000,000
Bond Redemption Premium				$ 2,000,000
Repayments of Senior Debt					243,000,000	8,000,000
Senior Notes 6.5 Percent Due 2028 | Subsequent Event
Debt Instrument [Line Items]
Face amount of debt		$ 97,000,000
Repayments of Senior Debt		$ 151,000,000
Senior Notes 8.625 Percent Due 2030
Debt Instrument [Line Items]
Stated interest rate on debt												8.625%
Face amount of debt			1,600,000,000			1,600,000,000						$ 1,600,000,000
Amended LC Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					400,000,000			550,000,000		$ 400,000,000				$ 400,000,000
Senior Notes
Debt Instrument [Line Items]
Additional Repayments Of Senior Debt			20,000,000
Long-term debt			2,193,000,000		1,830,000,000	2,193,000,000
Senior Notes | Exit Notes, 11.00 Percent Due 2024
Debt Instrument [Line Items]
Stated interest rate on debt														11.00%
Face amount of debt														$ 2,100,000,000
Bond Redemption Premium					3,000,000	5,000,000
Long-term debt			105,000,000		0	105,000,000
Senior Notes | Senior Notes 8.75 Percent Due 2024
Debt Instrument [Line Items]
Stated interest rate on debt													8.75%
Face amount of debt													$ 500,000,000
Senior Notes | Senior Notes 6.5 Percent Due 2028
Debt Instrument [Line Items]
Long-term debt			471,000,000		92,000,000	471,000,000
Long-term debt			482,000,000		243,000,000	482,000,000
Senior Notes | Senior Notes 8.625 Percent Due 2030
Debt Instrument [Line Items]
Long-term debt			1,586,000,000		1,587,000,000	1,586,000,000
Long-term debt			1,586,000,000		1,587,000,000	1,586,000,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net			14,000,000		13,000,000	14,000,000
Line of Credit | Exit Notes | Revolving Credit Facility
Debt Instrument [Line Items]
Minimum liquidity amount										300,000,000
Debt Instrument, Covenant, Minimum Interest Coverage Ratio					2.50					$ 2.50	2.50
Debt Instrument, Covenant, Maximum Net Leverage Ratio					3.50						3.50
Debt Instrument, Covenant, Maximum Secured Net Leverage Ratio					1.50						$ 1.50
Line of Credit | Amended LC Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					550,000,000			200,000,000
Secured Debt | Exit Notes, 11.00 Percent Due 2024
Debt Instrument [Line Items]
Long-term debt			125,000,000		0	125,000,000
Secured Debt | Senior Notes 6.5 Percent Due 2028
Debt Instrument [Line Items]
Long-term debt			492,000,000		248,000,000	492,000,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net			10,000,000		5,000,000	10,000,000
LC Credit Agreement Letters of Credit
Debt Instrument [Line Items]
Face amount of debt					0
LC Credit Agreement Letters of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount			195,000,000		270,000,000	195,000,000
Uncommitted Letters of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, cash collateral					101,000,000
Letters of credit outstanding, amount			200,000,000		106,000,000	200,000,000
Exit Notes
Debt Instrument [Line Items]
Debt instrument, repurchased face amount	1,800,000,000		$ 175,000,000		125,000,000	$ 175,000,000
Bond Redemption Premium	$ 109,000,000
Performance Letters of Credit
Debt Instrument [Line Items]
Letters of credit outstanding, amount					218,000,000
Performance Letters of Credit | Amended LC Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity								250,000,000
Performance Letters of Credit Or Other Borrowings
Debt Instrument [Line Items]
Letters of credit outstanding, amount					$ 52,000,000
Performance Letters of Credit Or Other Borrowings | Amended LC Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity								$ 300,000,000