Borrowings and Other Debt Obligations - Narrative (Details) - USD ($)		1 Months Ended	3 Months Ended			11 Months Ended	12 Months Ended
	Oct. 20, 2021	Dec. 31, 2019	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 13, 2019	Dec. 31, 2021	Dec. 31, 2020	Oct. 27, 2021	Aug. 04, 2020	Dec. 12, 2019
Debt Instrument [Line Items]
Interest paid on early redemption of debt							$ 71,000,000
Bond Redemption Premium		$ 0				$ 0	131,000,000	$ 0
Gain (loss) on extinguishment of debt	$ (2,000,000)	$ 0				$ 0	(170,000,000)	0
Long-term debt			$ 2,372,000,000				2,372,000,000	2,553,000,000
Debt issuance costs, gross			25,000,000				25,000,000
Debt related commitment fees and debt issuance costs			15,000,000				15,000,000
Permitted borrowing				$ 400,000,000
Debt instrument covenant debt amount in excess default				300,000,000	$ 175,000,000
Minimum book value of pledged assets for covenants under LC credit agreement				1,000,000,000	$ 1,250,000,000
Amount of debt redeemable if minimum liquidity requirement met				500,000,000
Minimum aggregate liquidity requirment covenant in order to redeem debt				$ 400,000,000
Debt instrument, unused borrowing capacity, amount			34,000,000				34,000,000
ABL Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term debt								0
Line of credit facility, maximum borrowing capacity											$ 450,000,000
Amended LC Credit Agreement [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity											215,000,000
Senior Notes 6.5 Percent Due 2028
Debt Instrument [Line Items]
Stated interest rate on debt				6.50%
Face amount of debt				$ 500,000,000
Bond Redemption Premium							22,000,000
Gain (loss) on extinguishment of debt, before write off of debt issuance cost							37,000,000
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
Exit Notes, Takeback Notes | Exit Notes, 11.00 Percent Due 2024 [Member]
Debt Instrument [Line Items]
Face amount of debt											$ 500,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Bond Redemption Premium							103,000,000
Long-term debt			300,000,000				300,000,000	2,098,000,000
Senior Notes [Member] | Exit Notes, 11.00 Percent Due 2024 [Member]
Debt Instrument [Line Items]
Stated interest rate on debt		11.00%									11.00%
Face amount of debt											$ 2,100,000,000
Debt and lease obligation											$ 2,100,000,000
Senior Notes [Member] | 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 [Member] | Senior Notes 6.5 Percent Due 2028
Debt Instrument [Line Items]
Stated interest rate on debt										6.50%
Long-term debt			488,000,000				488,000,000	0
Senior Notes [Member] | Senior Notes 8.625 Percent Due 2030
Debt Instrument [Line Items]
Stated interest rate on debt										8.625%
Long-term debt			1,584,000,000				1,584,000,000	0
LC Credit Agreement Letters of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding, amount			181,000,000				$ 181,000,000
Debt instrument, basis percentage							3.50%
Debt instrument, fronting fee, basis percentage							0.125%
Debt instrument, unused commitment fee, basis percentage							0.50%
Committed Letters of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding, cash collateral			158,000,000				$ 158,000,000
Letters of credit outstanding, amount								$ 342,000,000
Uncommitted Letters of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding, amount			$ 161,000,000				$ 161,000,000
Exit Notes
Debt Instrument [Line Items]
Debt instrument, repurchased face amount	200,000,000
Interest paid on early redemption of debt	8,000,000
Bond Redemption Premium	$ 6,000,000
Debt tender redemption									$ 1,600,000,000