Fresh Start Accounting - Enterprise Value Reconciliation (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 09, 2021
Reorganization, Chapter 11 [Line Items]
Enterprise Value				$ 4,851
Plus: Cash and cash equivalents	$ 1,079	$ 130	$ 905	40
Plus: Current liabilities	1,314	2,704		1,582
Plus: Asset retirement obligations (non-current portion)	265	323		236
Total assets	$ 14,376	$ 15,468		6,814
Restricted cash				86
Reorganization, Chapter 11, Fresh-Start Adjustment
Reorganization, Chapter 11 [Line Items]
Plus: Cash and cash equivalents				48
Plus: Current liabilities				0
Plus: Asset retirement obligations (non-current portion)				97
Plus: Other non-current liabilities				97
Total assets				359
Restricted cash				$ 8