Derivative Instruments - Effect of Derivative Instruments on the Condensed Consolidated Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Effect of derivative instruments on the Consolidated Balance Sheet
Total	$ 3	$ (156)	$ 129	$ (613)
Gas contracts
Effect of derivative instruments on the Consolidated Balance Sheet
Cash received (paid) on settlement of derivative instruments	55	(202)	235	(405)
Non-cash gain (loss) on derivative instruments	(40)	2	(93)	(47)
Oil contracts
Effect of derivative instruments on the Consolidated Balance Sheet
Cash received (paid) on settlement of derivative instruments	0	(57)	3	(318)
Non-cash gain (loss) on derivative instruments	$ (12)	$ 101	$ (16)	$ 157