Derivatives - Schedule of mark-to-market impact and commodity derivative settlements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss) on derivatives, net	$ 54	$ 12	$ 0
Net settlements of derivative instruments	356	123	65
Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivative instruments, net	16	(27)	(124)
Realized gain (loss) on derivatives, net	$ (399)	$ 143	$ 52