Derivative and Hedging Activities - Oil, Natural Gas and NGL Revenues (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Feb. 09, 2021	Mar. 31, 2021	Mar. 31, 2020
Derivative [Line Items]
Total revenues and other	$ 260	$ 880	$ 2,525
Not designated as hedging instrument | Oil, natural gas and NGL sales
Derivative [Line Items]
Losses on terminated cash flow hedges	(3)	0	(9)
Total revenues and other	(382)	46	907
Not designated as hedging instrument | Oil, natural gas and NGL sales | Commodity contract
Derivative [Line Items]
Gains (losses) on undesignated oil and natural gas derivatives	$ (379)	$ 46	$ 916