Financial and Derivative Instruments - Effect of Derivatives (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Pre-tax deferred losses	$ (2)	$ 0
Commodity
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Effect of derivatives, gain (loss), net	(977)	(316)
Commodity | Sales and other operating revenues
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Effect of derivatives, gain (loss), net	(873)	(274)
Commodity | Purchased crude oil and products
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Effect of derivatives, gain (loss), net	(105)	(3)
Commodity | Other income
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Effect of derivatives, gain (loss), net	$ 1	$ (39)