Financial and Derivative Instruments (Details 2) - Commodity - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (245)	$ (21)
Sales and other operating revenues
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(238)	(12)
Purchased crude oil and products
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(7)	(9)
Other income
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 0	$ 0