Financial and Derivative Instruments (Details 1) - Commodity - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Consolidated Statement of Income: The Effect of Derivatives not Designated as Hedging Instruments
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (182)	$ 121	$ (203)	$ 285
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	(165)	116	(177)	278
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	(18)	6	(26)	10
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	$ 1	$ (1)	$ 0	$ (3)