Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Information for our Reportable Segments
Operating revenues	[1]	$ 19,584	$ 25,118	$ 35,298	$ 46,448
Lower of cost or market inventory valuation adjustment		(454)	0	(747)	0
Asset impairment loss		56	0	56	0
Operating income (loss)		1,231	2,078	2,060	3,573
Total Assets by Reportable Segment
Reportable segment assets		45,452		45,452		$ 44,227
Refining [Member]
Segment Information for our Reportable Segments
Operating revenues		18,664	24,350	33,584	44,879
Total Assets by Reportable Segment
Reportable segment assets		38,634		38,634		38,068
Ethanol [Member]
Segment Information for our Reportable Segments
Operating revenues		920	768	1,714	1,569
Total Assets by Reportable Segment
Reportable segment assets		1,005		1,005		1,016
Corporate and Other [Member]
Total Assets by Reportable Segment
Reportable segment assets		5,813		5,813		$ 5,143
Operating Segments [Member]
Segment Information for our Reportable Segments
Operating revenues		19,629	25,155	35,377	46,513
Operating Segments [Member] | Refining [Member]
Segment Information for our Reportable Segments
Operating revenues		18,664	24,350	33,584	44,879
Lower of cost or market inventory valuation adjustment		(434)		(697)
Asset impairment loss		56		56
Operating income (loss)		1,332	2,161	2,290	3,802
Operating Segments [Member] | Ethanol [Member]
Segment Information for our Reportable Segments
Operating revenues		965	805	1,793	1,634
Lower of cost or market inventory valuation adjustment		(20)		(50)
Asset impairment loss		0		0
Operating income (loss)		69	108	108	120
Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Operating revenues		45	37	79	65
Intersegment Eliminations [Member] | Refining [Member]
Segment Information for our Reportable Segments
Operating revenues		0	0	0	0
Intersegment Eliminations [Member] | Ethanol [Member]
Segment Information for our Reportable Segments
Operating revenues		45	37	79	65
Corporate, Non-Segment [Member] | Corporate and Other [Member]
Segment Information for our Reportable Segments
Asset impairment loss		0		0
Operating income (loss)		$ (170)	$ (191)	$ (338)	$ (349)

[1] Includes excise taxes on sales by certain of our international operations of $1,470 million and $1,513 million for the three months ended June 30, 2016 and 2015, respectively, and $2,865 million and $2,939 million for the six months ended June 30, 2016 and 2015, respectively.