Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Information for our Reportable Segments
Operating revenues	[1]	$ 19,649	$ 22,579	$ 54,947	$ 69,027
Lower of cost or market inventory valuation adjustment		0	0	(747)	0
Asset impairment loss		0	0	56	0
Operating income (loss)		892	2,139	2,952	5,712
Total Assets by Reportable Segment
Reportable segment assets		46,265		46,265		$ 44,227
Refining [Member]
Segment Information for our Reportable Segments
Operating revenues		18,718	21,739	52,302	66,618
Total Assets by Reportable Segment
Reportable segment assets		37,993		37,993		38,068
Ethanol [Member]
Segment Information for our Reportable Segments
Operating revenues		931	840	2,645	2,409
Total Assets by Reportable Segment
Reportable segment assets		1,277		1,277		1,016
Corporate and Other [Member]
Total Assets by Reportable Segment
Reportable segment assets		6,995		6,995		$ 5,143
Operating Segments [Member]
Segment Information for our Reportable Segments
Operating revenues		19,705	22,618	55,082	69,131
Operating Segments [Member] | Refining [Member]
Segment Information for our Reportable Segments
Operating revenues		18,718	21,739	52,302	66,618
Lower of cost or market inventory valuation adjustment				(697)
Asset impairment loss				56
Operating income (loss)		990	2,295	3,280	6,097
Operating Segments [Member] | Ethanol [Member]
Segment Information for our Reportable Segments
Operating revenues		987	879	2,780	2,513
Lower of cost or market inventory valuation adjustment				(50)
Asset impairment loss				0
Operating income (loss)		106	35	214	155
Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Operating revenues		56	39	135	104
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		56	39	135	104
Corporate, Non-Segment [Member] | Corporate and Other [Member]
Segment Information for our Reportable Segments
Asset impairment loss				0
Operating income (loss)		$ (204)	$ (191)	$ (542)	$ (540)

[1] Includes excise taxes on sales by certain of our international operations of $1,398 million and $1,538 million for the three months ended September 30, 2016 and 2015, respectively, and $4,263 million and $4,477 million for the nine months ended September 30, 2016 and 2015, respectively.