Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment information for our reportable segments
Operating revenues	$ 22,579	$ 34,408	$ 69,027	$ 102,985
Operating income (loss)	2,139	1,670	5,712	4,106
Total assets by reportable segment
Reportable segment assets	45,825		45,825		$ 45,550
Refining [Member]
Total assets by reportable segment
Reportable segment assets	38,558		38,558		40,103
Ethanol [Member]
Total assets by reportable segment
Reportable segment assets	959		959		954
Corporate and Other [Member]
Total assets by reportable segment
Reportable segment assets	6,308		6,308		$ 4,493
Operating Segments [Member] | Refining [Member]
Segment information for our reportable segments
Operating revenues	21,739	33,274	66,618	99,183
Operating income (loss)	2,295	1,664	6,097	4,023
Operating Segments [Member] | Ethanol [Member]
Segment information for our reportable segments
Operating revenues	840	1,134	2,409	3,802
Operating income (loss)	35	198	155	628
Corporate, Non-Segment [Member] | Corporate and Other [Member]
Segment information for our reportable segments
Operating income (loss)	(191)	(192)	(540)	(545)
Intersegment Eliminations [Member]
Segment information for our reportable segments
Operating revenues	39	21	104	55
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	$ 39	$ 21	$ 104	$ 55