Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment information for our reportable segments
Operating revenues	$ 25,118	$ 34,914	$ 46,448	$ 68,577
Operating income (loss)	2,078	1,085	3,573	2,436
Total assets by reportable segment
Reportable segment assets	47,599		47,599		$ 45,550
Refining [Member]
Total assets by reportable segment
Reportable segment assets	39,813		39,813		40,103
Ethanol [Member]
Total assets by reportable segment
Reportable segment assets	961		961		954
Corporate and Other [Member]
Total assets by reportable segment
Reportable segment assets	6,825		6,825		$ 4,493
Operating Segments [Member] | Refining [Member]
Segment information for our reportable segments
Operating revenues	24,350	33,457	44,879	65,909
Operating income (loss)	2,161	1,079	3,802	2,359
Operating Segments [Member] | Ethanol [Member]
Segment information for our reportable segments
Operating revenues	768	1,457	1,569	2,668
Operating income (loss)	108	187	120	430
Corporate, Non-Segment [Member] | Corporate and Other [Member]
Segment information for our reportable segments
Operating income (loss)	(191)	(181)	(349)	(353)
Intersegment Eliminations [Member]
Segment information for our reportable segments
Operating revenues	37	9	65	34
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	$ 37	$ 9	$ 65	$ 34