Segment Information (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Segment information for our three reportable segments
Operating revenues from external customers	$ 33,713	$ 21,015	$ 91,314	$ 60,069
Intersegment revenues	2,283	1,649	6,691	4,859
Operating income (loss)	1,979	590	3,513	1,498
Total assets by reportable segment
Reportable segment assets	41,683		41,683		37,621
Refining [Member]
Segment information for our three reportable segments
Operating revenues from external customers	29,177	17,811	78,660	51,104
Intersegment revenues	2,258	1,576	6,566	4,675
Operating income (loss)	1,947	590	3,476	1,479
Total assets by reportable segment
Reportable segment assets	35,541		35,541		30,363
Retail [Member]
Segment information for our three reportable segments
Operating revenues from external customers	3,053	2,360	8,865	6,893
Intersegment revenues	0	0	0	0
Operating income (loss)	97	105	298	285
Total assets by reportable segment
Reportable segment assets	1,933		1,933		1,925
Ethanol [Member]
Segment information for our three reportable segments
Operating revenues from external customers	1,483	844	3,789	2,072
Intersegment revenues	25	73	125	184
Operating income (loss)	107	47	215	139
Total assets by reportable segment
Reportable segment assets	879		879		953
Corporate [Member]
Segment information for our three reportable segments
Operating revenues from external customers	0	0	0	0
Intersegment revenues	0	0	0	0
Operating income (loss)	(172)	(152)	(476)	(405)
Total assets by reportable segment
Reportable segment assets	$ 3,330		$ 3,330		$ 4,380