Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011 segments	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Number of Reportable Segments											3
Segment information for our three reportable segments
Operating revenues	$ 34,673	[1]	$ 33,713	[2]	$ 31,293	$ 26,308	$ 22,164	$ 21,015	$ 20,561	$ 18,493	$ 125,987	$ 82,233	$ 64,599
Intersegment revenues											8,810	6,661	5,274
Depreciation and amortization expense											1,534	1,405	1,361
Operating income (loss)	167	[1]	1,979	[2]	1,290	244	378	590	904	4	3,680	1,876	83
Total expenditures for long-lived assets											2,987	2,234	2,448
Refining [Member]
Segment information for our three reportable segments
Operating revenues											109,138	69,854	55,516
Intersegment revenues											8,665	6,416	5,137
Depreciation and amortization expense											1,338	1,210	1,194
Operating income (loss)											3,516	1,903	247
Total expenditures for long-lived assets											2,556	2,084	2,338
Retail [Member]
Segment information for our three reportable segments
Operating revenues											11,699	9,339	7,885
Intersegment revenues											0	0	0
Depreciation and amortization expense											115	108	101
Operating income (loss)											381	346	293
Total expenditures for long-lived assets											134	102	66
Ethanol [Member]
Segment information for our three reportable segments
Operating revenues											5,150	3,040	1,198
Intersegment revenues											145	245	137
Depreciation and amortization expense											39	36	18
Operating income (loss)											396	209	165
Total expenditures for long-lived assets											32	0	5
Corporate [Member]
Segment information for our three reportable segments
Operating revenues											0	0	0
Intersegment revenues											0	0	0
Depreciation and amortization expense											42	51	48
Operating income (loss)											(613)	(582)	(622)
Total expenditures for long-lived assets											$ 265	$ 48	$ 39

[1] Includes the operations related to the Meraux Acquisition beginning October 1, 2011.

[2] Includes the operations related to the Pembroke Acquisition beginning August 1, 2011.