Operating Segments, Results (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		Dec. 31, 2010		Dec. 31, 2009
Segment Reporting Information, Operating Income (Loss) [Abstract]
Revenues	$ 7,713		$ 8,101		$ 7,963		$ 6,526		$ 5,513		$ 5,320		$ 5,143		$ 4,607		$ 30,303		$ 20,583		$ 16,872
Total Segment Operating Income																	1,268		352		138
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Corporate and unallocated costs																	(188)		(212)		(195)
Operating Income (Loss) (b) (c)	(155)	[1]	597	[1]	419	[1]	219	[1]	70	[1]	129	[1]	143	[1]	(202)	[1]	1,080	[1],[2]	140	[1],[2]	(57)	[2]
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Interest and financing costs																	(177)		(157)		(130)
Interest income and other																	2		3		4
Foreign currency exchange gain																	(2)		2		(5)
Other income (expense)																	2		(13)		0
Earnings (Loss) Before Income Taxes																	905		(25)		(188)
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments [Abstract]
Depreciation and Amortization Expense																	417		422		426
Capital Expenditures																	320		287		401
Identifiable Assets	9,892								8,732								9,892		8,732		8,070
Table Footnotes [Abstract]
Excise and sales taxes																	376		330		283
Losses (gains) on asset impairments and sales of assets																	51		20		12
Goodwill write-off																	0		10		43
Business interruption and property damage recoveries					37				67								37		67
Gain on elimination of postretirement benefits													48						48
Refining: [Member]
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating Income (Loss) (b) (c)																	1,179	[3]	255	[3]	55	[3]
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments [Abstract]
Depreciation and Amortization Expense																	369		365		359
Capital Expenditures																	262		263		356
Identifiable Assets	8,152								7,303								8,152		7,303		6,690
Refined products [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Revenues																	29,058		19,038		15,674
Crude oil resales and other [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Revenues																	747		1,039		691
Retail: [Member]
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Operating Income (Loss) (b) (c)																	89		97		83
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments [Abstract]
Depreciation and Amortization Expense																	38		39		39
Capital Expenditures																	41		22		14
Identifiable Assets	644								619								644		619		656
Fuel (a) [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Revenues																	5,095	[4]	3,583	[4]	3,000	[4]
Merchandise and other [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Revenues																	224		227		235
Intersegment sales from Refining to Retail [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
Intersegment sales from Refining to Retail																	(4,821)		(3,304)		(2,728)
Corporate [Member]
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments [Abstract]
Depreciation and Amortization Expense																	10		18		28
Capital Expenditures																	17		2		31
Identifiable Assets	$ 1,096								$ 810								$ 1,096		$ 810		$ 724

[1] Includes impairment charges related to the change in scope of a capital project at our Los Angeles refinery of $48 million and $20 million, for the three months ended June 30, 2011 and March 31, 2010, respectively. Also includes a $48 million gain for the three months ended June 30, 2010, from the elimination of postretirement life insurance benefits for current and future retirees.

[2] Includes a $48 million gain for the year ended December 31, 2010, from the elimination of postretirement life insurance benefits for current and future retirees.

[3] Includes losses related to the change in scope of a capital project at our Los Angeles refinery of $51 million, $20 million and $12 million for the years ended December 31, 2011, 2010 and 2009, respectively. The loss on asset disposals and impairments is included in refining segment operating income. Includes goodwill write-off related to two separate reporting units for $10 million and $43 million for the years ended December 31, 2010 and 2009, respectively. Also includes $37 million and $67 million in business interruption and property damage recoveries related to the April 2, 2010 incident at our Washington refinery for the year ended December 31, 2011 and 2010, respectively.

[4] Federal and state motor fuel taxes on sales by our retail segment are included in both revenues and cost of sales in our statements of consolidated operations. These taxes, excluding credits, totaled $376 million, $330 million and $283 million for the years ended December 31, 2011, 2010 and 2009, respectively.