Segment Information, Revenue by Product (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
Revenue from External Customer [Line Items]
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
Refining [Member]
Revenue from External Customer [Line Items]
Operating revenues											109,138	69,854	55,516
Refining [Member] | Gasoline and Blendstocks [Member]
Revenue from External Customer [Line Items]
Operating revenues											49,019	33,491	27,322
Refining [Member] | Distillates [Member]
Revenue from External Customer [Line Items]
Operating revenues											43,713	26,402	20,526
Refining [Member] | Petrochemicals [Member]
Revenue from External Customer [Line Items]
Operating revenues											4,253	3,161	2,177
Refining [Member] | Lubes and Asphalts [Member]
Revenue from External Customer [Line Items]
Operating revenues											1,948	1,315	1,126
Refining [Member] | Other Product Revenues [Member]
Revenue from External Customer [Line Items]
Operating revenues											10,205	5,485	4,365
Retail [Member]
Revenue from External Customer [Line Items]
Operating revenues											11,699	9,339	7,885
Retail [Member] | Fuel Sales Gasoline and Diesel [Member]
Revenue from External Customer [Line Items]
Operating revenues											9,730	7,498	6,148
Retail [Member] | Merchandise Sales and Other [Member]
Revenue from External Customer [Line Items]
Operating revenues											1,635	1,581	1,505
Retail [Member] | Home Heating Oil [Member]
Revenue from External Customer [Line Items]
Operating revenues											334	260	232
Ethanol [Member]
Revenue from External Customer [Line Items]
Operating revenues											5,150	3,040	1,198
Ethanol [Member] | Ethanol Product [Member]
Revenue from External Customer [Line Items]
Operating revenues											4,436	2,647	1,032
Ethanol [Member] | Distillers Grains [Member]
Revenue from External Customer [Line Items]
Operating revenues											$ 714	$ 393	$ 166

[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.