Segment Information, Revenue by Product (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue from External Customer [Line Items]
Operating revenues	$ 34,429	$ 36,137	$ 34,034	[1]	$ 33,474	$ 34,695	$ 34,726	$ 34,662	$ 35,167	[1],[2]	$ 138,074	$ 139,250	$ 125,987
Refining [Member]
Revenue from External Customer [Line Items]
Operating revenues											129,064	122,925	109,138
Refining [Member] | Gasoline and Blendstocks [Member]
Revenue from External Customer [Line Items]
Operating revenues											57,806	55,647	49,019
Refining [Member] | Distillates [Member]
Revenue from External Customer [Line Items]
Operating revenues											56,921	51,504	43,713
Refining [Member] | Petrochemicals [Member]
Revenue from External Customer [Line Items]
Operating revenues											4,281	3,908	4,253
Refining [Member] | Lubes and Asphalts [Member]
Revenue from External Customer [Line Items]
Operating revenues											1,643	2,033	1,948
Refining [Member] | Other Product Revenues [Member]
Revenue from External Customer [Line Items]
Operating revenues											8,413	9,833	10,205
Retail [Member]
Revenue from External Customer [Line Items]
Operating revenues											3,896	12,008	11,699
Retail [Member] | Fuel Sales Gasoline and Diesel [Member]
Revenue from External Customer [Line Items]
Operating revenues											3,226	10,045	9,730
Retail [Member] | Merchandise Sales and Other [Member]
Revenue from External Customer [Line Items]
Operating revenues											524	1,649	1,635
Retail [Member] | Heating Oil [Member]
Revenue from External Customer [Line Items]
Operating revenues											146	314	334
Ethanol [Member]
Revenue from External Customer [Line Items]
Operating revenues											5,114	4,317	5,150
Ethanol [Member] | Ethanol Product [Member]
Revenue from External Customer [Line Items]
Operating revenues											4,245	3,545	4,436
Ethanol [Member] | Distillers Grains [Member]
Revenue from External Customer [Line Items]
Operating revenues											$ 869	$ 772	$ 714

[1] The separation of our retail business was completed on May 1, 2013.

[2] The operations of the Aruba Refinery were suspended in March 2012.