Segment Information, Revenue by Product (Details) - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2015	[1]	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Revenue from External Customer [Line Items]
Operating revenues	$ 18,777		$ 22,579	$ 25,118	$ 21,330	$ 27,859	$ 34,408	$ 34,914	$ 33,663	$ 87,804	[2]	$ 130,844	[2]	$ 138,074	[2]
Refining [Member]
Revenue from External Customer [Line Items]
Operating revenues										84,521		126,004		129,064
Refining [Member] | Gasoline and Blendstocks [Member]
Revenue from External Customer [Line Items]
Operating revenues										38,983		56,846		57,806
Refining [Member] | Distillates [Member]
Revenue from External Customer [Line Items]
Operating revenues										38,093		57,521		56,921
Refining [Member] | Petrochemicals [Member]
Revenue from External Customer [Line Items]
Operating revenues										1,824		3,759		4,281
Refining [Member] | Lubes and Asphalts [Member]
Revenue from External Customer [Line Items]
Operating revenues										874		1,397		1,643
Refining [Member] | Other Product Revenues [Member]
Revenue from External Customer [Line Items]
Operating revenues										4,747		6,481		8,413
Ethanol [Member]
Revenue from External Customer [Line Items]
Operating revenues										3,283		4,840		5,114
Ethanol [Member] | Ethanol [Member]
Revenue from External Customer [Line Items]
Operating revenues										2,628		4,192		4,245
Ethanol [Member] | Distillers Grains [Member]
Revenue from External Customer [Line Items]
Operating revenues										655		648		869
Retail [Member]
Revenue from External Customer [Line Items]
Operating revenues										0		0		3,896
Retail [Member] | Fuel Sales Gasoline and Diesel [Member]
Revenue from External Customer [Line Items]
Operating revenues										0		0		3,226
Retail [Member] | Merchandise Sales and Other [Member]
Revenue from External Customer [Line Items]
Operating revenues										0		0		524
Retail [Member] | Home Heating Oil [Member]
Revenue from External Customer [Line Items]
Operating revenues										$ 0		$ 0		$ 146

[1] Operating income for the quarter ended December 31, 2015 reflects a noncash lower of cost or market inventory valuation adjustment of $790 million, as described in Note 6.

[2] Includes excise taxes on sales by certain of our international operations of $5,980 million, $5,901 million, and $5,459 million.