Segment Information, Revenue by Product (Details) - USD ($) $ in Millions	3 Months Ended												12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	[2]	Jun. 30, 2016	[3]	Mar. 31, 2016	[4]	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Revenue from External Customer [Line Items]
Operating revenues	$ 26,392		$ 23,562	$ 22,254	$ 21,772	$ 20,712	$ 19,649		$ 19,584		$ 15,714		$ 93,980	[5]	$ 75,659	[5]	$ 87,804	[5]
Corporate [Member]
Revenue from External Customer [Line Items]
Operating revenues													5		0		0
Other Revenues [Member] | Corporate [Member]
Revenue from External Customer [Line Items]
Operating revenues													5		0		0
Refining [Member]
Revenue from External Customer [Line Items]
Operating revenues													90,651		71,968		84,521
Refining [Member] | Gasoline and Blendstocks [Member]
Revenue from External Customer [Line Items]
Operating revenues													40,362		33,450		38,983
Refining [Member] | Distillates [Member]
Revenue from External Customer [Line Items]
Operating revenues													42,074		32,576		38,093
Refining [Member] | Other Product Revenues [Member]
Revenue from External Customer [Line Items]
Operating revenues													8,215		5,942		7,445
Ethanol [Member]
Revenue from External Customer [Line Items]
Operating revenues													3,324		3,691		3,283
Ethanol [Member] | Ethanol [Member]
Revenue from External Customer [Line Items]
Operating revenues													2,764		3,105		2,628
Ethanol [Member] | Distillers Grains [Member]
Revenue from External Customer [Line Items]
Operating revenues													$ 560		$ 586		$ 655

[1] During the quarter ended December 31, 2017, we recognized an income tax benefit of $1.9 billion related to Tax Reform as described in Note 14.

[2] During the quarter ended September 30, 2016, we recognized a tax benefit of $42 million related to the Aruba Disposition as described in Note 2.

[3] During the quarter ended June 30, 2016, we recognized a favorable noncash lower of cost or market inventory valuation adjustment of $454 million as described in Note 4 and an asset impairment loss of $56 million related to the Aruba Disposition as described in Note 2.

[4] During the quarter ended March 31, 2016, we recognized a favorable noncash lower of cost or market inventory valuation adjustment of $293 million as described in Note 4.

[5] Includes excise taxes on sales by certain of our international operations of $5,573 million, $5,493 million, and $5,980 million for the years ended December 31, 2017, 2016, and 2015.