Revenues and Segment Information, Disaggregation of Revenue by Product (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Revenue by Segment
Revenues	[1]	$ 20,806	$ 22,102
Refining [Member]
Revenue by Segment
Revenues		19,469	20,985
Refining [Member] | Gasoline and Blendstocks [Member]
Revenue by Segment
Revenues		8,729	8,244
Refining [Member] | Distillates [Member]
Revenue by Segment
Revenues		8,581	10,663
Refining [Member] | Other Product Revenues [Member]
Revenue by Segment
Revenues		2,159	2,078
Renewable Diesel [Member]
Revenue by Segment
Revenues		352	306
Renewable Diesel [Member] | Renewable Diesel [Member]
Revenue by Segment
Revenues		352	306
Ethanol [Member]
Revenue by Segment
Revenues		985	811
Ethanol [Member] | Ethanol [Member]
Revenue by Segment
Revenues		752	629
Ethanol [Member] | Distillers Grains [Member]
Revenue by Segment
Revenues		$ 233	$ 182

[1] Includes excise taxes on sales by certain of our international operations of $1,120 million and $1,368 million for the three months ended March 31, 2021 and 2020, respectively.