Revenues and Segment Information, Assets (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Total Assets by Reportable Segment
Reportable segment assets	$ 55,456	$ 51,774
Corporate and Eliminations [Member]
Total Assets by Reportable Segment
Reportable segment assets	4,653	5,448
Refining [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	46,843	42,939
Renewable Diesel [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	2,215	1,659
Ethanol [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	$ 1,745	$ 1,728