Revenues and Segment Information, Assets (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Total Assets by Reportable Segment
Reportable segment assets	$ 49,099	$ 53,864
Corporate and Eliminations [Member]
Total Assets by Reportable Segment
Reportable segment assets	3,683	3,770
Refining [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	42,225	47,067
Renewable Diesel [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	1,504	1,412
Ethanol [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	$ 1,687	$ 1,615