Segment Information, Total Assets by Reportable Segments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Total Assets by Reportable Segments
Reportable segment assets	$ 50,158	$ 46,173
Operating Segments [Member] | Refining [Member]
Total Assets by Reportable Segments
Reportable segment assets	40,382	38,095
Operating Segments [Member] | Ethanol [Member]
Total Assets by Reportable Segments
Reportable segment assets	1,344	1,316
Operating Segments [Member] | VLP [Member]
Total Assets by Reportable Segments
Reportable segment assets	1,517	979
Corporate and Eliminations [Member]
Total Assets by Reportable Segments
Reportable segment assets	$ 6,915	$ 5,783