Revenues and Segment Information, Assets (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Total Assets by Reportable Segment
Reportable segment assets	$ 49,376	$ 50,158
Corporate, Non-Segment [Member]
Total Assets by Reportable Segment
Reportable segment assets	5,777	6,915
Refining [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	40,699	40,382
Ethanol [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	1,355	1,344
VLP [Member] | Operating Segments [Member]
Total Assets by Reportable Segment
Reportable segment assets	$ 1,545	$ 1,517