Segment Information, Total Assets by Reportable Segments (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Total assets by reportable segments
Reportable segment assets	$ 44,343	$ 45,550
Refining [Member]
Total assets by reportable segments
Reportable segment assets	38,142	40,103
Ethanol [Member]
Total assets by reportable segments
Reportable segment assets	1,016	954
Corporate [Member]
Total assets by reportable segments
Reportable segment assets	$ 5,185	$ 4,493