Segment Information, Total Assets by Reportable Segments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Total assets by reportable segments
Reportable segment assets	$ 45,550	$ 47,260
Refining [Member]
Total assets by reportable segments
Reportable segment assets	40,103	41,227
Ethanol [Member]
Total assets by reportable segments
Reportable segment assets	954	889
Corporate and Other [Member]
Total assets by reportable segments
Reportable segment assets	$ 4,493	$ 5,144