Segment Information, Total Assets by Reportable Segments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Total assets by reportable segments
Reportable segment assets	$ 47,260	$ 44,477
Refining [Member]
Total assets by reportable segments
Reportable segment assets	40,834	38,858
Retail [Member]
Total assets by reportable segments
Reportable segment assets	0	2,043
Ethanol [Member]
Total assets by reportable segments
Reportable segment assets	889	929
Corporate and Other [Member]
Total assets by reportable segments
Reportable segment assets	$ 5,537	$ 2,647