Segment Information Segment Information - Total Assets By Reportable Segment (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 29,376	$ 28,385
Operating Segments | Refining & Marketing
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	20,708	19,573
Operating Segments | Speedway
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,185	2,064
Operating Segments | Pipeline Transportation
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,135	1,947
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 4,348	$ 4,801