Segment Information (Total Assets By Reportable Segment) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	$ 28,385	$ 27,223
Operating Segments [Member] | Refining & Marketing [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	19,573	17,052
Operating Segments [Member] | Speedway [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	2,064	1,947
Operating Segments [Member] | Pipeline Transportation [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	1,947	1,950
Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	$ 4,801	$ 6,274