Operating Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 segment	Jun. 30, 2011
Operating Segments
Operating segments number			3
Revenues:
External Customers	$ 9,786	$ 8,859	$ 19,004	$ 16,553
Intersegment	304	181	516	358
Total revenues of reportable segments	10,090	9,040	19,520	16,911
Equity earnings in unconsolidated entities	9	4	16	5
Segment profit	557	365	938	714
Maintenance capital	40	27	76	52
Transportation
Revenues:
External Customers	158	147	307	288
Intersegment	203	143	371	276
Total revenues of reportable segments	361	290	678	564
Equity earnings in unconsolidated entities	9	4	16	5
Segment profit	169	128	332	265
Maintenance capital	27	17	52	35
Facilities
Revenues:
External Customers	186	126	378	244
Intersegment	101	38	145	81
Total revenues of reportable segments	287	164	523	325
Segment profit	114	86	204	164
Maintenance capital	10	7	17	10
Supply and Logistics
Revenues:
External Customers	9,442	8,586	18,319	16,021
Intersegment				1
Total revenues of reportable segments	9,442	8,586	18,319	16,022
Segment profit	274	151	402	285
Maintenance capital	3	3	7	7
Interest expense related to hedged inventory purchases	$ 4	$ 7	$ 6	$ 12