Operating Segments (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)
Operating segment information
Operating segments number | segment			3
Revenues:
Revenues	$ 5,551	$ 11,127	$ 18,156	$ 34,005
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Equity earnings in unconsolidated entities	45	29	134	73
Segment profit	487	530	1,371	1,627
Maintenance capital	52	56	154	151
Transportation
Revenues:
Revenues	172	198	538	574
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Equity earnings in unconsolidated entities	45	29	134	73
Segment profit	254	231	681	658
Maintenance capital	34	35	101	111
Facilities
Revenues:
Revenues	132	141	393	443
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Segment profit	146	147	432	435
Maintenance capital	16	19	48	34
Supply and Logistics
Revenues:
Revenues	5,247	10,788	17,225	32,988
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Segment profit	87	152	258	534
Maintenance capital	2	2	5	6
Interest expense related to hedged inventory purchases	1	4	4	11
Operating Segments
Revenues:
Revenues	5,918	11,498	19,230	35,101
Operating Segments | Transportation
Revenues:
Revenues	401	424	1,203	1,222
Operating Segments | Facilities
Revenues:
Revenues	263	281	789	858
Operating Segments | Supply and Logistics
Revenues:
Revenues	5,254	10,793	17,238	33,021
Intersegment
Revenues:
Revenues	(367)	(371)	(1,074)	(1,096)
Intersegment | Transportation
Revenues:
Revenues	(229)	(226)	(665)	(648)
Intersegment | Facilities
Revenues:
Revenues	(131)	(140)	(396)	(415)
Intersegment | Supply and Logistics
Revenues:
Revenues	$ (7)	$ (5)	$ (13)	$ (33)