Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified			0 Months Ended	3 Months Ended		0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Apr. 29, 2011 Rainbow pipeline bbl	Mar. 31, 2013 Rainbow pipeline	Feb. 26, 2013 Rainbow pipeline item	Jun. 07, 2012 Rangeland Pipeline Release bbl	Mar. 31, 2013 Rangeland Pipeline Release charge	Feb. 05, 2013 Bay Springs Pipeline bbl	Mar. 31, 2013 Minimum	Mar. 31, 2013 Maximum	Mar. 31, 2013 Maximum Bay Springs Pipeline
Loss Contingencies
Estimated size of release (in barrels)			28,000			3,000		125
Total estimated cost to clean up and remediate the site, before insurance recoveries				$ 70			$ 45				$ 10
Charges issued							0
Penalty or fines paid							0
Number of enforcement actions					4
Environmental
Estimated environmental reserve	101	96
Reserve for environmental liabilities, short-term	16	13
Reserve for environmental liabilities, long-term	85	83
Probable recoveries from insurers and third parties recorded as a receivable	$ 16	$ 42
Actual cash expenditures for environmental liabilities, period paid									3 years	5 years