Partners Capital Subsequent Events (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2013 Dividend Declared [Member]	Mar. 31, 2013 Issuance of Equity [Member]	Jul. 02, 2011 KinderHawk Field Services, LLC and EagleHawk Field Services, LLC [Member]
Subsequent Event [Line Items]
Per Unit Cash Distribution Declared (usd per share)		$ 4.98	$ 4.61	$ 4.40	$ 1.29
Fractional i-units to be issued						0.015676
Units to be issued (in shares)						1,804,595
Average ten day trading price (usd per share)						$ 82.294
Incentive Distribution, Distribution	$ 384	$ 1,322	$ 1,147	$ 848
Amount Of Incentive Distribution Waived As Result Of Kinderhawk Acquisition	7	27	28	11
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage							50.00%
Incentive distribution the general partner has agreed to waive for next twelve months	$ 4