Partners Capital Subsequent Events (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		0 Months Ended	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Jul. 18, 2012 Dividend Declared [Member]	Mar. 31, 2013 Issuance of Equity [Member]
Subsequent Event [Line Items]
Proceeds on sales of units	$ 385	$ 124
Per Unit Cash Distribution Declared (usd per share)	$ 1.30	$ 1.20	$ 1.30
Fractional i-units to be issued				0.014770
Units to be issued (in shares)				1,726,952
Average ten day trading price (usd per share)				$ 88.015