Partners' Capital and Distributions (Details) (Class A Shares, USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended	3 Months Ended	0 Months Ended
	May 15, 2015	Mar. 31, 2015	Feb. 13, 2015
First quarter 2015 distribution | Subsequent Event
Partners Capital and Distribution
Date Declared		Apr. 07, 2015
Distribution Date		May 15, 2015
Distributions to Class A shareholders	$ 50
Distribution per Class A share	$ 0.222
Shareholders of record, date		May 01, 2015
Fourth quarter 2014 distribution
Partners Capital and Distribution
Date Declared		Jan. 08, 2015
Distribution Date		Feb. 13, 2015
Distributions to Class A shareholders			$ 42
Distribution per Class A share			$ 0.203