Partners' Capital and Distributions (Details) (Class A Shares, USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended	9 Months Ended	0 Months Ended	9 Months Ended	0 Months Ended	9 Months Ended	0 Months Ended	9 Months Ended
	Aug. 14, 2014 Second Quarter Distribution	Sep. 30, 2014 Second Quarter Distribution	May 15, 2014 First Quarter Distribution	Sep. 30, 2014 First Quarter Distribution	Feb. 14, 2014 Fourth quarter distribution	Sep. 30, 2014 Fourth quarter distribution	Nov. 14, 2014 Third quarter distribution Subsequent Event	Sep. 30, 2014 Third quarter distribution Subsequent Event
Partners Capital and Distribution
Date Declared		Jul. 08, 2014		Apr. 07, 2014		Jan. 09, 2014		Oct. 08, 2014
Distribution Date		Aug. 14, 2014		May 15, 2014		Feb. 14, 2014		Nov. 14, 2014
Distributions to Class A shareholders	$ 25		$ 23		$ 17		$ 26
Distribution per Class A share (in dollars per share)	$ 0.18340		$ 0.17055		$ 0.12505		$ 0.19075
Shareholders of record, date								Oct. 31, 2014