Partners' Capital (Schedule of Partners' Capital Account, Distriubtions) (Details) - USD ($) $ / shares in Units, $ in Millions													9 Months Ended
	Aug. 14, 2017	Aug. 07, 2017	May 15, 2017	May 08, 2017	Feb. 14, 2017	Feb. 07, 2017	May 13, 2016	May 06, 2016	Feb. 12, 2016	Feb. 05, 2016	Aug. 14, 2015	Aug. 07, 2015	Sep. 30, 2017	Sep. 30, 2016
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Date of Record		Aug. 07, 2017		May 08, 2017		Feb. 07, 2017		May 06, 2016		Feb. 05, 2016		Aug. 05, 2016
Distribution Made to Limited Partner, Distribution Date	Aug. 14, 2017		May 15, 2017		Feb. 14, 2017		May 13, 2016		Feb. 12, 2016		Aug. 12, 2016
Distribution Made to Member or Limited Partner, Distributions Paid, Per Unit	$ 0.60		$ 0.60		$ 0.6		$ 0.60		$ 1.375		$ 0.60
Distribution Made to Limited Partner, Cash Distributions Paid	$ 41.8		$ 41.8		$ 41.8		$ 41.4		$ 95.6		$ 41.4		$ 125.4	$ 178.4