Equity - Schedule of Distributions Declared and/or Paid (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended									6 Months Ended
	Jun. 09, 2016	Mar. 29, 2016	Jun. 30, 2017		Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016		Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2017		Jun. 30, 2016	[2]
Distribution Made To Limited Partner [Line Items]
Aggregate percentage of general partner interest												2.00%
Distributions declared and/or paid			$ 68.2		$ 63.6	$ 58.6	$ 53.9	$ 49.0		$ 41.7	$ 35.3
Distributions paid per limited partner unit (in dollars per unit)			$ 0.30410	[1]	$ 0.291	$ 0.27700	$ 0.26375	$ 0.2500	[2]	$ 0.2350	$ 0.2200	$ 0.5951	[1]	$ 0.4850
Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid			$ 0.0		$ 0.0	$ 18.7	$ 17.8	$ 16.9		$ 15.8	$ 14.8
Common Units | General Public
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid			26.9		25.7	24.5	23.3	22.0		17.9	13.9
Common Units | Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid			$ 27.0		25.9	5.9	5.7	5.4		$ 5.1	4.7
General Partner
Distribution Made To Limited Partner [Line Items]
Aggregate percentage of general partner interest	2.00%	2.00%	2.00%							2.00%		2.00%
Distributions declared and/or paid			$ 1.4		1.3	1.2	1.1	1.0		$ 0.9	0.7
General Partner | IDR's
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid			$ 12.9		$ 10.7	$ 8.3	$ 6.0	$ 3.7		$ 2.0	$ 1.2

[1] The 2017 financial information reflects adjustments for the acquisition of the Shell Delta, Na Kika and Refinery Gas Pipeline Operations from January 1, 2017 through May 9, 2017.

[2] Prior period financial information has been retrospectively adjusted for the acquisition of the Shell Delta, Na Kika and Refinery Gas Pipeline Operations.