Equity - Schedule of Distributions Declared and/or Paid (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended								9 Months Ended			14 Months Ended
	Jun. 09, 2016	May 23, 2016	Mar. 29, 2016	May 18, 2015	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015		Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	[1]	Dec. 31, 2015
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid					$ 53.9	$ 49.0	$ 41.7	$ 35.3	$ 30.3	$ 27.7		$ 24.1				$ 14.4
Distributions paid per limited partner unit (in dollars per unit)					$ 0.26375	$ 0.2500	$ 0.2350	$ 0.2200	$ 0.2050	$ 0.1900	[1]	$ 0.1750	$ 0.7488	$ 0.57		$ 0.1042
Aggregate percentage of general partner interest													2.00%
Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid					$ 17.8	$ 16.9	$ 15.8	$ 14.9	$ 13.9	$ 12.8		$ 11.8				$ 7.1
Common Units | General Public
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid					23.3	22.0	17.9	13.8	11.0	10.2		8.0				4.8
Aggregate percentage of general partner interest	2.00%	2.00%
Common Units | Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid					5.7	5.4	5.1	4.7	4.4	4.1		3.8				2.2
General Partner
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid					1.1	1.0	$ 0.9	0.7	0.6	0.5		0.5				0.3
Aggregate percentage of general partner interest			2.00%	2.00%			2.00%						2.00%
General Partner | General Partner Incentive
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid					$ 6.0	$ 3.7	$ 2.0	$ 1.2	$ 0.4	$ 0.1		$ 0.0				$ 0.0

[1] (1) The 2015 financial information has been retrospectively adjusted for the acquisition of the Shell Auger and Lockport Operations.