Equity - Schedule of Distributions Declared and/or Paid (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Mar. 29, 2016	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid		$ 63.6	$ 58.6	$ 53.9	$ 49.0	$ 41.7	$ 35.3
Distributions paid per limited partner unit (in dollars per unit)		$ 0.291	$ 0.27700	$ 0.26375	$ 0.2500	$ 0.2350	$ 0.2200
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		$ 0.0	$ 18.7	$ 17.8	$ 16.9	$ 15.8	$ 14.9
Common Units | General Public
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid		25.7	24.5	23.3	22.0	17.9	13.8
Common Units | Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid		25.9	5.9	5.7	5.4	5.1	4.7
General Partner
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid		$ 1.3	1.2	1.1	1.0	$ 0.9	0.7
Aggregate percentage of general partner interest	2.00%	2.00%				2.00%
General Partner | IDR's
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid		$ 10.7	$ 8.3	$ 6.0	$ 3.7	$ 2.0	$ 1.2