(Deficit) Equity - Schedule of Distributions Declared and/or Paid (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended													12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distribution Made To Limited Partner [Line Items]
Distribution to holders of incentive distribution rights waived		$ 16	$ 17	$ 17										$ 50
Distributions declared and/or paid	$ 162	$ 140	$ 131	$ 119	$ 129	$ 121	$ 113	$ 106	$ 83	$ 77	$ 68	$ 64	$ 59
Distributions per Limited Partner unit (in dollars per share)	$ 0.46000	$ 0.44500	$ 0.43000	$ 0.41500	$ 0.40000	$ 0.38200	$ 0.36500	$ 0.34800	$ 0.33300	$ 0.31800	$ 0.30410	$ 0.29100	$ 0.27700	$ 1.7500	$ 1.4950	$ 1.2461
Shell Midstream Partners L.P.
Distribution Made To Limited Partner [Line Items]
Aggregate percentage of interest														200.00%
Common units - SPLC | General Public
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid	$ 57	$ 56	$ 53	$ 51	$ 49	$ 47	$ 46	$ 43	$ 33	$ 31	$ 27	$ 26	$ 25
Common units - SPLC | Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid	50	48	47	42	40	38	36	35	30	28	27	26	6
Subordinated Units | Shell Pipeline Company L P
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid	0	0	0	0	0	0	0	0	0	0	0	0	18
General Partner
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid	3	3	3	3	3	3	2	2	2	2	1	1	1
General Partner | General Partner IDR's
Distribution Made To Limited Partner [Line Items]
Distributions declared and/or paid	$ 52	$ 33	$ 28	$ 23	$ 37	$ 33	$ 29	$ 26	$ 18	$ 16	$ 13	$ 11	$ 9