Equity - Schedule of Number of Units Outstanding (Details) - shares					3 Months Ended			9 Months Ended
	Sep. 15, 2017	Jun. 09, 2016	May 23, 2016	Mar. 29, 2016	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2016	Sep. 30, 2017
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)								180,936,167
Expiration of subordination period (in shares)								0
Partners' capital account, units, sold in private placement								5,402,985
Units issued in connection with ATM program (in shares)								5,275,510
Ending balance (in shares)					191,614,662			191,614,662
General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)								3,618,723
Expiration of subordination period (in shares)								0
Partners' capital account, units, sold in private placement					106,122	1,938	15,307	108,060
Units issued in connection with ATM program (in shares)	105,510	32,143		258,163				105,510
Ending balance (in shares)					3,832,293			3,832,293
General Public | Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)								88,367,308
Expiration of subordination period (in shares)								0
Partners' capital account, units, sold in private placement					5,200,000	94,925	750,000	5,294,925
Units issued in connection with ATM program (in shares)	5,170,000		1,575,000	12,650,000				5,170,000
Ending balance (in shares)					98,832,233			98,832,233
Shell Pipeline Company L P | Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)								21,475,068
Expiration of subordination period (in shares)								67,475,068
Partners' capital account, units, sold in private placement								0
Units issued in connection with ATM program (in shares)								0
Ending balance (in shares)					88,950,136			88,950,136
Shell Pipeline Company L P | Subordinated Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)								67,475,068
Expiration of subordination period (in shares)								(67,475,068)
Partners' capital account, units, sold in private placement								0
Units issued in connection with ATM program (in shares)								0
Ending balance (in shares)					0			0