(Deficit) Equity - Schedule of Number of Units Outstanding (Details) - shares		9 Months Ended
	Feb. 06, 2018	Sep. 30, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)		228,379,369
Units issued in connection with equity offerings (in shares)		9,671,180
Ending balance (in shares)		238,050,549
General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)		4,567,588
Units issued in connection with equity offerings (in shares)	510,204	193,424
Ending balance (in shares)		4,761,012
General Public | Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)		123,832,233
Units issued in connection with equity offerings (in shares)	25,000,000	0
Ending balance (in shares)		123,832,233
Shell Pipeline Company L P | Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)		99,979,548
Units issued in connection with equity offerings (in shares)		9,477,756
Ending balance (in shares)		109,457,304