CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2017	Dec. 31, 2016
Shell Pipeline Company L P
General partners' capital account, units issued (in units)	3,832,293	3,618,723
General partners' capital account, units outstanding (in units)	3,832,293	3,618,723
Common unitholders
Limited partners' capital account, units outstanding (in units)	187,782,369
Common unitholders | General Public
Limited partners' capital account, units issued (in units)	98,832,233	88,367,308
Limited partners' capital account, units outstanding (in units)	98,832,233	88,367,308
Common unitholders | Shell Pipeline Company L P
Limited partners' capital account, units issued (in units)	88,950,136	21,475,068
Limited partners' capital account, units outstanding (in units)	88,950,136	21,475,068
Subordinated Units | Shell Pipeline Company L P
Limited partners' capital account, units issued (in units)	0	67,475,068
Limited partners' capital account, units outstanding (in units)	0	67,475,068