CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2018	Dec. 31, 2017
Shell Pipeline Company L P
General partners' capital account, units issued (in units)	4,567,588	3,832,293
General partners' capital account, units outstanding (in units)	4,567,588	3,832,293
Common unitholders
Limited partners' capital account, units outstanding (in units)	223,811,781
Common unitholders | General Public
Limited partners' capital account, units issued (in units)	123,832,233	98,832,233
Limited partners' capital account, units outstanding (in units)	123,832,233	98,832,233
Common unitholders | Shell Pipeline Company L P
Limited partners' capital account, units issued (in units)	99,979,548	88,950,136
Limited partners' capital account, units outstanding (in units)	99,979,548	88,950,136