CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2020	Dec. 31, 2019
Common unitholders' capital account, units outstanding (in shares)	393,289,537
Shell Pipeline Company L P
Preferred units, issued (in shares)	50,782,904	0
Preferred units, outstanding (in shares)	50,782,904	0
General partners' capital account, units issued (in units)	0	4,761,012
General partners' capital account, units outstanding (in units)	0	4,761,012
Common unitholders
Common unitholders' capital account, units issued (in shares)	123,832,233	123,832,233
Common unitholders' capital account, units outstanding (in shares)	123,832,233	123,832,233
Common unitholders | Shell Pipeline Company L P
Common unitholders' capital account, units issued (in shares)	269,457,304	109,457,304
Common unitholders' capital account, units outstanding (in shares)	269,457,304	109,457,304