Related Party Transactions - Schedule of Reimbursement from Parent (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shell Pipeline Company L P
Related Party Transaction [Line Items]
Cash received		$ 19	$ 12	$ 16
Reimbursement related to cost and expenses for maintenance projects		19	12	16
Zydeco Pipeline Company LLC (“Zydeco”)
Related Party Transaction [Line Items]
Reimbursement related to cost and expenses for maintenance projects		$ 10	$ 12	14
Refinery Gas Pipeline
Related Party Transaction [Line Items]
Reimbursement related to cost and expenses for maintenance projects				$ 2
Mars | Shell Pipeline Company L P
Related Party Transaction [Line Items]
Cash received	$ 9