Related Party Transactions - Reimbursements from Our General Partner (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Related Party Transaction [Line Items]
Changes in receivable from Parent	$ 0	$ 4
Reimbursement of cost and expenses	7	4
Contributions from Parent	7	5
Shell Pipeline Company L P
Related Party Transaction [Line Items]
Cash received	7	1
Changes in receivable from Parent	0	3
Total reimbursements	$ 7	4
Contributions from Parent		$ 1