Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital leases and other	$ 0	$ 0	$ 2
Predecessors’ net liabilities not assumed by Andeavor Logistics	13	0	22
Receivable from affiliate for capital expenditures	26	4	4
Accounts Payable [Member]
Capital Expenditures Incurred but Not yet Paid	105	50	30
Affiliate Payable [Member]
Capital Expenditures Incurred but Not yet Paid	$ 0	$ 0	$ 8