Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	$ 117	$ 86
Lease revenue	14	14
Total revenue	131	100
Transportation Services | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	40	32
Transportation Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	50	31
Storage Services | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	2	3
Storage Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	2	1
Terminaling Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	12	11
Product Revenue | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	1	0
Product Revenue | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	10	$ 8
Transportation Services, Non-lease Service | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	$ 1