Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	$ 106	$ 107	$ 213	$ 224
Lease revenue – related parties	14	14
Total revenue	120	121	241	252
Related Parties
Disaggregation of Revenue [Line Items]
Lease revenue – related parties			28	28
Transportation Services | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	25	32	54	72
Transportation Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	41	51	96	101
Storage Services | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	2	2	4	4
Storage Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	2	2	4	4
Terminaling Services | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	30	11	42	23
Terminaling Services, Major Maintenance | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	4	0	4	0
Product Revenue | Third Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	0	3	0	4
Product Revenue | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	2	6	9	16
Transportation Services, Non-lease Service | Related Parties
Disaggregation of Revenue [Line Items]
Total Topic 606 revenue	$ 1	$ 2	$ 1	$ 2