CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Operating Lease, Liability, Noncurrent	$ 5	$ 5
Operating Lease, Right-of-Use Asset	5	5
Current assets:
Cash and cash equivalents	0	0
Accounts receivable, net	47	45
Accounts receivable from related companies	8	9
Exchanges receivable	6	9
Inventories	86	61
Other current assets	6	7
Total current assets	153	131
Property, plant and equipment
Total property, plant and equipment	3,349	3,281
Accumulated depreciation	(717)	(607)
Property, Plant and Equipment, Net, Total	2,632	2,674
Other Assets, Noncurrent	169	159
Total assets	2,959	2,969
Current liabilities:
Accounts payable	4	6
Accounts payable to related companies	14	34
Exchanges payable	71	47
Other current liabilities	33	75
Total current liabilities	122	162
Long-term debt, less current maturities	245	247
Note payable to related company	550	732
Other non-current liabilities	243	221
Commitments and contingencies
Partners’ capital:
Partners’ capital	1,803	1,626
Accumulated other comprehensive loss	(9)	(24)
Total partners’ capital	1,794	1,602
Total liabilities and partners’ capital	$ 2,959	$ 2,969