CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2017	Sep. 30, 2016
OPERATING REVENUES:
Transportation and storage of natural gas	$ 104	$ 115		$ 327	$ 370
Other	6	5		15	15
Total operating revenues	110	120		342	385
OPERATING EXPENSES:
Cost of natural gas and other energy	0	0		2	2
Operating and maintenance	52	53		149	155
General and administrative	10	11		27	29
Depreciation and amortization	32	33		95	98
Total operating expenses	94	97		273	284
OPERATING INCOME	16	23		69	101
OTHER INCOME (EXPENSE):
Interest expense, net	(11)	(12)		(34)	(37)
Interest income - affiliates	1	9		9	23
Other, net	0	0		1	0
INCOME BEFORE INCOME TAX EXPENSE	6	20		45	87
Income tax expense	2	7		19	28
NET INCOME	4	13		26	59
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	9	13		31	59
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	$ 5	0		5	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest