CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income (loss)	[1]	$ (165)	$ 263	$ 263
Other comprehensive income (loss)
Change in fair value of cash flow hedges (Notes 12 and 20)		(2)	5	3	[1]
Reclassification to net income of gains and losses on cash flow hedges (Notes 12 and 20)		5		(2)	[1]
Amortization of realized loss on derivative instrument (Notes 12 and 20)		1	1	1	[1]
Other comprehensive income on equity investments (Note 12)		(1)	1
Comprehensive income (loss)		(162)	270	265	[1]
Comprehensive income attributable to non-controlling interests		17	11	16	[1]
Comprehensive income (loss) attributable to controlling interests		$ (179)	$ 259	$ 249	[1]

[1] Recast to consolidate PNGTS (Refer to Notes 2 and 8).