FINANCIAL CHARGES AND OTHER (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016		Sep. 30, 2017	Sep. 30, 2016
FINANCIAL CHARGES AND OTHER
Interest Expense	$ 23	$ 17		$ 59	$ 52
PNGTS' amortization of derivative loss on derivative instruments				1	1
Net realized loss related to the interest rate swaps		1			2
Other Income				(1)	(2)
Financial charges and other	$ 23	$ 18	[1]	$ 59	$ 53	[1]

[1] Recast to consolidate PNGTS for all periods presented (Refer to Notes 2 and 6).