FINANCIAL CHARGES AND OTHER (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
FINANCIAL CHARGES AND OTHER
Interest Expense	$ 19	$ 16		$ 36	$ 35
PNGTS' amortization of derivative loss on derivative instruments	1	1		1	1
Net realized loss related to the interest rate swaps		1			1
Other Income	(1)	(1)		(1)	(2)
Financial charges and other	$ 19	$ 17	[1]	$ 36	$ 35	[1]

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