OTHER LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
OTHER LIABILITIES
Regulatory liabilities	$ 26	$ 25
Other liabilities	3	3
Other liabilities, total	$ 29	$ 28	[1]

[1] Recast to consolidate PNGTS (Refer to Notes 2 and 7).