PLANT, PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
PLANT, PROPERTY AND EQUIPMENT
Cost	$ 2,760	$ 2,705
Accumulated Depreciation	(811)	(737)
Net Book Value	1,949	1,968
Pipeline
PLANT, PROPERTY AND EQUIPMENT
Cost	2,086	2,038
Accumulated Depreciation	(638)	(574)
Net Book Value	1,448	1,464
Compression
PLANT, PROPERTY AND EQUIPMENT
Cost	516	514
Accumulated Depreciation	(134)	(126)
Net Book Value	382	388
Metering and other
PLANT, PROPERTY AND EQUIPMENT
Cost	156	145
Accumulated Depreciation	(39)	(37)
Net Book Value	117	108
Construction in progress
PLANT, PROPERTY AND EQUIPMENT
Cost	2	8
Net Book Value	$ 2	$ 8