STOCKHOLDER'S EQUITY (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2018
Balance at the beginning of period		$ 0	$ (3)	$ 2	$ 4	$ 0
Reclassification of net loss relating to interest rate cash flow hedges from AOCI to earnings, Tax		(1)	0	(1)	(1)
Reclassification of net loss relating to interest rate cash flow hedges from AOCI to interest expense, net of tax	[1]	1	0	1	1
Other Comprehensive Income (Loss), Gain (Loss) on Derivatives Qualifying as Hedges, Tax		(1)	0	0	6
Other Comprehensive Income (Loss), Gain (Loss) on Derivatives Qualifying as Hedges, Net of Tax		2	0	0	(8)
Other Comprehensive Income (Loss), Net of Tax		3	0	1	(7)
Balance at the end of period (b)	[2]	3	(3)	3	(3)
Unrealized gains on available-for-sale securities, net of tax		$ 1	$ 1	$ 1	$ 1
Expectation
Reclassification of net loss relating to interest rate cash flow hedges from AOCI to earnings, Tax						1
Portion expected to be reclassified from AOCI to interest expense during the next twelve months						$ 2

[1] The reclassification of net loss relating to interest rate cash flow hedges is reported in interest expense on a pre-tax basis.

[2] Includes unrealized gains on available-for-sale securities, net of tax, of less than $1 million for the three and nine months ended September 30, 2017 and 2016.