EMPLOYEE BENEFIT PLANS (Changes in Regulatory Assets and Accumulated Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits | Regulatory Asset
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Current Year Actuarial (Gain) Loss	$ 12	$ 5	$ 15
Amortization of Net Loss	(7)	(7)	(7)
Prior Service Credit	0	0	0
Total Recognized (Gain) Loss	5	(2)	8
Pension Benefits | Accumulated Other Comprehensive Loss
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Current Year Actuarial (Gain) Loss	(1)	3	1
Amortization of Net Loss	0	0	0
Prior Service Credit	(1)	0	0
Total Recognized (Gain) Loss	(2)	3	1
Other Postretirement Benefits | Regulatory Asset
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Current Year Actuarial (Gain) Loss	(6)	(1)	0
Amortization of Net Loss	0	0	0
Prior Service Credit	(2)	0	0
Total Recognized (Gain) Loss	$ (8)	$ (1)	$ 0