EMPLOYEE BENEFIT PLANS (Changes in Regulatory Assets and Accumulated Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits | Regulatory Asset
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Current Year Actuarial (Gain) Loss	$ 16	$ 12	$ 5
Amortization of Net Loss	(8)	(7)	(7)
Prior Service Credit (Cost)	0	0	0
Total Recognized (Gain) Loss	8	5	(2)
Pension Benefits | AOCI
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Current Year Actuarial (Gain) Loss	4	(1)	3
Amortization of Net Loss	(1)	0	0
Prior Service Credit (Cost)	1	(1)	0
Total Recognized (Gain) Loss	4	(2)	3
Other Postretirement Benefits | Regulatory Asset
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Current Year Actuarial (Gain) Loss	1	(6)	(1)
Amortization of Net Loss	0	0	0
Prior Service Credit (Cost)	0	(2)	0
Total Recognized (Gain) Loss	$ 1	$ (8)	$ (1)