DERIVATIVES (Additional Cash Collateral The Utility Would Be Required To Post If Its Credit Risk-Related Contingency Features Were Triggered) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives in a liability position with credit risk-related contingencies that are not fully collateralized	$ (1)	$ (1)
Related derivatives in an asset position	0	0
Collateral posting in the normal course of business related to these derivatives	0	0
Net position of derivative contracts/additional collateral posting requirements	$ (1)	$ (1)