FAIR VALUE MEASUREMENTS AND DERIVATIVE INSTRUMENTS (Financial Instruments Measured at Fair Value on a Recurring Basis) (Details) - Fair Value, Measurements, Recurring - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Assets
Restricted Cash	$ 23,000,000	$ 21,000,000
Energy Derivative Contract, Regulatory Recovery	30,000,000	14,000,000
Energy Derivative Contract, No Regulatory Recovery	4,000,000	3,000,000
Total Assets	57,000,000	38,000,000
Liabilities
Energy Derivative Contracts, Regulatory Recovery	(20,000,000)	(66,000,000)
Total Liabilities	(20,000,000)	(66,000,000)
Total Assets (Liabilities), Net	37,000,000	(28,000,000)
Level 1
Assets
Restricted Cash	23,000,000	21,000,000
Energy Derivative Contract, Regulatory Recovery	0	0
Energy Derivative Contract, No Regulatory Recovery	0	0
Total Assets	23,000,000	21,000,000
Liabilities
Energy Derivative Contracts, Regulatory Recovery	0	0
Total Liabilities	0	0
Total Assets (Liabilities), Net	23,000,000	21,000,000
Level 2
Assets
Restricted Cash	0	0
Energy Derivative Contract, Regulatory Recovery	30,000,000	14,000,000
Energy Derivative Contract, No Regulatory Recovery	4,000,000	3,000,000
Total Assets	34,000,000	17,000,000
Liabilities
Energy Derivative Contracts, Regulatory Recovery	(20,000,000)	(66,000,000)
Total Liabilities	(20,000,000)	(66,000,000)
Total Assets (Liabilities), Net	14,000,000	$ (49,000,000)
Level 3
Liabilities
Total Assets (Liabilities), Net	$ 0