REVENUE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 1,480,000	$ 1,324,000	$ 1,343,000
Alternative Revenues	12,000	48,000	35,000
Other	101,000	53,000	40,000
Total Operating Revenues	1,592,586	1,424,741	1,418,338
Retail
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,088,000	1,039,000	972,000
Wholesale
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	278,000	190,000	247,000
Other Services
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 114,000	$ 95,000	$ 124,000
Lost Fixed Cost Recovery Mechanism
Disaggregation of Revenue [Line Items]
Cap on increase in lost fixed cost recovery rate (percentage)	2.00%