GENERAL AND BASIS OF PRESENTATION - Principal customers, total revenues (Details) - Revenue Benchmark - Customer Concentration Risk	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Southern California Public Power Authority (“SCPPA”)
Concentration Risk [Line Items]
Concentration risk (in percentage)	17.00%	19.70%	19.50%	22.30%
Sierra Pacific Power Company and Nevada Power Company
Concentration Risk [Line Items]
Concentration risk (in percentage)	12.90%	14.70%	14.50%	15.80%
Kenya Power and Lighting Co. Ltd. ("KPLC")
Concentration Risk [Line Items]
Concentration risk (in percentage)	12.50%	13.10%	12.30%	12.70%