GENERAL AND BASIS OF PRESENTATION - Principal customers, total revenues (Details) - Revenue Benchmark - Customer Concentration Risk	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Southern California Public Power Authority (“SCPPA”)
Concentration Risk [Line Items]
Concentration risk (in percentage)	15.10%	17.90%	17.90%	20.90%
Sierra Pacific Power Company and Nevada Power Company
Concentration Risk [Line Items]
Concentration risk (in percentage)	12.10%	13.50%	13.70%	15.00%
Kenya Power and Lighting Co. Ltd. ("KPLC")
Concentration Risk [Line Items]
Concentration risk (in percentage)	11.90%	13.50%	12.10%	12.90%