Revenue - Schedule of Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 1,768,801	$ 1,637,759	$ 4,029,507	$ 3,704,417
Wholesale Energy Sales
Disaggregation of Revenue [Line Items]
Total operating revenues	39,303	57,801	76,428	180,686
Transmission Services for Others
Disaggregation of Revenue [Line Items]
Total operating revenues	38,705	43,286	93,958	108,229
Other Sources
Disaggregation of Revenue [Line Items]
Total operating revenues	2,592	4,115	8,716	8,057
Residential | Retail Electric Service
Disaggregation of Revenue [Line Items]
Total operating revenues	966,557	883,393	2,057,407	1,835,432
Non-Residential | Retail Electric Service
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 721,644	$ 649,164	$ 1,792,998	$ 1,572,013