Revenue - Schedule of Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 951,712	$ 944,955
Wholesale Energy Sales
Disaggregation of Revenue [Line Items]
Total operating revenues	26,864	95,603
Transmission Services for Others
Disaggregation of Revenue [Line Items]
Total operating revenues	27,712	31,791
Other Sources
Disaggregation of Revenue [Line Items]
Total operating revenues	2,961	1,700
Residential | Retail Electric Service
Disaggregation of Revenue [Line Items]
Total operating revenues	432,692	409,724
Non-Residential | Retail Electric Service
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 461,483	$ 406,137