Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Total Operating Revenues	$ 1,358,751	$ 1,308,994	$ 2,391,031	$ 2,260,706
Wholesale Energy Sales
Disaggregation of Revenue [Line Items]
Total Operating Revenues	17,893	10,261	42,717	37,125
Transmission Services for Others
Disaggregation of Revenue [Line Items]
Total Operating Revenues	31,996	27,541	57,543	55,253
Other Sources
Disaggregation of Revenue [Line Items]
Total Operating Revenues	3,158	3,163	11,287	6,124
Residential | Retail Electric Service
Disaggregation of Revenue [Line Items]
Total Operating Revenues	651,666	658,158	1,100,589	1,090,850
Non-Residential | Retail Electric Service
Disaggregation of Revenue [Line Items]
Total Operating Revenues	$ 654,038	$ 609,871	$ 1,178,895	$ 1,071,354