Summary of Significant Accounting Policies - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Utility Plant and Depreciation [Line Items]
Net	$ 15,803,127	$ 14,522,268
Construction work in progress	1,724,004	1,882,791
Intangible assets, net of accumulated amortization	267,110	258,880
Nuclear fuel, net of accumulated amortization	99,490	100,119
Total property, plant and equipment	17,980,157	16,854,354
Electric Service
Utility Plant and Depreciation [Line Items]
Generation	10,446,291	9,563,145
Transmission	3,773,253	3,589,456
Distribution	8,448,293	7,951,867
General plant	1,543,330	1,347,678
Plant in service and held for future use	24,211,167	22,452,146
Accumulated depreciation and amortization	(8,408,040)	(7,929,878)
Net	15,803,127	14,522,268
Construction work in progress	1,724,004	1,882,791
Intangible assets, net of accumulated amortization	267,110	258,880
Nuclear fuel, net of accumulated amortization	99,490	100,119
Total property, plant and equipment	17,980,157	16,854,354
Electric Service | Variable Interest Entity
Utility Plant and Depreciation [Line Items]
Total property, plant and equipment	$ 86,426	$ 90,296