Summary of Significant Accounting Policies - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Utility Plant and Depreciation [Line Items]
Net	$ 14,522,268	$ 14,184,058
Construction work in progress	1,882,791	1,329,478
Intangible assets, net of accumulated amortization	258,880	273,693
Nuclear fuel, net of accumulated amortization	100,119	106,039
Total property, plant and equipment	16,854,354	15,987,434
Electric Service
Utility Plant and Depreciation [Line Items]
Generation	9,563,145	9,480,572
Transmission	3,589,456	3,402,016
Distribution	7,951,867	7,520,016
General plant	1,347,678	1,286,057
Plant in service and held for future use	22,452,146	21,688,661
Accumulated depreciation and amortization	(7,929,878)	(7,504,603)
Net	14,522,268	14,184,058
Construction work in progress	1,882,791	1,329,478
Intangible assets, net of accumulated amortization	258,880	273,693
Nuclear fuel, net of accumulated amortization	100,119	106,039
Total property, plant and equipment	16,854,354	15,987,434
Electric Service | Variable Interest Entity
Utility Plant and Depreciation [Line Items]
Total property, plant and equipment	$ 90,296	$ 94,166