Property, Plant, and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Less accumulated depreciation	$ (8,020,000)	$ (6,657,000)
Finance lease right-of-use assets (net of accumulated amortization)	153,000	160,000
Nuclear fuel (net of accumulated amortization of $409 million and $120 million)	1,434,000	379,000
Property, plant, and equipment — net	18,173,000	12,432,000
Depreciable Property, Plant and Equipment
Property, Plant and Equipment [Line Items]
Total	23,546,000	18,028,000
Property, plant, and equipment — net	15,526,000	11,371,000
Power generation and structures
Property, Plant and Equipment [Line Items]
Total	22,783,000	17,297,000
Land
Property, Plant and Equipment [Line Items]
Total	603,000	572,000
Office and other equipment
Property, Plant and Equipment [Line Items]
Total	160,000	159,000
Construction work in progress
Property, Plant and Equipment [Line Items]
Total	1,060,000	522,000
Nuclear Fuel
Property, Plant and Equipment [Line Items]
Less accumulated depreciation	$ (409,000)	$ (120,000)