Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Electric fuel and purchased power	$ 158	$ 103	$ 374	$ 263
Operating and maintenance expenses	83	83	171	155
Utilities Operating Expense, Depreciation and Amortization	115	136	227	235
Other income, net	3	4	4	5
Interest and Debt Expense	45	39	88	74
Income Tax Expense (Benefit)	(16)	(18)	(37)	(37)
Net income	101	89	160	146
Total revenues | Regulated Electric Segment
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	508	458	1,029	886
Electric fuel and purchased power	158	103	374	263
Operating and maintenance expenses	83	83	171	155
Utilities Operating Expense, Depreciation and Amortization	115	136	227	235
Other income, net	22	26	46	50
Interest and Debt Expense	45	39	88	74
Income Tax Expense (Benefit)	(16)	(18)	(37)	(37)
Net income	$ 101	$ 89	$ 160	$ 146