Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Electric fuel and purchased power	$ 216	$ 160
Operating and maintenance expenses	88	72
Utilities Operating Expense, Depreciation and Amortization	112	99
Other income, net	1	1
Interest and Debt Expense	43	35
Income Tax Expense (Benefit)	(21)	(19)
Net income	59	57
Total revenues | Regulated Electric Segment
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	521	428
Electric fuel and purchased power	216	160
Operating and maintenance expenses	88	72
Utilities Operating Expense, Depreciation and Amortization	112	99
Other income, net	24	24
Interest and Debt Expense	43	35
Income Tax Expense (Benefit)	(21)	(19)
Net income	$ 59	$ 57