Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Electric fuel and purchased power	$ 208	$ 163	$ 582	$ 426
Operating and maintenance expenses	86	82	257	237
Utilities Operating Expense, Depreciation and Amortization	118	109	345	344
Other income, net	4	5	8	10
Interest and Debt Expense	45	40	133	114
Income Tax Expense (Benefit)	20	5	(17)	(32)
Net income	160	176	320	322
Total revenues | Regulated Electric Segment
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	655	594	1,684	1,480
Electric fuel and purchased power	208	163	582	426
Operating and maintenance expenses	86	82	257	237
Utilities Operating Expense, Depreciation and Amortization	118	109	345	344
Other income, net	18	19	64	69
Interest and Debt Expense	45	40	133	114
Income Tax Expense (Benefit)	20	5	(17)	(32)
Net income	$ 160	$ 176	$ 320	$ 322