Other Income Tax Matters (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Tax [Line Items]
Federal tax credit carryforwards		$ 295	$ 292
State NOL carryforwards		$ 1	$ 2
Federal statutory rate		21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	[1]	3.20%	1.50%	2.60%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	[2]	(32.60%)	(34.30%)	(33.50%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent		(0.40%)	0.10%	0.20%
AFUDC equity		(11.30%)	(16.90%)	(13.30%)
Total income tax benefit		$ (40)	$ (57)	$ (45)
Deferred tax expense (benefit) excluding items below		48	143	(117)
Adjustments to deferred income taxes for wind production tax credit (a)		(114)	(226)	0
Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities		(14)	(19)	(16)
Income Tax Expense (Benefit), Intraperiod Tax Allocation		(1)	(1)	0
Total deferred tax assets		(81)	(103)	(133)
income tax expense [Member]
Income Tax [Line Items]
Current federal tax expense		30	42	76
Current state tax expense		9	4	12
Deferred federal tax benefit		(86)	(105)	(132)
Deferred state tax expense (benefit)		5	2	(1)
Deferred change in unrecognized tax expense		0	0	0
Total income tax benefit		(40)	(57)	(45)
Current Change In Unrecognized Tax Expense Benefit		2	0	$ 0
Net Deferred Tax Liablility [Member]
Income Tax [Line Items]
Federal tax credit carryforwards		295	292
Operating lease assets		76	83
Regulatory assets		38	53
Deferred tax liability - Pension expense		33	33
Total deferred tax liabilities		1,288	1,260
Regulatory liabilities		81	90
other employee benefits		6	5
Deferred Fuel Cost		3	10
Other		14	15
Operating lease liabilities		76	83
Total deferred tax assets		(475)	(495)
Net deferred tax liability		813	765
Differences between book and tax bases of property		1,139	1,089
Net Deferred Tax Liability
Income Tax [Line Items]
Deferred Tax Assets, Tax Deferred Expense, Other		$ 2	$ 2

[1] State and local income taxes are primarily made up of the following jurisdictions: Texas

[2] Wind PTCs (net of transfer discounts) are generally credited to customers (reduction to revenue) and do not materially impact earnings.