Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense expressed as a percentage of average depreciable property	3.80%	3.40%	3.40%
Accounts and Financing Receivable, after Allowance for Credit Loss, Current and Noncurrent [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 10	$ 12
Alternative Revenue Programs [Abstract]
maximum number of months following end of annual period	24 months
Public Utilities, Inventory [Line Items]
Inventory	$ 84	$ 71
maximum number of months following end of annual period	24 months
Depreciation expense expressed as a percentage of average depreciable property	3.80%	3.40%	3.40%
Supplies
Public Utilities, Inventory [Line Items]
Inventory	$ 74	$ 60
Fuel
Public Utilities, Inventory [Line Items]
Inventory	$ 10	$ 11