v3.25.1
Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($)
$ in Thousands
Mar. 31, 2025
Dec. 31, 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets $ 308,857 $ 301,513
Total financial liabilities 572 26,753
Nuclear Decommissioning Trust [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [1] 96,704 93,648
Nuclear Decommissioning Trust - Net Asset Value [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [1],[2] 192,120 198,993
Unrestricted Investment And Other [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [3] 76 108
Derivatives - Gas And Power [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [4] 19,957 8,764
Total financial liabilities [4] 572 26,753
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets 116,342 93,648
Total financial liabilities 0 26,054
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Nuclear Decommissioning Trust [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [1] 96,704 93,648
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Derivatives - Gas And Power [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [4] 19,638  
Total financial liabilities [4] 0 26,054
Significant Other Observable Inputs (Level 2) [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets 395 6,556
Total financial liabilities 565 699
Significant Other Observable Inputs (Level 2) [Member] | Unrestricted Investment And Other [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [3] 76 108
Significant Other Observable Inputs (Level 2) [Member] | Derivatives - Gas And Power [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [4] 319 6,448
Total financial liabilities [4] 565 699
Significant Unobservable Inputs (Level 3)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets 0 2,316
Total financial liabilities 7 0
Significant Unobservable Inputs (Level 3) | Derivatives - Gas And Power [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total financial assets [4] 0 2,316
Total financial liabilities [4] $ 7 $ 0
[1] For additional information about our nuclear decommissioning trust, see Note 4—Investments below.
[2] Nuclear decommissioning trust includes investments measured at net asset value per share (or its equivalent) as a practical expedient and these investments have not been categorized in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in our Condensed Consolidated Balance Sheet.
[3] Unrestricted investments and other includes investments that are related to equity securities.
[4] Derivatives - gas and power represent natural gas futures contracts (Level 1 and Level 2) and financial transmission rights (Level 3). Level 1 are indexed against NYMEX. Level 2 are valued by ACES using observable market inputs for similar transactions. Level 3 are valued by ACES using unobservable market inputs, including situations where there is little market activity. Sensitivity in the market price of financial transmission rights could impact the fair value. For additional information about our derivative financial instruments, see Note 1 of the Notes to Consolidated Financial Statements in our 2024 Annual Report on Form 10-K.