v3.26.1
Fair Value of Financial Assets and Liabilities - Consideration of Credit Risk and Concentrations (Details)
$ in Millions
Jun. 30, 2026
USD ($)
Counterparty
Dec. 31, 2025
USD ($)
Derivative [Line Items]    
Derivative, Gross Liability with Cross Default Position, Aggregate Fair Value | $ $ 0 $ 7
Credit Concentration Risk    
Derivative [Line Items]    
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure 8  
Credit Concentration Risk | Municipal or Cooperative Entities or Other Utilities [Member]    
Derivative [Line Items]    
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure 7  
Credit Concentration Risk | External Credit Rating, Investment Grade [Member]    
Derivative [Line Items]    
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure 1  
Wholesale, trading and non-trading commodity credit exposure for the most significant counterparties | $ $ 1  
Percentage of wholesale, trading and non-trading commodity credit exposure for the most significant counterparties (in hundredths) 3.00%  
Credit Concentration Risk | Internal Investment Grade    
Derivative [Line Items]    
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure 7  
Wholesale, trading and non-trading commodity credit exposure for the most significant counterparties | $ $ 23  
Percentage of wholesale, trading and non-trading commodity credit exposure for the most significant counterparties (in hundredths) 68.00%