v3.26.1
Fair Value of Financial Assets and Liabilities - Impact of Derivative Activities on Income and Accumulated Other Comprehensive Loss (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income [Abstract]        
Derivative instruments designated as fair value hedges $ 0 $ 0 $ 0 $ 0
Interest Rate Swap [Member]        
Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income [Abstract]        
Derivative Liability, Notional Amount 0   0  
Other Derivative Instruments        
Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income [Abstract]        
Pre-Tax fair value gains (losses) recognized during the period in (59) 12 (71) 20
Other Derivative Instruments | Electric Commodity        
Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income [Abstract]        
Pre-Tax fair value gains (losses) recognized during the period in $ (59) $ 12 $ (71) $ 20