v3.25.2
Commodity Derivatives (Details)
MWh in Millions, MMBTU in Millions, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
USD ($)
MMBTU
MWh
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
MMBTU
MWh
Jun. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
MWh
MMBTU
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Miscellaneous investments $ 55   $ 55   $ 54
Other Derivative Instruments          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Pre-tax fair value gains (losses) recognized during the period in accumulated other comprehensive loss 0 $ 0 0 $ 0  
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities (2) 0 (4) 4  
Designated as Hedging Instrument [Member] | Cash Flow Hedges          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Pre-tax fair value gains (losses) recognized during the period in accumulated other comprehensive loss 7   5 16  
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities     0 0  
Cash flow hedge commodity          
Derivative [Line Items]          
Commodity contracts designated as cash flow hedges $ 0   $ 0    
Electric commodity          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Derivative, Nonmonetary Notional amount | MWh [1],[2] 47   47   31
Electric commodity | Other Derivative Instruments          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities $ (2) 0 $ (5) 1  
Natural Gas Commodity          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Derivative, Nonmonetary Notional amount | MMBTU [1],[2] 47   47   57
Electric Commodity | Other Derivative Instruments          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred $ 0 0 $ 0 0  
Natural gas commodity | Other Derivative Instruments          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Pre-tax fair value gains (losses) recognized during the period in accumulated other comprehensive loss   0 0 0  
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities   $ 0 1 3  
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedges          
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract]          
Pre-tax fair value gains (losses) recognized during the period in accumulated other comprehensive loss $ 7   5 16  
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities     $ 0 $ 0  
[1] Not reflective of net positions in the underlying commodities.
[2] Notional amounts for options included on a gross basis but weighted for the probability of exercise.