v3.26.3
Fair Value of Financial Assets and Liabilities - Commodity Derivatives (Details)
MWh in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
MWh
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
MWh
Sep. 30, 2025
USD ($)
Dec. 31, 2025
MWh
Other Derivative Instruments          
Derivative [Line Items]          
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities) $ (11) $ 2 $ 39 $ (27)  
Electric Commodity [Member]          
Derivative [Line Items]          
Mwh of electricity | MWh [1] 10   10   7
cash flow hedge commodity          
Derivative [Line Items]          
Commodity contracts designated as cash flow hedges $ 0   $ 0    
Electric Commodity | Other Derivative Instruments          
Derivative [Line Items]          
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities) $ (11) $ 2 $ 39 [2] $ (27) [2]  
[1] Not reflective of net positions in the underlying commodities.
[2] Recorded to electric fuel and purchased power. These derivative settlement gains and losses are shared with electric customers through fuel and purchased energy cost-recovery mechanisms, and reclassified out of income as regulatory assets or liabilities, as appropriate. FTR settlements are shared with customers and do not have a material impact on net income. Presented amounts reflect changes in fair value between auction and settlement dates, but exclude the original auction fair value.