v3.26.1
Selected Balance Sheet Data - Inventories (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Inventory [Line Items]    
Total Inventories $ 31 $ 33
Materials and supplies    
Inventory [Line Items]    
Inventories 20 16
Fuel    
Inventory [Line Items]    
Inventories 8 10
Natural gas    
Inventory [Line Items]    
Inventories $ 3 $ 7