v3.25.2
Revenue Local Power Company Contracts (Details)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 30, 2025
USD ($)
Units
Jun. 30, 2025
USD ($)
Units
Long-term Contract for Purchase of Electric Power [Line Items]    
Total long-duration contracts revenue recognition | $ 2,967 8,782
Total percentage of operating revenues 89.80% 90.00%
Number of LPCs signed LTA 148 148
Total Number of LPCs 153 153
5-year Termination Notice [Member]    
Long-term Contract for Purchase of Electric Power [Line Items]    
Revenues | $ $ 426 $ 1,170
Percentage of total operating revenues 12.90% 12.00%
Number of LPCs signed LTA 5 5
20-year Termination Notice [Member]    
Long-term Contract for Purchase of Electric Power [Line Items]    
Revenues | $ $ 2,541 $ 7,612
Percentage of total operating revenues 76.90% 78.00%
Number of LPCs signed LTA 148 148