v3.25.2
Utility Regulatory Assets and Liabilities and Regulatory Matters - Narrative (Details) - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Jul. 31, 2025
Jul. 09, 2025
Jan. 27, 2025
Jul. 31, 2024
Apr. 11, 2024
Dec. 21, 2023
Oct. 06, 2023
Jul. 31, 2023
Mar. 06, 2023
Jun. 30, 2025
Jun. 30, 2024
Sep. 30, 2024
Regulatory Assets                        
Net unrealized gains (losses)                   $ (30) $ (12)  
Gas Utility                        
Regulatory Assets                        
Net unrealized gains (losses)                   $ 1 $ (1) $ 2
Utilities | PAPUC | 2025 Pennsylvania Public Utility Commission For Base Operating Revenues                        
Regulatory Assets                        
Requested rate increase (decrease)     $ 110                  
Utilities | PAPUC | Joint Petition For Approval Of Settlement | Subsequent event                        
Regulatory Assets                        
Requested rate increase (decrease)   $ 70                    
Mountaineer | WVPSC | 2024 IREP Expected                        
Regulatory Assets                        
Requested rate increase (decrease)       $ 19                
Total capital investments       197                
Mountaineer | WVPSC | 2024 IREP Expected | Subsequent event                        
Regulatory Assets                        
Requested rate increase (decrease) $ 24                      
Total capital investments 274                      
Mountaineer | WVPSC | 2024 Infrastructure Replacement and Expansion Plan, Prior Year Under-recovery                        
Regulatory Assets                        
Requested rate increase (decrease)       3                
Mountaineer | WVPSC | 2024 Infrastructure Replacement and Expansion Plan, Prior Year Under-recovery | Subsequent event                        
Regulatory Assets                        
Requested rate increase (decrease) 5                      
Mountaineer | WVPSC | 2024 IREP For 2024                        
Regulatory Assets                        
Total capital investments       74                
Mountaineer | WVPSC | 2024 IREP For 2024 | Subsequent event                        
Regulatory Assets                        
Total capital investments 77                      
Mountaineer | WVPSC | 2024 IREP Recovery                        
Regulatory Assets                        
Total capital investments       $ 418                
Mountaineer | WVPSC | 2024 IREP Recovery | Subsequent event                        
Regulatory Assets                        
Total capital investments $ 445                      
Mountaineer | WVPSC | 2023 IREP Recovery                        
Regulatory Assets                        
Requested rate increase (decrease)               $ 10        
Total capital investments               383        
Mountaineer | WVPSC | 2023 Infrastructure Replacement and Expansion Plan, Capital Investments After 2022                        
Regulatory Assets                        
Requested rate increase (decrease)               6        
Mountaineer | WVPSC | 2023 IREP                        
Regulatory Assets                        
Costs associated with capital investments               131        
Mountaineer | WVPSC | 2023 IREP For 2024                        
Regulatory Assets                        
Costs associated with capital investments               67        
Mountaineer | WVPSC | 2023 Infrastructure Replacement and Expansion Plan, Expected                        
Regulatory Assets                        
Requested rate increase (decrease)               $ (12)        
Mountaineer | WVPSC | Net Revenue Increase                        
Regulatory Assets                        
Requested rate increase (decrease)             $ 14   $ 20      
Mountaineer | WVPSC | Base Rates                        
Regulatory Assets                        
Requested rate increase (decrease)                 38      
Mountaineer | WVPSC | IREP rate                        
Regulatory Assets                        
Requested rate increase (decrease)                 $ (18)      
Mountaineer | WVPSC | Weather normalization adjustment rider                        
Regulatory Assets                        
Adjustment rider period           5 years            
Weather deviates threshold         2.00%              
Approved rate         2.00%