v3.25.1
Utility Regulatory Assets and Liabilities and Regulatory Matters - Narrative (Details) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jan. 27, 2025
Jul. 31, 2024
Apr. 11, 2024
Dec. 21, 2023
Oct. 06, 2023
Jul. 31, 2023
Mar. 06, 2023
Mar. 31, 2025
Mar. 31, 2024
Sep. 30, 2024
Regulatory Assets                    
Net unrealized gains (losses)               $ 107 $ (54)  
Gas Utility                    
Regulatory Assets                    
Net unrealized gains (losses)               $ 19 $ (7) $ 2
Utilities | PAPUC | 2025 Pennsylvania Public Utility Commission For Base Operating Revenues                    
Regulatory Assets                    
Requested rate increase (decrease) $ 110                  
Mountaineer | WVPSC | 2024 IREP Expected                    
Regulatory Assets                    
Requested rate increase (decrease)   $ 19                
Total capital investments   197                
Mountaineer | WVPSC | 2024 Infrastructure Replacement and Expansion Plan, Prior Year Under-recovery                    
Regulatory Assets                    
Requested rate increase (decrease)   3                
Mountaineer | WVPSC | 2024 IREP For 2024                    
Regulatory Assets                    
Total capital investments   74                
Mountaineer | WVPSC | 2024 IREP Recovery                    
Regulatory Assets                    
Total capital investments   $ 418                
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%