v3.25.2
Regulatory Matters - Narrative (Details)
$ in Millions
12 Months Ended
Jul. 03, 2025
USD ($)
Jun. 30, 2025
USD ($)
MW
Jun. 04, 2025
coal_fueled_electric_generating_unit
transaction
MW
May 27, 2025
leaseUnit
lease
MW
kW
Apr. 28, 2025
Mar. 19, 2025
USD ($)
Dec. 19, 2024
coal_fueled_electric_generating_unit
MW
Sep. 11, 2024
MW
Mar. 23, 2023
USD ($)
Dec. 31, 2021
lease
Jun. 20, 2025
USD ($)
May 02, 2025
USD ($)
Dec. 31, 2024
USD ($)
Nov. 08, 2024
USD ($)
Jun. 29, 2023
USD ($)
Jan. 04, 2023
USD ($)
Regulatory Assets [Line Items]                                
Regulatory assets   $ 167.0                     $ 239.0      
Regulatory assets   3,088.0                     3,108.0      
Cost of recovery for non customer specific, maximum | MW               32                
Return on investment for power consumption | MW               5                
Anticipated future transaction one (or more) | transaction     1                          
Long term lease, number of small power generating units | leaseUnit       36                        
Operating lease, term of contract (in months)       36 months                        
Regulatory asset, authorized issuance costs                     $ 396.0          
Public Utility Commission Of Texas                                
Regulatory Assets [Line Items]                                
Regulatory assets   8.0                     8.0      
IURC                                
Regulatory Assets [Line Items]                                
Regulatory asset, authorized issuance costs                               $ 350.0
February 2021 Winter Storm                                
Regulatory Assets [Line Items]                                
Regulatory assets   67.0                            
Regulatory assets   19.0                     19.0      
CERC                                
Regulatory Assets [Line Items]                                
Regulatory assets   148.0                     238.0      
Regulatory assets   781.0                     903.0      
CERC | February 2021 Winter Storm                                
Regulatory Assets [Line Items]                                
Regulatory assets   67.0                            
Houston Electric                                
Regulatory Assets [Line Items]                                
Regulatory assets   1,396.0                     1,284.0      
Number of leases entered into | lease       2           2            
Expenses associated with short-term lease   84.0                     89.0      
Expenses associated with long term lease   $ 156.0                     158.0      
Number of megawatts of mobile generation | MW   505   20                        
Cost of recovery for non customer specific, maximum     32 1,250     32                  
Number of fleet capacity | coal_fueled_electric_generating_unit     15       15                  
Cost of recovery for non customer specific, minimum     27 200     27                  
Houston Electric | Energy Rental Solutions                                
Regulatory Assets [Line Items]                                
Number of megawatts of mobile generation | MW       200                        
Long term lease, number of small power generating units | leaseUnit       1                        
Houston Electric | Assets With Lease Payments                                
Regulatory Assets [Line Items]                                
Escrow deposit   $ 71.0                            
Houston Electric | Public Utility Commission Of Texas                                
Regulatory Assets [Line Items]                                
Regulatory assets   8.0                     8.0      
Amortization term (in years)         5 years                      
Houston Electric | February 2021 Winter Storm                                
Regulatory Assets [Line Items]                                
Regulatory assets   19.0                     19.0      
SIGECO | Subsidiaries                                
Regulatory Assets [Line Items]                                
Regulatory asset, issued                             $ 341.0  
February 2021 Winter Storm Event                                
Regulatory Assets [Line Items]                                
Regulatory assets   30.0                            
February 2021 Winter Storm Event | Customer Rate Relief Bond Financing                                
Regulatory Assets [Line Items]                                
Cash proceeds received from government grants                 $ 1,100.0              
February 2021 Winter Storm Event | CERC                                
Regulatory Assets [Line Items]                                
Regulatory asset, approximate total gas cost   2,000.0                            
Regulatory assets                         67.0      
Regulatory assets   30.0                     $ 67.0      
February 2021 Winter Storm Event | CERC | Customer Rate Relief Bond Financing                                
Regulatory Assets [Line Items]                                
Cash proceeds received from government grants                 $ 1,100.0              
May 2024 Storm Events                                
Regulatory Assets [Line Items]                                
Estimated case processing expenses and carrying costs                           $ 502.0    
Entitled to recover a total           $ 396.0                    
Transmission-related costs           29.0                    
Distribution-related costs           17.5                    
Reduction in cost           $ 10.0                    
Hurricane Beryl                                
Regulatory Assets [Line Items]                                
Estimated case processing expenses and carrying costs                       $ 1,300.0        
Intervenor disallowance positions cost   $ 298.8                            
Hurricane Beryl | Subsequent Event                                
Regulatory Assets [Line Items]                                
Staff disallowance positions cost $ 4.7