v3.25.3
Employee Benefit Plans (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Pension plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 5 $ 6 $ 17 $ 18
Interest cost 20 18 59 55
Expected return on plan assets (20) (19) (60) (56)
Amortization of net loss 7 7 21 21
Net periodic cost (benefit) 12 12 37 38
Total contributions expected in current year 116   116  
Total contributions to the plans during the period 21   101  
Pension plans | Houston Electric        
Defined Benefit Plan Disclosure [Line Items]        
Total contributions expected in current year 0   0  
Total contributions to the plans during the period 0   0  
Pension plans | CERC        
Defined Benefit Plan Disclosure [Line Items]        
Total contributions expected in current year 0   0  
Total contributions to the plans during the period 0   0  
Postretirement benefit plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 1 0 1 1
Interest cost 3 3 10 9
Expected return on plan assets (1) (1) (4) (4)
Amortization of prior service cost (credit) (1) (1) (2) (2)
Amortization of net loss (2) (2) (7) (6)
Net periodic cost (benefit) 0 (1) (2) (2)
Total contributions expected in current year 10   10  
Total contributions to the plans during the period 3   10  
Postretirement benefit plans | Houston Electric        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 0 0 0 0
Interest cost 1 1 4 4
Expected return on plan assets (1) (1) (3) (3)
Amortization of prior service cost (credit) (2) (1) (4) (4)
Amortization of net loss (1) (1) (4) (3)
Net periodic cost (benefit) (3) (2) (7) (6)
Total contributions expected in current year 1   1  
Total contributions to the plans during the period 0   1  
Postretirement benefit plans | CERC        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 0 0 0 0
Interest cost 2 1 4 3
Expected return on plan assets 0 (1) (1) (1)
Amortization of prior service cost (credit) 1 1 2 2
Amortization of net loss (1) (1) (3) (2)
Net periodic cost (benefit) 2 $ 0 2 $ 2
Total contributions expected in current year 6   6  
Total contributions to the plans during the period $ 2   $ 6