v3.25.2
RATE MATTERS - Dolet Hills Power Station and Related Fuel Operations (Details) - Dolet Hills Power Station and Related Fuel Operations - SWEPCo - USD ($)
$ in Millions
1 Months Ended
Apr. 30, 2024
Feb. 29, 2024
Sep. 30, 2023
Aug. 31, 2022
Mar. 31, 2021
Jun. 30, 2025
Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]              
Fuel supply provided, percentage             100.00%
Regulatory asset, net investment           $ 70  
Regulatory asset, net under-recovered fuel costs           26  
Louisiana              
Public Utilities, General Disclosures [Line Items]              
Regulatory asset, recovery of fuel costs         $ 20    
Regulatory asset, recovery of fuel costs, deferred         35    
Regulatory asset, fuel disallowance       $ 55      
Regulatory asset, fuel disallowance, deferral       $ 35      
Regulatory asset, refund to customer period       5 years      
Regulatory asset, refund to customer, proposed amount   $ 55          
Regulatory asset, deferral, denial of recovery   $ 35          
Disallowance of fuel costs $ 11            
Regulatory asset           $ 24  
Approved Recovery Period           3 years  
Arkansas              
Public Utilities, General Disclosures [Line Items]              
Regulatory asset, recovery of fuel costs         $ 20    
Regulatory asset, recovery of fuel costs, period         5 years    
Texas              
Public Utilities, General Disclosures [Line Items]              
Regulatory asset, recovery of fuel costs     $ 48