v3.25.0.1
REGULATORY MATTERS - APC Rate NDR and Reliability Reserve Accounting Order (Details) - USD ($)
3 Months Ended 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Jul. 12, 2022
Public Utilities, General Disclosures [Line Items]            
Reclassified amount $ (97,017,000,000) $ (90,703,000,000) $ (97,017,000,000) $ (90,703,000,000)    
Other regulatory assets 804,000,000 1,120,000,000 804,000,000 1,120,000,000    
Reliability reserve, amount deferred 84,000,000 63,000,000 84,000,000 63,000,000 $ 191,000,000  
Revision of Prior Period, Reclassification, Adjustment            
Public Utilities, General Disclosures [Line Items]            
Reclassified amount         600,000,000  
Other utility plant, net         600,000,000  
Alabama Power            
Public Utilities, General Disclosures [Line Items]            
Minimum natural disaster reserve balance, triggering establishment charge 50,000,000   50,000,000      
Natural disaster reserve authorized limit 75,000,000   75,000,000   35,000,000  
Maximum rate NDR charge per month, monthly residential customer account 2.50   2.50     $ 5.00
Maximum rate NDR charge per month, monthly nonresidential customer account 5.00   5.00     $ 10.00
Annual recovery amount     12,000,000 12,000,000 14,000,000  
NDR, expected recovery amount     12,000,000      
Regulatory asset, amortization period 70,000,000 76,000,000 70,000,000 76,000,000    
Reclassified amount (24,760,000,000) (24,298,000,000) (24,760,000,000) (24,298,000,000)    
Other regulatory assets 332,000,000 385,000,000 332,000,000 385,000,000    
Reliability reserve, amount deferred 63,000,000 52,000,000 $ 63,000,000 $ 52,000,000 $ 166,000,000  
Alabama Power | Reliability reserves            
Public Utilities, General Disclosures [Line Items]            
Accrual $ 12,000,000 $ 23,000,000        
Alabama Power | Maximum            
Public Utilities, General Disclosures [Line Items]            
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits     48 months      
Alabama Power | Minimum            
Public Utilities, General Disclosures [Line Items]            
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits     24 months