v3.25.0.1
DERIVATIVES - Schedule of Unrealized Gain (Loss) Recognized in the Balance Sheet (Details) - Energy-related derivatives - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) $ (50) $ (257)
Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (61) (180)
Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (5) (87)
Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 8 9
Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 8 1
Alabama Power    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (16) (95)
Alabama Power | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (23) (67)
Alabama Power | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 (32)
Alabama Power | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 4 4
Alabama Power | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 3 0
Georgia Power    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (22) (112)
Georgia Power | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (26) (80)
Georgia Power | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 (33)
Georgia Power | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 0
Georgia Power | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 4 1
Mississippi Power    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (15) (46)
Mississippi Power | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (11) (25)
Mississippi Power | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (5) (22)
Mississippi Power | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 1
Mississippi Power | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 1 0
Southern Company Gas    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 3 (4)
Southern Company Gas | Other regulatory assets, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) (1) (8)
Southern Company Gas | Other regulatory assets, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 0 0
Southern Company Gas | Other regulatory liabilities, current    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) 4 4
Southern Company Gas | Other regulatory liabilities, deferred    
Derivatives, Fair Value [Line Items]    
Total energy-related derivative gains (losses) $ 0 $ 0