v3.25.0.1
ASSET RETIREMENT OBLIGATIONS - Details of AROs Included in the Balance Sheets (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year $ 10,317 $ 10,840
Liabilities incurred 130 90
Liabilities settled (566) (617)
Accretion expense 400 403
Cash flow revisions (347) (399)
Balance at end of year 9,934 10,317
Alabama Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 4,158 4,287
Liabilities incurred 8 0
Liabilities settled (254) (270)
Accretion expense 153 156
Cash flow revisions (7) (15)
Balance at end of year 4,058 4,158
Georgia Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 5,665 6,034
Liabilities incurred 120 90
Liabilities settled (270) (304)
Accretion expense 232 230
Cash flow revisions (332) (385)
Balance at end of year 5,415 5,665
Mississippi Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 168 179
Liabilities incurred 0 0
Liabilities settled (17) (18)
Accretion expense 5 5
Cash flow revisions (8) 2
Balance at end of year 148 168
Southern Power    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year 150 144
Liabilities incurred 2 0
Liabilities settled 0 0
Accretion expense 7 6
Cash flow revisions 0 0
Balance at end of year $ 159 $ 150