v3.25.0.1
FINANCING - Long-Term Debt (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Debt Instrument [Line Items]    
Finance lease obligations $ 287 $ 298
Unamortized fair value adjustment 275 302
Unamortized debt premium (discount), net (58) (198)
Unamortized debt issuance expense (419) (290)
Total long-term debt 63,486 59,686
Less: Amount due within one year 4,718 2,476
Long-Term Debt $ 58,768 57,210
Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.33%  
Long-term debt, gross $ 44,862 40,235
Junior subordinated notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.32%  
Long-term debt, gross $ 7,389 8,333
FFB loans    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 2.88%  
Long-term debt, gross $ 4,703 4,788
Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.15%  
Long-term debt, gross $ 3,379 3,400
First mortgage bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.79%  
Long-term debt, gross $ 2,775 2,500
Medium-term notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 7.03%  
Long-term debt, gross $ 84 84
Other long-term debt    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.96%  
Long-term debt, gross $ 209 234
Alabama Power    
Debt Instrument [Line Items]    
Finance lease obligations 4 5
Unamortized debt premium (discount), net (19) (20)
Unamortized debt issuance expense (67) (73)
Total long-term debt 11,154 11,183
Less: Amount due within one year 655 223
Long-Term Debt $ 10,499 10,960
Alabama Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.94%  
Long-term debt, gross $ 9,875 9,875
Alabama Power | Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.11%  
Long-term debt, gross $ 1,300 1,321
Alabama Power | Other long-term debt    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 6.11%  
Long-term debt, gross $ 61 75
Georgia Power    
Debt Instrument [Line Items]    
Finance lease obligations 261 240
Unamortized debt premium (discount), net (21) (19)
Unamortized debt issuance expense (123) (122)
Total long-term debt 18,350 16,700
Less: Amount due within one year 966 502
Long-Term Debt $ 17,384 16,198
Georgia Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.49%  
Long-term debt, gross $ 11,292 9,575
Georgia Power | Junior subordinated notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 5.00%  
Long-term debt, gross $ 270 270
Georgia Power | FFB loans    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 2.88%  
Long-term debt, gross $ 4,703 4,788
Georgia Power | Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.18%  
Long-term debt, gross $ 1,968 1,968
Mississippi Power    
Debt Instrument [Line Items]    
Finance lease obligations 14 16
Unamortized debt premium (discount), net 2 1
Unamortized debt issuance expense (9) (9)
Total long-term debt 1,693 1,644
Less: Amount due within one year 12 201
Long-Term Debt $ 1,681 1,443
Mississippi Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.33%  
Long-term debt, gross $ 1,575 1,525
Mississippi Power | Pollution control revenue bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.16%  
Long-term debt, gross $ 111 111
Southern Power    
Debt Instrument [Line Items]    
Finance lease obligations 0 0
Unamortized debt premium (discount), net (4) (4)
Unamortized debt issuance expense (11) (13)
Total long-term debt 2,680 2,711
Less: Amount due within one year 500 0
Long-Term Debt 2,180 2,711
Fair value gain (loss) $ (45) (12)
Southern Power | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.05%  
Long-term debt, gross $ 2,695 2,728
Southern Company Gas    
Debt Instrument [Line Items]    
Finance lease obligations 0 0
Unamortized fair value adjustment 275 302
Unamortized debt premium (discount), net (9) (8)
Unamortized debt issuance expense (37) (34)
Total long-term debt 8,531 7,833
Less: Amount due within one year 302 0
Long-Term Debt $ 8,229 7,833
Southern Company Gas | Senior notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 4.41%  
Long-term debt, gross $ 5,375 4,930
Southern Company Gas | First mortgage bonds    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.79%  
Long-term debt, gross $ 2,775 2,500
Southern Company Gas | Medium-term notes    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 7.03%  
Long-term debt, gross $ 84 84
Southern Company Gas | Other long-term debt    
Debt Instrument [Line Items]    
Weighted Average Interest Rate 3.81%  
Long-term debt, gross $ 68 $ 59