v3.10.0.1
Financing - Preferred Stock Redemption (Details) - Alabama Power
1 Months Ended 12 Months Ended
Sep. 30, 2017
$ / shares
shares
Dec. 31, 2018
$ / shares
shares
Oct. 02, 2022
$ / shares
4.92% Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage   0.0492  
Par Value/Stated Capital Per Share (in dollars per share)   $ 100  
Shares outstanding (in shares) | shares   80,000  
Redemption Price Per Share (in dollars per share)   $ 103.23  
4.72% Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage   0.0472  
Par Value/Stated Capital Per Share (in dollars per share)   $ 100  
Shares outstanding (in shares) | shares   50,000  
Redemption Price Per Share (in dollars per share)   $ 102.18  
4.64% Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage   0.0464  
Par Value/Stated Capital Per Share (in dollars per share)   $ 100  
Shares outstanding (in shares) | shares   60,000  
Redemption Price Per Share (in dollars per share)   $ 103.14  
4.60% Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage   0.046  
Par Value/Stated Capital Per Share (in dollars per share)   $ 100  
Shares outstanding (in shares) | shares   100,000  
Redemption Price Per Share (in dollars per share)   $ 104.20  
4.52% Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage   0.0452  
Par Value/Stated Capital Per Share (in dollars per share)   $ 100  
Shares outstanding (in shares) | shares   50,000  
Redemption Price Per Share (in dollars per share)   $ 102.93  
4.20% Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage   0.042  
Par Value/Stated Capital Per Share (in dollars per share)   $ 100  
Shares outstanding (in shares) | shares   135,115  
Redemption Price Per Share (in dollars per share)   $ 105.00  
5.00% Class A Preferred Stock      
Debt Instrument, Redemption [Line Items]      
Temporary equity, dividend rate percentage 0.05 0.05  
Par Value/Stated Capital Per Share (in dollars per share) $ 25 $ 25  
Shares outstanding (in shares) | shares 10,000,000 10,000,000  
5.00% Class A Preferred Stock | Scenario, Forecast      
Debt Instrument, Redemption [Line Items]      
Redemption Price Per Share (in dollars per share)     $ 25.50