v3.10.0.1
Regulatory Matters - Nuclear Construction (Details) - Georgia Power
$ in Millions
12 Months Ended
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2009
utility
MW
Loss Contingencies [Line Items]      
Number of construction units approved | utility     2
Electric generating capacity (mw) | MW     1,100
Plant Vogtle Units 3 And 4      
Loss Contingencies [Line Items]      
Percent ownership   45.70%  
Construction financing costs   $ 1,900  
Additional base capital costs per month   50  
AFUDC per month   $ 12  
Plant Vogtle Units 3 And 4 | Scenario, Forecast      
Loss Contingencies [Line Items]      
Construction financing costs $ 3,100    
Vogtle Owners | Plant Vogtle Units 3 And 4      
Loss Contingencies [Line Items]      
Period of notice required in the event letters of credit are not renewed   30 days