Regulatory Matters - Requested Recovery of Proposed Increases (Details) - GEORGIA POWER CO $ in Millions	Sep. 30, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
2020	$ 560
2021	144
2022	233
Levelized
Public Utilities, General Disclosures [Line Items]
2020	210
2021	0
2022	0
CCR ARO
Public Utilities, General Disclosures [Line Items]
2020	158
2021	139
2022	227
Environmental Compliance Cost Recovery
Public Utilities, General Disclosures [Line Items]
2020	163
2021	0
2022	0
Demand-Side Management
Public Utilities, General Disclosures [Line Items]
2020	12
2021	1
2022	1
Municipal Franchise Fee
Public Utilities, General Disclosures [Line Items]
2020	17
2021	3
2022	$ 5