ASSET RETIREMENT OBLIGATIONS - Accumulated Provisions for the External Decommissioning Trust Funds (Details) - External decommissioning trust funds - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	$ 1,018	$ 1,217
Plant Farley | Alabama Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	1,125	1,324
Plant Hatch | Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	628	757
Plant Vogtle Units 1 and 2 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	382	460
Plant Vogtle Unit 3 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	$ 8	$ 0