REGULATORY MATTERS - Nuclear Construction Regulatory Matters (Details) - Georgia Power - USD ($) $ in Millions								12 Months Ended
	Jan. 01, 2021	Feb. 19, 2020	Feb. 18, 2020	Jan. 01, 2020	Dec. 18, 2018	Jan. 01, 2018	Jan. 01, 2016	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2009	Dec. 31, 2016	Jan. 01, 2013
Loss Contingencies [Line Items]
Retail rate of return on common equity											10.50%						10.95%
Potential decrease each month, percentage											0.01%
Customer refund											$ 55.0
Plant Vogtle Units 3 And 4
Loss Contingencies [Line Items]
Estimated in-service capital cost															$ 4,418.0
Proceeds from recovery of financing costs											2,200.0
Project capital cost forecast											7,300.0
Increase (decrease) in tariff					$ 62.0
Additional construction capital costs														$ 3,300.0
Amendment to estimated in-service capital cost											5,680.0
Retail rate of return on common equity																10.95%
Public utilities, approved return on equity						10.00%	10.00%
Return on equity reduction, negative impact on earnings											$ 75.0	$ 100.0	$ 25.0
Plant Vogtle Units 3 And 4 | Scenario, Forecast
Loss Contingencies [Line Items]
Public utilities, approved return on equity	5.30%			8.30%
Return on equity reduction, negative impact on earnings								$ 190.0	$ 240.0	$ 140.0
Subsequent Event | Plant Vogtle Units 3 And 4
Loss Contingencies [Line Items]
Approval of construction capital costs		$ 674.0
Minimum
Loss Contingencies [Line Items]
Retail rate of return on common equity											9.50%						10.00%
Twentieth Vogtle Construction Monitoring Report | Subsequent Event | Plant Vogtle Units 3 And 4
Loss Contingencies [Line Items]
Approval of construction capital costs			$ 1,200.0
Expenditures related to Georgia Power's portion of an administrative claim filed in the Westinghouse bankruptcy proceedings			21.5
Twenty First Vogtle Construction Monitoring Report | Subsequent Event | Plant Vogtle Units 3 And 4
Loss Contingencies [Line Items]
Maximum guarantee			1,700.0
Approval of construction capital costs			6,700.0
Customer refund			$ 188.0