Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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STOCK COMPENSATION - Aggregate Intrinsic Value for Options Exercised (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	$ 29
Aggregate intrinsic value for options exercisable	29
Intrinsic value of options exercised	49	$ 34	$ 38
Tax benefit of options exercised	12	7	9
Georgia Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Intrinsic value of options exercised	15	14	9
Tax benefit of options exercised	4	$ 3	$ 2
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Mississippi Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Alabama Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Southern Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	$ 0