CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Southern Company (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 1,368	$ 1,443
Southern Holdings Company
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 126	$ 112