Consolidated Entities and Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Investment Balance	$ 1,382	$ 1,443
SOUTHERN Co GAS
Schedule of Equity Method Investments [Line Items]
Investment Balance	1,252	1,276
SOUTHERN Co GAS | SNG
Schedule of Equity Method Investments [Line Items]
Investment Balance	1,220	1,243
SOUTHERN Co GAS | Other
Schedule of Equity Method Investments [Line Items]
Investment Balance	$ 32	$ 33