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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

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