DERIVATIVES - Interest Rate Derivatives (Details) - Interest rate derivatives $ in Millions	12 Months Ended
Dec. 31, 2024 USD ($)
Derivative [Line Items]
Notional Amount	$ 1,900
Fair Value Gain (Loss) December 31, 2024	(269)
Southern Company \| Fair Value Hedges of Existing Debt \| Date one
Derivative [Line Items]
Notional Amount	$ 400
Weighted Average Interest Rate Paid	0.80%
Interest Rate Received	1.75%
Fair Value Gain (Loss) December 31, 2024	$ (42)
Southern Company \| Fair Value Hedges of Existing Debt \| Date 2
Derivative [Line Items]
Notional Amount	$ 1,000
Weighted Average Interest Rate Paid	2.48%
Interest Rate Received	3.70%
Fair Value Gain (Loss) December 31, 2024	$ (143)
Southern Company Gas \| Fair Value Hedges of Existing Debt
Derivative [Line Items]
Notional Amount	$ 500
Weighted Average Interest Rate Paid	0.49%
Interest Rate Received	1.75%
Fair Value Gain (Loss) December 31, 2024	$ (84)

Fair value gain (Loss).

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- Definition

Notional amount of interest rate derivatives, interest rate paid.

+ References

No definition available.

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- Definition

Notional amount of interest rate derivatives, interest rate received.

+ References

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- Definition

Nominal or face amount used to calculate payments on the derivative liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
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