INCOME TAXES - NOL Carryforwards (Details) $ in Millions	Dec. 31, 2024 USD ($)
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	$ 265
Operating loss carryforwards, valuation allowance	(82)
Mississippi Power \| Mississippi
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	178
Operating loss carryforwards, valuation allowance	(32)
Southern Power
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	38
Operating loss carryforwards, valuation allowance	(21)
Southern Power \| Oklahoma
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	26
Operating loss carryforwards, valuation allowance	(11)
Southern Power \| Florida
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	10
Operating loss carryforwards, valuation allowance	(10)
Southern Power \| Other states
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	2
Operating loss carryforwards, valuation allowance	0
Other Subsidiaries \| Other states
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	24
Operating loss carryforwards, valuation allowance	(4)
Other Subsidiaries \| New York
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	11
Operating loss carryforwards, valuation allowance	(11)
Other Subsidiaries \| New York City
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	14
Operating loss carryforwards, valuation allowance	$ (14)

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-6

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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 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-3

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The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-2

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