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INCOME TAXES - Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Changes in unrecognized tax benefits [Roll Forward] |  |  |
Beginning balance | $ 116 | $ 80 | $ 47
Increase from prior periods | 10 | 88 | 33
Decrease from prior periods | (44) |  |
Ending balance | 82 | 116 | 80
Estimated loss on plants under construction |  |  |
Changes in unrecognized tax benefits [Roll Forward] |  |  |
Statute of limitations expiration |  | (52) |
Georgia Power |  |  |
Changes in unrecognized tax benefits [Roll Forward] |  |  |
Beginning balance | 77 | 0 | 0
Increase from prior periods | 0 | 86 | 0
Decrease from prior periods | (43) |  |
Ending balance | 34 | 77 | 0
Georgia Power | Estimated loss on plants under construction |  |  |
Changes in unrecognized tax benefits [Roll Forward] |  |  |
Statute of limitations expiration |  | (9) |
Southern Company Gas |  |  |
Changes in unrecognized tax benefits [Roll Forward] |  |  |
Beginning balance | 34 | 32 | 0
Increase from prior periods | 10 | 2 | 32
Decrease from prior periods | 0 |  |
Ending balance | $ 44 | 34 | $ 32
Southern Company Gas | Estimated loss on plants under construction |  |  |
Changes in unrecognized tax benefits [Roll Forward] |  |  |
Statute of limitations expiration |  | $ 0 |

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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 217 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482663/740-10-55-217 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-15A Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 10B -Publisher FASB -URI https://asc.fasb.org/1943274/2147482525/740-10-45-10B + Details
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