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REGULATORY MATTERS - APC Rate CNP New Plant (Details) - Alabama Power - USD ($) $ in Millions | Mar. 24, 2023 | Dec. 01, 2023 | Oct. 03, 2022
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Public Utilities, General Disclosures [Line Items] |  |  |
Increase to annual revenue requirement |  | $ 91 | $ 34
Increase to annual revenue requirement, percentage |  | 1.40% | 0.60%
Requested rate increase (decrease), amount | $ 78 |  |
Requested rate increase (decrease), percentage | 1.10% |  |

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