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RATE MATTERS - February 2021 Severe Winter Weather Impacts in SPP (Details) - USD ($) $ in Millions | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2025 | Dec. 31, 2024 | Mar. 31, 2021
Public Utilities, General Disclosures [Line Items] |  |  |
Noncurrent Regulatory Assets | $ 4,950.2 | $ 5,129.2 |
SWEPCo |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Noncurrent Regulatory Assets | 922.2 | 921.3 |
February 2021 Severe Storm Fuel Costs | SWEPCo |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Noncurrent Regulatory Assets | 121.9 | 180.5 |
February 2021 Severe Storm Fuel Costs | Arkansas | SWEPCo |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Noncurrent Regulatory Assets | $ 25.1 | 37.2 |
Approved Recovery Period | 6 years |  |
February 2021 Severe Storm Fuel Costs | Louisiana | SWEPCo |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Noncurrent Regulatory Assets | $ 47.2 | 70.6 |
Approved Recovery Period |  |  | 5 years
February 2021 Severe Storm Fuel Costs | Texas | SWEPCo |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Noncurrent Regulatory Assets | $ 49.6 | $ 72.7 |
Approved Recovery Period | 5 years |  |
Approved Carrying Charge | 1.65% |  |

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