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REGULATORY MATTERS - APC Rate RSE (Details) - Alabama Power - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Jan. 31, 2019 | Dec. 31, 2025 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Jan. 01, 2021
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Rate adjustment period |  |  | 2 years |  |  |
Maximum percentage of rate RSE |  |  | 4.00% |  |  |
Maximum annual percentage of ratio rate |  |  | 5.00% |  |  |
Adjusting point of weighted cost of equity |  |  | 5.98% |  |  |
Percent of basis points |  |  | 0.07% |  |  |
Percent of designated customer value benchmark survey |  |  | 33.33% |  |  |
Authorized ROE |  |  | 51.60% | 51.60% |  |
Weighted common equity return | 6.15% |  |  | 6.21% |  |
Customer refundable fees, refund payments, tranche one, percentage |  |  | 25.00% |  |  |
Customer refundable fees, refund payments, tranche two, percentage |  |  | 40.00% |  |  |
Customer refundable fees, refund payments, tranche two, percentage |  |  | 75.00% |  |  |
Customer refundable fees, refund payments, tranche one, review year with rate RSE upward adjustment, percentage |  |  | 50.00% |  |  |
Contract with customer, liability, bill credits |  |  |  | $ 55 | $ 50 |
Rate RSE increase |  |  |  |  |  | 4.09%
Rate RSE increase amount |  |  |  |  |  | $ 228
Rate RSE refund liability |  |  | $ 181 | $ 50 | $ 53 |
Rate RSE refund liability, portion attributable to reduce under recovered balance |  |  | $ 126 |  |  |
Minimum |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public utilities, actual weighted common equity return, threshold, percentage |  |  | 6.15% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one |  |  | 6.15% | 6.15% | 6.15% |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two |  |  | 6.65% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three |  |  | 7.15% |  |  |
Public utilities, actual weighted common equity return, threshold, review year with rate RSE upward adjustment, percentage |  |  | 6.15% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one |  |  | 6.15% |  |  |
Maximum |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public utilities, actual weighted common equity return, threshold, percentage |  |  | 7.65% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one |  |  | 6.65% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two |  |  | 7.15% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three |  |  | 7.65% |  |  |
Customer refundable fees, refund payments, percentage |  |  | 7.65% |  |  |
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one |  |  | 6.90% |  |  |
Customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage |  |  | 6.90% |  |  |
Scenario, Forecast |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Authorized ROE |  | 55.00% |  |  |  |

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