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DERIVATIVES - Foreign Currency Derivatives (Details) € in Millions, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2023 USD ($) | Dec. 31, 2023 EUR (€) | Dec. 31, 2022 USD ($)
Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt |  |  |
Derivative [Line Items] |  |  |
Pay Notional | $ 2,040 |  |
Receive Notional | € |  | € 1,750 |
Fair Value Gain (Loss) December 31, 2023 | (122) |  |
Southern Power |  |  |
Derivative [Line Items] |  |  |
Fair Value Gain (Loss) December 31, 2023 | (12) |  | $ (31)
Southern Power | Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt |  |  |
Derivative [Line Items] |  |  |
Pay Notional | $ 564 |  |
Pay Rate | 3.78% |  |
Receive Notional | € |  | 500 |
Receive Rate | 1.85% |  |
Southern Power | Foreign currency derivatives | Date | Cash Flow Hedges of Forecasted Debt |  |  |
Derivative [Line Items] |  |  |
Fair Value Gain (Loss) December 31, 2023 | $ (22) |  |
Southern Company | Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt |  |  |
Derivative [Line Items] |  |  |
Fair Value Gain (Loss) December 31, 2023 | (100) |  |
Southern Company | Foreign currency derivatives | Date | Fair Value Hedges of Existing Debt |  |  |
Derivative [Line Items] |  |  |
Pay Notional | $ 1,476 |  |
Pay Rate | 3.39% |  |
Receive Notional | € |  | € 1,250 |
Receive Rate | 1.88% |  |

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