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DERIVATIVES - Derivative Financial Statement Presentation and Amounts With Balance Sheet Offsetting (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | $ 55 | $ 211
Derivative asset, gross amount offset | (23) | (70)
Derivative asset, net amounts recognized in the balance sheets | 32 | 141
Derivative liability, gross amounts recognized | 744 | 728
Derivative liability, gross amounts offset | (85) | (111)
Derivative liability, gross amounts recognized in balance sheets | $ 659 | $ 617
Derivative asset, statement of financial position, extensible enumeration, not disclosed, flag | Net amounts recognized in the Balance Sheets(b) | Net amounts recognized in the Balance Sheets(b)
Collateral already posted, aggregate fair value | $ 62 |
Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 9 | $ 15
Derivative liability, gross amounts recognized | 10 | 14
Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 1 | 2
Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 2 | 1
Energy-related derivatives | Assets from risk management activities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 8 | 13
Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 8 | 13
Interest rate derivatives |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized in balance sheets | 52 |
Alabama Power |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amount offset | (10) | (24)
Derivative asset, net amounts recognized in the balance sheets | 5 | 38
Derivative liability, gross amounts offset | (10) | (24)
Derivative liability, gross amounts recognized in balance sheets | 100 | 15
Collateral already posted, aggregate fair value | 0 |
Georgia Power |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 13 | 42
Derivative asset, gross amount offset | (11) | (21)
Derivative asset, net amounts recognized in the balance sheets | 2 | 21
Derivative liability, gross amounts recognized | 124 | 62
Derivative liability, gross amounts offset | (11) | (21)
Derivative liability, gross amounts recognized in balance sheets | 113 | 41
Georgia Power | Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 1 | 0
Georgia Power | Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 0 | 1
Mississippi Power |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amount offset | (14) | (17)
Derivative asset, net amounts recognized in the balance sheets | 1 | 42
Derivative liability, gross amounts offset | (14) | (17)
Derivative liability, gross amounts recognized in balance sheets | 47 | 15
Southern Power |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, net amounts recognized in the balance sheets | 3 | 8
Derivative liability, gross amounts recognized in balance sheets | 27 | 59
Collateral already posted, aggregate fair value | 0 |
Southern Power | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 3
Derivative liability, gross amounts recognized | 0 | 0
Southern Power | Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 0 | 0
Southern Power | Energy-related derivatives | Other current assets | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 2
Southern Power | Interest rate derivatives |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized in balance sheets | 0 |
Southern Company Gas |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 9 | 28
Derivative asset, gross amount offset | 12 | 0
Derivative asset, net amounts recognized in the balance sheets | 21 | 28
Derivative liability, gross amounts recognized | 137 | 151
Derivative liability, gross amounts offset | (50) | (41)
Derivative liability, gross amounts recognized in balance sheets | 87 | 110
Collateral already posted, aggregate fair value | 62 | 41
Southern Company Gas | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 8 | 12
Derivative liability, gross amounts recognized | 10 | 13
Southern Company Gas | Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 1 | 1
Southern Company Gas | Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 2 | 1
Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 7 | 11
Southern Company Gas | Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 8 | 12
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 43 | 175
Derivative liability, gross amounts recognized | 315 | 165
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 31 | 52
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 117 | 44
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 12 | 123
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 198 | 121
Hedging Instruments for Regulatory Purposes | Alabama Power | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 15 | 62
Derivative liability, gross amounts recognized | 110 | 39
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 9 | 20
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 41 | 18
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 69 | 21
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 6 | 42
Hedging Instruments for Regulatory Purposes | Georgia Power | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 12 | 42
Derivative liability, gross amounts recognized | 124 | 61
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 10 | 6
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 42 | 18
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 82 | 43
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 2 | 36
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 15 | 59
Derivative liability, gross amounts recognized | 61 | 32
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 12 | 26
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 34 | 8
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 27 | 24
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 3 | 33
Hedging Instruments for Regulatory Purposes | Southern Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 1
Hedging Instruments for Regulatory Purposes | Southern Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 0 | 0
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 1
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 4 | 4
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 1 | 12
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 20 | 33
Cash Flow and Fair Value Hedging | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 3 | 21
Derivative liability, gross amounts recognized | 419 | 549
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 3 | 6
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 4 | 4
Cash Flow and Fair Value Hedging | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 3
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 29 | 27
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 190 | 240
Cash Flow and Fair Value Hedging | Interest rate derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 12
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 74 | 62
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 88 | 182
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 34 | 34
Cash Flow and Fair Value Hedging | Southern Power | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 3 | 5
Derivative liability, gross amounts recognized | 27 | 59
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 3 | 5
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 5 | 12
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 11 | 36
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 11 | 11
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other current assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 4
Derivative liability, gross amounts recognized | 107 | 105
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 3
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 24 | 15
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other deferred charges and assets | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | 59 | 72
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Assets from risk management activities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative asset, gross amounts recognized | 0 | 0
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other current liabilities | Designated as Hedging Instrument |  |
Fair value of energy-related derivatives and interest rate derivatives |  |
Derivative liability, gross amounts recognized | $ 20 | $ 14

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