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DERIVATIVES - Energy-Related Derivative Contracts (Details) - Energy-related, Natural Gas MMBTU in Millions | Dec. 31, 2021 MMBTU
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Derivative [Line Items] |
Net Purchased mmBtu | 311
Alabama Power |
Derivative [Line Items] |
Net Purchased mmBtu | 74
Georgia Power |
Derivative [Line Items] |
Net Purchased mmBtu | 89
Mississippi Power |
Derivative [Line Items] |
Net Purchased mmBtu | 75
Southern Power |
Derivative [Line Items] |
Net Purchased mmBtu | 5
Southern Company Gas |
Derivative [Line Items] |
Net Purchased mmBtu | 68
Long | Not Designated as Hedging Instrument | Southern Company Gas |
Derivative [Line Items] |
Derivative nonmonetary notional amount net long short position volume | 74
Short | Not Designated as Hedging Instrument | Southern Company Gas |
Derivative [Line Items] |
Derivative nonmonetary notional amount net long short position volume | 6

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