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CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Commitments (Details) - Georgia Power - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
MEAG Power |  |  |
Loss Contingencies [Line Items] |  |  |
Percent ownership | 5.00% |  |
Plant Vogtle Units 1 and 2 |  |  |
Loss Contingencies [Line Items] |  |  |
Capacity payments | $ 6 | $ 5 | $ 6
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract] |  |  |
Recorded unconditional purchase obligation | 42 |  |
Recorded unconditional purchase obligation, year one | 4 |  |
Recorded unconditional purchase obligation, year two | 3 |  |
Recorded unconditional purchase obligation, year three | 3 |  |
Recorded unconditional purchase obligation, year four | 3 |  |
Recorded unconditional purchase obligation, year five | 1 |  |
Recorded unconditional purchase obligation, after year five | $ 28 |  |

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