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CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Nuclear Fuel Disposal Costs and Nuclear Insurance (Details) | 12 Months Ended | 108 Months Ended
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Dec. 31, 2021 USD ($) plant | Dec. 31, 2019 USD ($)
Jointly Owned Utility Plant Interests [Line Items] |  |
Maximum fund for public liability claims arising from a single nuclear incident under price - anderson amendments act | $ 13,500,000,000 |
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant | 450,000,000 |
Maximum amount that a company could be assessed per incident for each licensed reactor | 138,000,000 |
Maximum aggregate amount that a reactor can assess in a calendar period for each incident | $ 20,000,000 |
Block period considered for inflation adjustment against maximum assessment per reactor | 5 years |
Maximum deductible waiting period | 182 days |
Maximum coverage per occurrence per unit limit to obtain replacement power | $ 490,000,000 |
Aggregate payment for claims resulting from terrorist acts in one year period | 3,200,000,000 |
Vogtle Units 3 and 4 |  |
Jointly Owned Utility Plant Interests [Line Items] |  |
Maximum limits for accidental property damage occurring during construction | $ 2,750,000,000 |
Alabama Power and Georgia Power |  |
Jointly Owned Utility Plant Interests [Line Items] |  |
Number of nuclear fuel plants | plant | 3 |
Maximum property damage insurance provided to nuclear generating facilities | $ 1,500,000,000 |
Maximum additional coverage provided for losses under excess insurance | 1,250,000,000 |
Maximum additional coverage provided for losses under excess insurance, non-nuclear losses | $ 750,000,000 |
Elected deductible waiting period | 84 days |
Alabama Power |  |
Jointly Owned Utility Plant Interests [Line Items] |  |
Maximum assessment, excluding any applicable state premium taxes | $ 275,000,000 |
Maximum aggregate amount to be paid in one year | 41,000,000 |
Current maximum annual assessments under NEIL policies | 52,000,000 |
Alabama Power | Positive Outcome of Litigation |  |
Jointly Owned Utility Plant Interests [Line Items] |  |
Outstanding claims |  | $ 110,000,000
Georgia Power |  |
Jointly Owned Utility Plant Interests [Line Items] |  |
Maximum assessment, excluding any applicable state premium taxes | 267,000,000 |
Maximum aggregate amount to be paid in one year | 40,000,000 |
Current maximum annual assessments under NEIL policies | $ 83,000,000 |
Georgia Power | Positive Outcome of Litigation |  |
Jointly Owned Utility Plant Interests [Line Items] |  |
Outstanding claims |  | $ 132,000,000

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