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VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
May 31, 2019 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Provision for uncollectible accounts: |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | $ 118 | $ 49 | $ 50
Charged to Income |  | 51 | 78 | 68
Charged to Other Accounts |  | (23) | 27 | 0
Deductions |  | 68 | 36 | 69
Balance at End of Period |  | 78 | 118 | 49
Tax valuation allowance (net state) |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 112 | 113 | 100
Charged to Income |  | 57 | 0 | 13
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 0 | 1 | 0
Balance at End of Period |  | 169 | 112 | 113
Alabama Power | Provision for uncollectible accounts: |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 43 | 22 | 10
Charged to Income |  | (7) | 25 | 24
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 22 | 4 | 12
Balance at End of Period |  | 14 | 43 | 22
Georgia Power | Provision for uncollectible accounts: |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 26 | 2 | 2
Charged to Income |  | 16 | 14 | 13
Charged to Other Accounts |  | (23) | 23 | 0
Deductions |  | 17 | 13 | 13
Balance at End of Period |  | 2 | 26 | 2
Georgia Power | Tax valuation allowance (net state) |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 28 | 28 | 33
Charged to Income |  | 30 | 0 | (5)
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 0 | 0 | 0
Balance at End of Period |  | 58 | 28 | 28
Mississippi Power | Provision for uncollectible accounts: |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 1 | 1 | 1
Charged to Income |  | 1 | 1 | 2
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 1 | 1 | 2
Balance at End of Period |  | 1 | 1 | 1
Mississippi Power | Tax valuation allowance (net state) |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 32 | 32 | 32
Charged to Income |  | 0 | 0 | 0
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 0 | 0 | 0
Balance at End of Period |  | 32 | 32 | 32
Southern Power | Provision for uncollectible accounts: |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 0 | 0 | 0
Charged to Income |  | 5 | 0 | 0
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 0 | 0 | 0
Balance at End of Period |  | 5 | 0 | 0
Southern Power | Tax valuation allowance (net state) |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 27 | 29 | 22
Charged to Income |  | (6) | (1) | 7
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 0 | 1 | 0
Balance at End of Period |  | 21 | 27 | 29
Southern Company Gas | Provision for uncollectible accounts: |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 40 | 18 | 30
Charged to Income |  | 26 | 35 | 29
Charged to Other Accounts |  | 0 | 4 | 0
Deductions |  | 27 | 17 | 41
Balance at End of Period |  | 39 | 40 | 18
Southern Company Gas | Tax valuation allowance (net state) |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Period |  | 4 | 4 | 12
Charged to Income |  | 3 | 0 | (8)
Charged to Other Accounts |  | 0 | 0 | 0
Deductions |  | 0 | 0 | 0
Balance at End of Period |  | 7 | $ 4 | 4
Triton | Southern Company Gas |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Reversal of federal income tax valuation allowance | $ 13 |  |  | 13
State and Local Jurisdiction | Georgia Power |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Valuation allowance |  | $ 58 |  |
State and Local Jurisdiction | Southern Company Gas |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Valuation allowance |  |  |  | $ 5

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