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INCOME TAXES - Reconciliation of Federal Statutory Income Tax Rate (Details) | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Reconciliation of federal statutory income tax rate to effective income tax rate |  |  |
Federal statutory rate | 21.00% | 21.00% | 21.00%
State income tax, net of federal deduction | 2.60% | 6.20% | 5.50%
Employee stock plans' dividend deduction | (0.50%) | (0.50%) | (0.90%)
Non-deductible book depreciation | 0.70% | 0.60% | 0.90%
Flowback of excess deferred income taxes | (9.20%) | (6.60%) | (11.70%)
AFUDC-Equity | (1.10%) | (1.10%) | (1.50%)
Federal PTCs | (1.20%) | 0.00% | 0.00%
ITC amortization | (1.30%) | (1.30%) | (2.20%)
Noncontrolling interests | 0.60% | 0.50% | 0.80%
Leveraged lease impairments and dispositions |  |  | (1.40%)
Other | (0.20%) | 0.00% | (0.10%)
Effective income tax (benefit) rate | 11.40% | 18.80% | 10.40%
Alabama Power |  |  |
Reconciliation of federal statutory income tax rate to effective income tax rate |  |  |
Federal statutory rate | 21.00% | 21.00% | 21.00%
State income tax, net of federal deduction | 5.20% | 4.80% | 4.60%
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.70% | 0.50% | 0.50%
Flowback of excess deferred income taxes | (19.80%) | (1.90%) | (2.60%)
AFUDC-Equity | (1.20%) | (0.80%) | (0.70%)
Federal PTCs | 0.00% | 0.00% | 0.00%
ITC amortization | (0.10%) | (0.10%) | (0.10%)
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions |  |  | 0.00%
Other | (0.20%) | 0.30% | 0.20%
Effective income tax (benefit) rate | 5.60% | 23.80% | 22.90%
Georgia Power |  |  |
Reconciliation of federal statutory income tax rate to effective income tax rate |  |  |
Federal statutory rate | 21.00% | 21.00% | 21.00%
State income tax, net of federal deduction | 1.50% | 6.50% | (5.70%)
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.80% | 0.60% | 3.10%
Flowback of excess deferred income taxes | (2.60%) | (9.60%) | (49.90%)
AFUDC-Equity | (1.20%) | (1.50%) | (6.40%)
Federal PTCs | (1.40%) | 0.00% | 0.00%
ITC amortization | (0.10%) | (0.10%) | (0.40%)
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions |  |  | 0.00%
Other | (0.30%) | 0.00% | (1.90%)
Effective income tax (benefit) rate | 17.70% | 16.90% | (40.20%)
Mississippi Power |  |  |
Reconciliation of federal statutory income tax rate to effective income tax rate |  |  |
Federal statutory rate | 21.00% | 21.00% | 21.00%
State income tax, net of federal deduction | 4.90% | 4.40% | 4.90%
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.40% | 0.30% | 0.40%
Flowback of excess deferred income taxes | (10.20%) | (7.80%) | (15.20%)
AFUDC-Equity | 0.00% | 0.00% | 0.00%
Federal PTCs | 0.00% | 0.00% | 0.00%
ITC amortization | 0.00% | 0.00% | 0.00%
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions |  |  | 0.00%
Other | 0.10% | 0.30% | 0.60%
Effective income tax (benefit) rate | 16.20% | 18.20% | 11.70%
Southern Power |  |  |
Reconciliation of federal statutory income tax rate to effective income tax rate |  |  |
Federal statutory rate | 21.00% | 21.00% | 21.00%
State income tax, net of federal deduction | (0.70%) | 1.90% | (8.00%)
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.00% | 0.00% | 0.00%
Flowback of excess deferred income taxes | 0.00% | 0.00% | 0.00%
AFUDC-Equity | 0.00% | 0.00% | 0.00%
Federal PTCs | (7.40%) | (6.60%) | (4.60%)
ITC amortization | (19.00%) | (17.20%) | (29.70%)
Noncontrolling interests | 11.10% | 8.40% | 13.40%
Leveraged lease impairments and dispositions |  |  | 0.00%
Other | 0.10% | (0.10%) | (0.40%)
Effective income tax (benefit) rate | 5.10% | 7.40% | (8.30%)
Southern Company Gas |  |  |
Reconciliation of federal statutory income tax rate to effective income tax rate |  |  |
Federal statutory rate | 21.00% | 21.00% | 21.00%
State income tax, net of federal deduction | 7.80% | 6.40% | 15.10%
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.00% | 0.00% | 0.00%
Flowback of excess deferred income taxes | (2.60%) | (2.50%) | (2.80%)
AFUDC-Equity | 0.00% | 0.00% | 0.00%
Federal PTCs | 0.00% | 0.00% | 0.00%
ITC amortization | 0.00% | (0.10%) | (0.10%)
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions |  |  | 0.00%
Other | (0.60%) | (0.90%) | 0.60%
Effective income tax (benefit) rate | 25.60% | 23.90% | 33.80%

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