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INCOME TAXES - Reconciliation of Federal Statutory Income Tax Rate (Details) | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
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 | 5.50% | 2.80% | 4.90%
Employee stock plans' dividend deduction | (0.90%) | (0.70%) | (0.40%)
Non-deductible book depreciation | 0.90% | 0.70% | 0.30%
Flowback of excess deferred income taxes | (11.70%) | (8.80%) | (2.10%)
AFUDC-Equity | (1.50%) | (0.80%) | (0.40%)
ITC basis difference |  |  | (0.10%)
Federal PTCs | 0.00% | 0.00% |
Amortization of ITC | (2.20%) | (1.60%) | (0.80%)
Tax impact from sale of subsidiaries |  |  | 5.10%
Noncontrolling interests | 0.80% | 0.00% | 0.00%
Leveraged lease impairments and dispositions | (1.40%) | (1.60%) |
Other | (0.10%) | 0.20% | 0.00%
Effective income tax (benefit) rate | 10.40% | 11.20% | 27.50%
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 | 4.60% | 5.00% | 4.90%
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.50% | 0.60% | 0.60%
Flowback of excess deferred income taxes | (2.60%) | (3.10%) | (5.30%)
AFUDC-Equity | (0.70%) | (0.60%) | (0.80%)
ITC basis difference |  |  | 0.00%
Federal PTCs | 0.00% | 0.00% |
Amortization of ITC | (0.10%) | (0.10%) | (0.10%)
Tax impact from sale of subsidiaries |  |  | 0.00%
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions | 0.00% | 0.00% |
Other | 0.20% | (0.30%) | (0.40%)
Effective income tax (benefit) rate | 22.90% | 22.50% | 19.90%
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 | (5.70%) | 0.50% | 1.00%
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 3.10% | 0.80% | 0.50%
Flowback of excess deferred income taxes | (49.90%) | (12.00%) | 0.00%
AFUDC-Equity | (6.40%) | (1.10%) | (0.60%)
ITC basis difference |  |  | 0.00%
Federal PTCs | 0.00% | 0.00% |
Amortization of ITC | (0.40%) | (0.10%) | (0.10%)
Tax impact from sale of subsidiaries |  |  | 0.00%
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions | 0.00% | 0.00% |
Other | (1.90%) | (0.30%) | (0.30%)
Effective income tax (benefit) rate | (40.20%) | 8.80% | 21.50%
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% | 4.80% | 4.30%
Employee stock plans' dividend deduction | 0.00% | 0.00% | 0.00%
Non-deductible book depreciation | 0.40% | 0.50% | 0.40%
Flowback of excess deferred income taxes | (15.20%) | (18.50%) | (12.60%)
AFUDC-Equity | 0.00% | (0.10%) | (0.10%)
ITC basis difference |  |  | 0.00%
Federal PTCs | 0.00% | 0.00% |
Amortization of ITC | 0.00% | (0.10%) | (0.10%)
Tax impact from sale of subsidiaries |  |  | 0.00%
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions | 0.00% | 0.00% |
Other | 0.60% | 0.90% | 4.90%
Effective income tax (benefit) rate | 11.70% | 8.50% | 17.80%
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 | (8.00%) | 2.70% | 4.00%
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%
ITC basis difference |  |  | (1.90%)
Federal PTCs | (4.60%) | (2.50%) |
Amortization of ITC | (29.70%) | (22.10%) | (16.10%)
Tax impact from sale of subsidiaries |  |  | (27.60%)
Noncontrolling interests | 13.40% | 3.10% | 0.80%
Leveraged lease impairments and dispositions | 0.00% | 0.00% |
Other | (0.40%) | (0.90%) | (0.60%)
Effective income tax (benefit) rate | (8.30%) | 1.30% | (20.40%)
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 | 15.10% | 4.00% | 6.10%
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 | (2.80%) | (2.70%) | (6.00%)
AFUDC-Equity | 0.00% | 0.00% | 0.00%
ITC basis difference |  |  | 0.00%
Federal PTCs | 0.00% | 0.00% |
Amortization of ITC | (0.10%) | (0.10%) | (0.10%)
Tax impact from sale of subsidiaries |  |  | (1.40%)
Noncontrolling interests | 0.00% | 0.00% | 0.00%
Leveraged lease impairments and dispositions | 0.00% | 0.00% |
Other | 0.60% | 0.50% | (1.40%)
Effective income tax (benefit) rate | 33.80% | 22.70% | 18.20%

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