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REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Jan. 01, 2023
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 7,041 | $ 6,523 |  |
Regulatory asset amortization period | 4 years |  |  |
Regulatory asset |  | 66 | $ 216 |
Regulatory liabilities | $ 705 |  |  |
Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 2,356 | 2,720 |  |
Regulatory asset | 70 | 76 | 97 |
Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 6,139 | 5,090 |  |
Regulatory asset |  |  | 83 |
Costs recovered annually | 5 | 5 | 12 |
Regulatory liabilities | $ 827 | 54 |  |
Georgia Power | Plant Vogtle Units 3 and 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 10 years |  |  |
Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 59 | 90 |  |
Regulatory asset | 52 | 44 | $ 36 |
Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (2,252) | (2,225) |  |
Fuel Hedging (Realized And Unrealized) losses | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory liability amortization period | 3 years 6 months |  |  |
Fuel Hedging (Realized And Unrealized) losses | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory liability amortization period | 3 years |  |  |
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory liability amortization period | 4 years |  |  |
Deferred Income Tax Credits |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (4,536) | (4,686) |  |
Deferred Income Tax Credits | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (1,398) | (1,506) |  |
Deferred Income Tax Credits | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (2,149) | (2,161) |  |
Deferred Income Tax Credits | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (219) | (241) |  |
Deferred Income Tax Credits | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (755) | (759) |  |
Other Cost of Removal Obligations |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (1,176) | (287) |  |
Other Cost of Removal Obligations | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 24 | (3) |  |
Other Cost of Removal Obligations | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 816 | (46) |  |
Other Cost of Removal Obligations | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (170) | 0 |  |
Other Cost of Removal Obligations | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (1,846) | (238) |  |
Over Recovered Regulatory Clause Revenues |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (285) | (1,312) |  |
Over Recovered Regulatory Clause Revenues | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (29) | 28 |  |
Over Recovered Regulatory Clause Revenues | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (52) | 617 |  |
Over Recovered Regulatory Clause Revenues | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | (186) |  |
Over Recovered Regulatory Clause Revenues | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (204) | (1,771) |  |
Regulatory liability amortization period | 5 years |  |  |
Reliability reserves |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (188) | (179) |  |
Reliability reserves | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (131) | (143) |  |
Reliability reserves | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Reliability reserves | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (57) | (36) |  |
Reliability reserves | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Storm/Property Damage Reserves |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (122) | (120) |  |
Storm/Property Damage Reserves | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (70) | (76) |  |
Storm/Property Damage Reserves | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Storm/Property Damage Reserves | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (52) | (44) |  |
Storm/Property Damage Reserves | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Nuclear Fuel Disposal Cost Recovery |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (100) |  |  |
Nuclear Fuel Disposal Cost Recovery | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (100) |  |  |
Nuclear Fuel Disposal Cost Recovery | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 |  |  |
Nuclear Fuel Disposal Cost Recovery | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 |  |  |
Nuclear Fuel Disposal Cost Recovery | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 |  |  |
Other Regulatory Liabilities |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | (180) | (333) |  |
Other Regulatory Liabilities | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (28) | (94) |  |
Regulatory liability amortization period | 1 year |  |  |
Other Regulatory Liabilities | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (14) | (23) |  |
Regulatory liability amortization period | 3 years |  |  |
Other Regulatory Liabilities | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (6) | (2) |  |
Regulatory liability amortization period | 1 year |  |  |
Other Regulatory Liabilities | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ (31) | (101) |  |
Regulatory liability amortization period | 20 years |  |  |
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 and 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory liabilities | $ 102 |  |  |
Deferred Income Tax Charges | Southern Company Gas | Plant Vogtle Units 3 and 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory liabilities | 24 |  |  |
AROs |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 5,810 | 5,733 |  |
AROs | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 1,906 | 1,936 |  |
AROs | Alabama Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 64 years |  |  |
AROs | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 3,658 | 3,505 |  |
AROs | Georgia Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 54 years |  |  |
AROs | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 248 | 247 |  |
AROs | Mississippi Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 67 years |  |  |
AROs | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 0 | 0 |  |
AROs | Southern Company Gas | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 85 years |  |  |
Retiree Benefit Plans |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 2,605 | 3,011 |  |
Retiree Benefit Plans | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 680 | 815 |  |
Retiree Benefit Plans | Alabama Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 14 years |  |  |
Retiree Benefit Plans | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 892 | 976 |  |
Retiree Benefit Plans | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 134 | 140 |  |
Retiree Benefit Plans | Mississippi Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 14 years |  |  |
Retiree Benefit Plans | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 44 | 146 |  |
Remaining Net Book Value of Retired Assets |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 1,198 | 1,357 |  |
Remaining Net Book Value of Retired Assets | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 454 | 499 |  |
Remaining Net Book Value of Retired Assets | Alabama Power | Plant Gorgas Units 8, 9, And 10 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 419 |  |  |
Remaining Net Book Value of Retired Assets | Alabama Power | Plant Barry Unit 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 35 |  |  |
Regulatory asset amortization period | 10 years |  |  |
Remaining Net Book Value of Retired Assets | Alabama Power | Maximum | Plant Gorgas Units 8, 9, And 10 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 13 years |  |  |
Remaining Net Book Value of Retired Assets | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 729 | 841 |  |
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Wansley Units 1 and 2 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 418 |  |  |
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 302 |  |  |
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 11 years |  |  |
Remaining Net Book Value of Retired Assets | Georgia Power | Minimum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 1 year |  |  |
Remaining Net Book Value of Retired Assets | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 15 | 17 |  |
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Retail electric revenues |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 10 years |  |  |
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Wholesale electric revenues |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 10 years |  |  |
Remaining Net Book Value of Retired Assets | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 0 | 0 |  |
Deferred Income Tax Charges |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 927 | 897 |  |
Deferred Income Tax Charges | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 264 | 262 |  |
Deferred Income Tax Charges | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 634 | 605 |  |
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 and 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 29 |  |  |
Regulatory asset amortization period | 10 years |  |  |
Regulatory asset | $ 135 |  |  |
Deferred Income Tax Charges | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 27 | 28 |  |
Deferred Income Tax Charges | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Under Recovered Regulatory Clause Revenues |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 167 | 413 |  |
Under Recovered Regulatory Clause Revenues | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 119 | 381 |  |
Under Recovered Regulatory Clause Revenues | Alabama Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 6 years |  |  |
Under Recovered Regulatory Clause Revenues | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 0 | 0 |  |
Regulatory asset amortization period | 2 years |  |  |
Under Recovered Regulatory Clause Revenues | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 17 | 12 |  |
Under Recovered Regulatory Clause Revenues | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 31 | 20 |  |
Fuel Hedging (Realized And Unrealized) losses |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 69 | 270 |  |
Fuel Hedging (Realized And Unrealized) losses | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 23 | 100 |  |
Regulatory asset amortization period |  |  |  | 5 years
Fuel Hedging (Realized And Unrealized) losses | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 29 | 121 |  |
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 17 | 49 |  |
Fuel Hedging (Realized And Unrealized) losses | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Regulatory asset amortization period |  |  |  | 2 years
Deferred Depreciation |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 535 | 270 |  |
Deferred Depreciation | Plant Scherer Units 1 through 3 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 139 |  |  |
Regulatory asset amortization period | 6 years |  |  |
Deferred Depreciation | Plant Bowen Units 1 and 2 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 80 |  |  |
Deferred Depreciation | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 286 | 143 |  |
Deferred Depreciation | Alabama Power | Plant Barry Unit 5 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 114 |  |  |
Deferred Depreciation | Alabama Power | Plant Barry |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 48 |  |  |
Deferred Depreciation | Alabama Power | Plant Gaston Unit 5 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 124 |  |  |
Deferred Depreciation | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 249 | 127 |  |
Deferred Depreciation | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Deferred Depreciation | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Environmental Remediation |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 249 | 255 |  |
Environmental Remediation | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Environmental Remediation | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 16 | 20 |  |
Environmental Remediation | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Environmental Remediation | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 233 | 235 |  |
Loss on Reacquired Debt |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 219 | 238 |  |
Loss on Reacquired Debt | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 32 | 35 |  |
Loss on Reacquired Debt | Alabama Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 23 years |  |  |
Loss on Reacquired Debt | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 183 | 197 |  |
Loss on Reacquired Debt | Georgia Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 28 years |  |  |
Loss on Reacquired Debt | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 4 | 5 |  |
Loss on Reacquired Debt | Mississippi Power | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 17 years |  |  |
Loss on Reacquired Debt | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 0 | 1 |  |
Loss on Reacquired Debt | Southern Company Gas | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 3 years |  |  |
Vacation Pay |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 224 | 217 |  |
Regulatory asset amortization period | 1 year |  |  |
Vacation Pay | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 85 | 83 |  |
Vacation Pay | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 112 | 107 |  |
Vacation Pay | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 12 | 11 |  |
Vacation Pay | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 15 | 16 |  |
Software and Cloud Computing Costs |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 200 | 150 |  |
Regulatory asset amortization period | 5 years |  |  |
Software and Cloud Computing Costs | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 76 | 59 |  |
Regulatory asset amortization period | 10 years |  |  |
Software and Cloud Computing Costs | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 116 | 84 |  |
Software and Cloud Computing Costs | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 4 | 2 |  |
Software and Cloud Computing Costs | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 4 | 5 |  |
Regulatory asset amortization period | 10 years |  |  |
Regulatory Clauses |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 162 | 140 |  |
Regulatory Clauses | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 82 | 112 |  |
Regulatory Clauses | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Regulatory Clauses | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Regulatory Clauses | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 80 | 28 |  |
Storm Damage |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 859 | 92 |  |
Storm Damage | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Storm Damage | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 827 | 54 |  |
Storm Damage | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 32 | 38 |  |
Storm Damage | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Nuclear Outage |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 92 | 83 |  |
Nuclear Outage | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 39 | 50 |  |
Nuclear Outage | Alabama Power | Plant Farley |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 18 months |  |  |
Nuclear Outage | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 53 | 33 |  |
Nuclear Outage | Georgia Power | Maximum | Plant Hatch (nuclear) Units 1 and 2 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 24 months |  |  |
Nuclear Outage | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 0 | 0 |  |
Nuclear Outage | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Long Term Debt Fair Value Adjustment |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 52 | 60 |  |
Long Term Debt Fair Value Adjustment | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Long Term Debt Fair Value Adjustment | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Long Term Debt Fair Value Adjustment | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Long Term Debt Fair Value Adjustment | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 52 | 60 |  |
Long Term Debt Fair Value Adjustment | Southern Company Gas | Maximum |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 14 years |  |  |
Qualifying Repairs Of Natural Gas Distribution Systems |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 53 | 40 |  |
Qualifying Repairs Of Natural Gas Distribution Systems | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Qualifying Repairs Of Natural Gas Distribution Systems | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Qualifying Repairs Of Natural Gas Distribution Systems | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Qualifying Repairs Of Natural Gas Distribution Systems | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 53 | 40 |  |
Qualifying Repairs Of Natural Gas Distribution Systems | Atlanta Gas Light |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 20 years |  |  |
Plant Daniel Units 3 and 4 |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 23 | 25 |  |
Plant Daniel Units 3 and 4 | Retail electric revenues |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 16 |  |  |
Plant Daniel Units 3 and 4 | Wholesale electric revenues |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 8 |  |  |
Plant Daniel Units 3 and 4 | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Plant Daniel Units 3 and 4 | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Plant Daniel Units 3 and 4 | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 23 | 25 |  |
Plant Daniel Units 3 and 4 | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 0 | 0 |  |
Other Regulatory Assets |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | 184 | 189 |  |
Other Regulatory Assets | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 42 | 39 |  |
Regulatory asset amortization period | 19 years |  |  |
Other Regulatory Assets | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 40 | 33 |  |
Regulatory asset amortization period | 10 years |  |  |
Other Regulatory Assets | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 30 | 25 |  |
Regulatory asset amortization period | 10 years |  |  |
Other Regulatory Assets | Southern Company Gas |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 72 | $ 93 |  |
Regulatory asset amortization period | 15 years |  |  |
CCR AROs | Alabama Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 38 years |  |  |
CCR AROs | Georgia Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Regulatory asset amortization period | 3 years |  |  | 4 years
Regulatory Clauses, Amortized Through PEP | Mississippi Power |  |  |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Net regulatory assets | $ 17 |  |  |

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