XML 173 R120.htm IDEA: XBRL DOCUMENT
v3.25.0.1

REGULATORY MATTERS - GPC Joint Owner Contracts (Details) - USD ($) $ in Millions | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Oct. 31, 2023 | Jun. 30, 2024 | Dec. 31, 2023 | Dec. 31, 2023 | Dec. 31, 2022
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Agreement with third party, amount of costs over projected forecast to be paid by company |  |  |  |  | 20.00%
Georgia Power |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Pre-tax charge to income |  | $ 7.6 |  | $ 567.0 |
After tax charge to income |  | $ 5.7 |  | $ 424.0 |
Plant Vogtle Units 3 and 4 | Georgia Power |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Remaining share of construction costs, agreement to pay, percentage | 66.00% |  |  |  |
Pre-tax charge to income |  |  | $ 228.0 |  |
After tax charge to income |  |  | $ 170.0 |  |
Plant Vogtle Units 3 and 4 | Georgia Power | MEAG Power |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Agreement with third party, expected cost |  |  |  |  | $ 91.0
Plant Vogtle Units 3 and 4 | Georgia Power | Oglethorpe Power Corporation |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Agreement with third party, expected cost | $ 99.0 |  |  |  |
Plant Vogtle Units 3 and 4 | Georgia Power | Dalton Utilities |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Agreement with third party, expected cost | $ 5.3 |  |  |  |

X
- Definition After Tax Charge To Income + References No definition available. + Details
Name: | so_AfterTaxChargeToIncome
Namespace Prefix: | so_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Pre-Tax Charge To Income + References No definition available. + Details
Name: | so_PreTaxChargeToIncome
Namespace Prefix: | so_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Agreement With Third Party, Construction Costs Over Projected Forecast, To Be Paid, Percentage + References No definition available. + Details
Name: | so_PublicUtilitiesAgreementWithThirdPartyConstructionCostsOverProjectedForecastToBePaidPercentage
Namespace Prefix: | so_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Agreement With Third Party, Expected Cost + References No definition available. + Details
Name: | so_PublicUtilitiesAgreementWithThirdPartyExpectedCost
Namespace Prefix: | so_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Remaining Share of Construction Costs, Agreement To Pay, Percentage + References No definition available. + Details
Name: | so_RemainingShareofConstructionCostsAgreementToPayPercentage
Namespace Prefix: | so_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesGeneralDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=so_GeorgiaPowerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=so_PlantVogtleUnits3And4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=so_MEAGPowerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=so_OglethorpePowerCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=so_DaltonUtilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |