XML 183 R130.htm IDEA: XBRL DOCUMENT
v3.25.0.1

REGULATORY MATTERS - GAS Schedule of Infrastructure Replacement Programs and Capital Projects (Details) - Southern Company Gas $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) mi | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Public Utilities, General Disclosures [Line Items] |  |  |
Capital Expenditures in 2024 | $ 186 |  |
Capital Expenditures Since Project Inception | $ 868 |  |
Pipe Installed Since Project Inception (in miles) | mi | 651 |  |
Scope of Program (in miles) | mi | 1,011 |  |
SAVE |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Capital Expenditures in 2024 | $ 75 |  |
Capital Expenditures Since Project Inception | $ 561 |  |
Pipe Installed Since Project Inception (in miles) | mi | 598 |  |
Scope of Program (in miles) | mi | 938 |  |
Program Duration | 18 years |  |
System Reinforcement Rider |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Capital Expenditures in 2024 | $ 99 | $ 104 | $ 76
Capital Expenditures Since Project Inception | $ 279 |  |
Pipe Installed Since Project Inception (in miles) | mi | 29 |  |
Program Duration | 6 years |  |
Pipeline Replacement Program |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Capital Expenditures in 2024 | $ 12 |  |
Capital Expenditures Since Project Inception | $ 28 |  |
Pipe Installed Since Project Inception (in miles) | mi | 24 |  |
Scope of Program (in miles) | mi | 73 |  |
Program Duration | 7 years |  |

X
- Definition Public Utilities, Infrastructure Replacement Programs And Capital Projects, Expenditures + References No definition available. + Details
Name: | so_PublicUtilitiesInfrastructureReplacementProgramsAndCapitalProjectsExpenditures
Namespace Prefix: | so_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Infrastructure Replacement Programs And Capital Projects, Expenditures Since Project Inception + References No definition available. + Details
Name: | so_PublicUtilitiesInfrastructureReplacementProgramsAndCapitalProjectsExpendituresSinceProjectInception
Namespace Prefix: | so_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Infrastructure Replacement Programs And Capital Projects, Pipe Installed Since Project Inception + References No definition available. + Details
Name: | so_PublicUtilitiesInfrastructureReplacementProgramsAndCapitalProjectsPipeInstalledSinceProjectInception
Namespace Prefix: | so_
Data Type: | dtr-types1:lengthItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Infrastructure Replacement Programs And Capital Projects, Program Duration + References No definition available. + Details
Name: | so_PublicUtilitiesInfrastructureReplacementProgramsAndCapitalProjectsProgramDuration
Namespace Prefix: | so_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Infrastructure Replacement Programs And Capital Projects, Scope Of Program + References No definition available. + Details
Name: | so_PublicUtilitiesInfrastructureReplacementProgramsAndCapitalProjectsScopeOfProgram
Namespace Prefix: | so_
Data Type: | dtr-types1:lengthItemType
Balance Type: | na
Period Type: | instant

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_SouthernCompanyGasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | so_ProgramAxis=so_SAVEMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | so_ProgramAxis=so_SystemReinforcementRiderMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | so_ProgramAxis=so_PipelineReplacementProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |