XML 250 R206.htm IDEA: XBRL DOCUMENT
v3.22.0.1

STOCK COMPENSATION - Schedule of Employees Participating in Stock-Based Compensation Programs (Details) | Dec. 31, 2021 employee
--- | ---
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of employees | 1,728
Alabama Power |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of employees | 241
Georgia Power |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of employees | 271
Mississippi Power |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of employees | 70
Southern Power |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of employees | 45
Southern Company Gas |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of employees | 173

X
- Definition Number Of Employees Participating in Stock Option and Performance Share Units Program + References No definition available. + Details
Name: | so_NumberOfEmployeesParticipatinginStockOptionandPerformanceShareUnitsProgram
Namespace Prefix: | so_
Data Type: | xbrli:integerItemType
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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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

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

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

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