MRA Tariff, Terms, Counterparty's Electricity Requirements At Delivery Points, Percentage

No definition available.

Name:	so_MRATariffTermsCounterpartysElectricityRequirementsAtDeliveryPointsPercentage
Namespace Prefix:	so_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

MRA Tariff, Terms, Counterparty's Option To Reduce Use Of Services, Percentage

+ References

No definition available.

+ Details

Name:	so_MRATariffTermsCounterpartysOptionToReduceUseOfServicesPercentage
Namespace Prefix:	so_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

MRA Tariff, Terms, Power Supplied To Counterparty Annually

+ References

No definition available.

+ Details

Name:	so_MRATariffTermsPowerSuppliedToCounterpartyAnnually
Namespace Prefix:	so_
Data Type:	dtr-types:powerItemType
Balance Type:	na
Period Type:	instant

- 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_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreasePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=so_MississippiPowerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=so_PerformanceEvaluationPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=so_AdValoremTaxAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=so_MunicipalAndRuralAssociationsTariffMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=so_CooperativeEnergyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Regulatory Matters - MPC (Details) - MISSISSIPPI POWER CO $ in Millions	Jul. 15, 2022 USD ($)	Jun. 07, 2022 USD ($)	Jun. 30, 2022 MW	May 26, 2022
Performance Evaluation Plan
Loss Contingencies [Line Items]
Approved rate increase (decrease)		$ 18
Approved rate increase, percentage		1.90%
Ad Valorem Tax Adjustment
Loss Contingencies [Line Items]
Approved rate increase (decrease)		$ 5
Subsequent Event \| Municipal and Rural Associations Tariff
Loss Contingencies [Line Items]
Requested rate increase (decrease) amount	$ 23
Cooperative Energy
Loss Contingencies [Line Items]
Counterparty's option to decrease services, percentage				2.50%
Counterparty's electricity requirement at MRA delivery points				100.00%
Power being supplied to counterparty \| MW			400