XML 143 R115.htm IDEA: XBRL DOCUMENT
v3.23.2

Derivatives - Schedule of Interest Rate Derivatives (Details) - Interest rate derivatives $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2023 USD ($)
Derivative [Line Items] |
Notional Amount | $ 2,150
Fair Value Gain (Loss) | (300)
Southern Company parent(a) | Fair Value Hedges of Existing Debt | March 2028 |
Derivative [Line Items] |
Notional Amount | $ 400
Interest Rate Received | 1.75%
Fair Value Gain (Loss) | $ (56)
Southern Company parent(a) | Fair Value Hedges of Existing Debt | April 2030 |
Derivative [Line Items] |
Notional Amount | $ 1,000
Interest Rate Received | 3.70%
Fair Value Gain (Loss) | $ (160)
SOUTHERN Co GAS | Cash Flow Hedges of Forecasted Debt |
Derivative [Line Items] |
Notional Amount | $ 250
Weighted Average Interest Rate Paid | 3.40%
Fair Value Gain (Loss) | $ 4
SOUTHERN Co GAS | Fair Value Hedges of Existing Debt |
Derivative [Line Items] |
Notional Amount | $ 500
Interest Rate Received | 1.75%
Fair Value Gain (Loss) | $ (88)
LIBOR | Southern Company parent(a) | Fair Value Hedges of Existing Debt | March 2028 |
Derivative [Line Items] |
Weighted Average Interest Rate Paid | 0.68%
LIBOR | Southern Company parent(a) | Fair Value Hedges of Existing Debt | April 2030 |
Derivative [Line Items] |
Weighted Average Interest Rate Paid | 2.36%
LIBOR | SOUTHERN Co GAS | Fair Value Hedges of Existing Debt |
Derivative [Line Items] |
Weighted Average Interest Rate Paid | 0.38%

X
- Definition Fair value gain (Loss). + References No definition available. + Details
Name: | so_FairValueGainLoss
Namespace Prefix: | so_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Notional amount of interest rate derivatives, interest rate paid. + References No definition available. + Details
Name: | so_NotionalAmountofInterestRateDerivativesInterestRatePaid
Namespace Prefix: | so_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Notional amount of interest rate derivatives, interest rate received. + References No definition available. + Details
Name: | so_NotionalAmountofInterestRateDerivativesInterestRateReceived
Namespace Prefix: | so_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payments on the derivative liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5C Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column D)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column D)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5A Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column A)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5B Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A + Details
Name: | us-gaap_DerivativeLiabilityNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=so_FairValueHedgesOfExistingDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | so_HedgingMaturityDateAxis=so_HedgingMaturityDateOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | so_HedgingMaturityDateAxis=so_HedgingMaturityDateTwoMember
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: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=so_CashFlowHedgesOfExistingDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=so_LIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |