XML 139 R97.htm IDEA: XBRL DOCUMENT
v3.24.0.1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Other Intangible Assets (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | $ 669 | $ 671
Accumulated Amortization | (376) | (340)
Other Intangible Assets, Net | 293 | 331
Intangible assets, gross | 744 | 746
Intangible assets, net | 368 | 406
FCC licenses |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 75 | 75
Accumulated Amortization | 0 | 0
Other Intangible Assets, Net | 75 | 75
Customer relationships |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 212 | 212
Accumulated Amortization | (172) | (162)
Other Intangible Assets, Net | 40 | 50
Trade names |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 64 | 64
Accumulated Amortization | (53) | (44)
Other Intangible Assets, Net | 11 | 20
PPA fair value adjustments |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 390 | 390
Accumulated Amortization | (148) | (129)
Other Intangible Assets, Net | 242 | 261
Other |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 3 | 5
Accumulated Amortization | (3) | (5)
Other Intangible Assets, Net | 0 | 0
Southern Power |  |
Finite-Lived Intangible Assets [Line Items] |  |
Accumulated Amortization | (148) | (129)
Southern Power | PPA fair value adjustments |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 390 | 390
Accumulated Amortization | (148) | (129)
Other Intangible Assets, Net | 242 | 261
Southern Company Gas |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 182 | 182
Accumulated Amortization | (166) | (156)
Other Intangible Assets, Net | 16 | 26
Intangible assets, net | 16 | 26
Southern Company Gas | Customer relationships |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 156 | 156
Accumulated Amortization | (145) | (139)
Other Intangible Assets, Net | 11 | 17
Southern Company Gas | Trade names |  |
Finite-Lived Intangible Assets [Line Items] |  |
Gross Carrying Amount | 26 | 26
Accumulated Amortization | (21) | (17)
Other Intangible Assets, Net | $ 5 | $ 9

X
- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(16)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 928 -SubTopic 340 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483147/928-340-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 926 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483154/926-20-50-5 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 926 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483154/926-20-50-5 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before accumulated amortization of intangible assets, excluding goodwill. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(15)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_IntangibleAssetsGrossExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph ((a)(1),(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482686/350-30-45-1 + Details
Name: | us-gaap_IntangibleAssetsNetExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis=so_FCCLicensesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TradeNamesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=so_PPAFairValueAdjustmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_OtherIntangibleAssetsMember
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: |