XML 51 R41.htm IDEA: XBRL DOCUMENT
v3.23.2

Fair Value of Financial Instruments Additional Information (Detail) - USD ($) $ in Millions | Jun. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Ceded Policy Loans | $ 3,199.9 | $ 3,312.5
Fair Value, Inputs, Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 24.20% |
Fair Value, Inputs, Level 2 | Pricing Service |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 60.10% |
Fair Value, Inputs, Level 2 | Other Observable Market Data |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 14.90% |
Fair Value Inputs Other Than Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 75.80% |
Fair Value Inputs Level 2 Or Level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis |  |
Percentage of Total Fair Value of Fixed Maturities Securities | 0.80% |

X
- Definition Available For Sale Securities, Percent Of Total Fair Value + References No definition available. + Details
Name: | unm_AvailableForSaleSecuritiesPercentOfTotalFairValue
Namespace Prefix: | unm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loans ceded to reinsurers. These loans use insurance policy funds such as cash surrender values as collateral. + References No definition available. + Details
Name: | unm_PolicyLoansCededtoReinsurers
Namespace Prefix: | unm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-3 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | unm_FairValueAssetsAndLiabilitiesComponentsAxis=unm_PricingServiceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | unm_FairValueAssetsAndLiabilitiesComponentsAxis=unm_OtherObservableMarketDataMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | unm_HeirarchyLevelCombinationAxis=unm_FairValueInputsOtherThanLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | unm_HeirarchyLevelCombinationAxis=unm_FairValueInputsLevel2OrLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |