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Schedule III Supplementary Insurance Information (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Supplementary Insurance Information, by Segment |  |  |  |  |  |  |  |
Deferred Acquisition Costs | $ 1,901.3 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts | $ 1,829.2 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts | $ 1,901.3 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts |  | $ 1,829.2 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts |  |  |
Reserves for Future Policy Contract Benefits | 45,929.4 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves | 43,099.1 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves | 45,929.4 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves |  | 43,099.1 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves |  |  |
Unearned Premiums | 396.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums | 413.8 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums | 396.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums |  | 413.8 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums |  |  |
Policy and Contract Benefits | 1,529.3 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable | 1,511.0 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable | 1,529.3 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable |  | 1,511.0 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable |  |  |
Premium Income |  |  | 7,797.2 us-gaap_SupplementaryInsuranceInformationPremiumRevenue |  | 7,624.7 us-gaap_SupplementaryInsuranceInformationPremiumRevenue |  | 7,716.1 us-gaap_SupplementaryInsuranceInformationPremiumRevenue |
Net Investment Income |  |  | 2,477.4 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome | [1] | 2,492.1 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome | [1] | 2,515.2 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome | [1]
Benefits and Change in Reserves for Future Benefits |  |  | 7,310.8 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense | [2] | 6,595.7 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense | [2] | 6,722.2 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense |
Amortization of Deferred Acquisition Costs |  |  | 440.8 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts |  | 418.9 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts |  | 378.7 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts |
All Other Expenses |  |  | 2,230.9 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense | [3] | 2,134.0 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense | [3] | 2,165.0 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense | [3]
Reserve Increase for Long-term Care | 698.2 unm_ReserveIncreaseforLongtermCareBeforeTax |  | 698.2 unm_ReserveIncreaseforLongtermCareBeforeTax |  |  |  |  |
Unclaimed Death Benefit Reserve Increase Before Taxes |  | 95.5 unm_UnclaimedDeathBenefitReserveIncreaseDecreaseBeforeTaxes |  |  | 95.5 unm_UnclaimedDeathBenefitReserveIncreaseDecreaseBeforeTaxes |  |  |
Waiver of Premium Benefit Reserve Increase (Decrease) Before Tax |  | (85.0)unm_WaiverofPremiumBenefitReserveIncreaseDecreaseBeforeTax |  |  |  |  |  |
Unum U.S. |  |  |  |  |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |  |  |  |  |
Deferred Acquisition Costs | 1,096.5 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 1,051.5 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 1,096.5 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 1,051.5 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  |  |
Reserves for Future Policy Contract Benefits | 11,828.0 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 11,788.4 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 11,828.0 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 11,788.4 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  |  |
Unearned Premiums | 46.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 47.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 46.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 47.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  |  |
Policy and Contract Benefits | 953.7 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 889.1 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | 953.7 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 889.1 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  |  |
Premium Income |  |  | 4,659.7 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 4,517.1 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 4,456.5 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |
Net Investment Income |  |  | 890.3 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [1] | 929.6 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [1] | 952.3 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [1]
Benefits and Change in Reserves for Future Benefits |  |  | 3,288.1 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [2] | 3,222.4 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [2] | 3,238.6 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |
Amortization of Deferred Acquisition Costs |  |  | 248.1 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 230.0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  | 196.5 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |
All Other Expenses |  |  | 1,279.6 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [3] | 1,254.0 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [3] | 1,251.2 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [3]
Premiums Written |  |  | 3,144.1 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [4] | 3,068.0 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [4] | 3,045.0 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember | [4]
Unclaimed Death Benefit Reserve Increase Before Taxes |  |  |  |  | 75.4 unm_UnclaimedDeathBenefitReserveIncreaseDecreaseBeforeTaxes / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  |  |
Waiver of Premium Benefit Reserve Increase (Decrease) Before Tax |  |  |  |  | 85.0 unm_WaiverofPremiumBenefitReserveIncreaseDecreaseBeforeTax / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUsMember |  |  |
Unum U.K. |  |  |  |  |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |  |  |  |  |
Deferred Acquisition Costs | 30.4 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 34.3 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 30.4 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 34.3 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  |  |
Reserves for Future Policy Contract Benefits | 2,596.7 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 2,594.3 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 2,596.7 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 2,594.3 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  |  |
Unearned Premiums | 130.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 139.3 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 130.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 139.3 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  |  |
Policy and Contract Benefits | 127.6 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 160.0 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | 127.6 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 160.0 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  |  |
Premium Income |  |  | 607.2 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 556.6 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 694.6 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |
Net Investment Income |  |  | 151.0 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [1] | 148.5 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [1] | 170.8 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [1]
Benefits and Change in Reserves for Future Benefits |  |  | 431.0 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [2] | 413.3 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [2] | 541.4 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |
Amortization of Deferred Acquisition Costs |  |  | 12.5 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 14.7 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |  | 15.7 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember |
All Other Expenses |  |  | 166.9 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [3] | 145.2 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [3] | 177.1 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [3]
Premiums Written |  |  | 479.9 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [4] | 448.1 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [4] | 466.3 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_UnumUkMember | [4]
Colonial Life |  |  |  |  |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |  |  |  |  |
Deferred Acquisition Costs | 774.4 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 743.4 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 774.4 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 743.4 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  |  |
Reserves for Future Policy Contract Benefits | 1,919.7 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 1,815.6 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 1,919.7 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 1,815.6 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  |  |
Unearned Premiums | 30.8 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 30.0 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 30.8 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 30.0 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  |  |
Policy and Contract Benefits | 191.4 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 193.7 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | 191.4 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 193.7 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  |  |
Premium Income |  |  | 1,273.7 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 1,232.2 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 1,194.5 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |
Net Investment Income |  |  | 146.7 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [1] | 145.4 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [1] | 138.6 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [1]
Benefits and Change in Reserves for Future Benefits |  |  | 660.6 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [2] | 667.0 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [2] | 627.3 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |
Amortization of Deferred Acquisition Costs |  |  | 180.2 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 174.2 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  | 166.5 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |
All Other Expenses |  |  | 279.5 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [3] | 271.8 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [3] | 265.3 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [3]
Premiums Written |  |  | 1,042.7 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [4] | 1,011.8 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [4] | 986.3 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember | [4]
Unclaimed Death Benefit Reserve Increase Before Taxes |  |  |  |  | 20.1 unm_UnclaimedDeathBenefitReserveIncreaseDecreaseBeforeTaxes / us-gaap_StatementBusinessSegmentsAxis = unm_ColonialLifeMember |  |  |
Closed Block |  |  |  |  |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |  |  |  |  |
Deferred Acquisition Costs | 0 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 0 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 0 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 0 us-gaap_SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  |  |
Reserves for Future Policy Contract Benefits | 29,585.0 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 26,900.8 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 29,585.0 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 26,900.8 us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  |  |
Unearned Premiums | 188.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 196.9 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 188.6 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 196.9 us-gaap_SupplementaryInsuranceInformationUnearnedPremiums / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  |  |
Policy and Contract Benefits | 256.6 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 268.2 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | 256.6 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 268.2 us-gaap_SupplementaryInsuranceInformationOtherPolicyClaimsAndBenefitsPayable / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  |  |
Premium Income |  |  | 1,256.6 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 1,318.8 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 1,370.5 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |
Net Investment Income |  |  | 1,284.1 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [1] | 1,272.3 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [1] | 1,230.5 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [1]
Benefits and Change in Reserves for Future Benefits |  |  | 2,931.1 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [2] | 2,293.0 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [2] | 2,314.9 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |
Amortization of Deferred Acquisition Costs |  |  | 0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  | 0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |
All Other Expenses |  |  | 277.0 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [3] | 282.6 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [3] | 290.7 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [3]
Premiums Written |  |  | 1,248.6 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [4] | 1,307.0 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [4] | 1,358.6 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember | [4]
Reserve Increase for Long-term Care |  |  | 698.2 unm_ReserveIncreaseforLongtermCareBeforeTax / us-gaap_StatementBusinessSegmentsAxis = unm_ClosedBlockMember |  |  |  |  |
Corporate and Other Segment |  |  |  |  |  |  |  |
Supplementary Insurance Information, by Segment |  |  |  |  |  |  |  |
Premium Income |  |  | 0 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  | 0 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  | 0 us-gaap_SupplementaryInsuranceInformationPremiumRevenue / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |
Net Investment Income |  |  | 5.3 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [1] | (3.7)us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [1] | 23.0 us-gaap_SupplementaryInsuranceInformationNetInvestmentIncome / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [1]
Benefits and Change in Reserves for Future Benefits |  |  | 0 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [2] | 0 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [2] | 0 us-gaap_SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |
Amortization of Deferred Acquisition Costs |  |  | 0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  | 0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  | 0 us-gaap_SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |
All Other Expenses |  |  | 227.9 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [3] | 180.4 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [3] | 180.7 us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [3]
Premiums Written |  |  | 0 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [4] | 0 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [4] | 0 us-gaap_SupplementaryInsuranceInformationPremiumsWritten / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | [4]
Non-operating retirement related loss due to settlement |  |  | $ 64.4 us-gaap_OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  |  |  |  |
[1] | Net investment income is allocated based upon segmentation. Each segment has its own specifically identified assets and receives the investment income generated by those assets.
[2] | Included in 2014 is a reserve charge of $698.2 million in the Closed Block segment related to our long-term care business. Included in 2013 are unclaimed death benefits reserve increases of $75.4 million in the Unum US segment and $20.1 million in the Colonial Life segment and a group life waiver of premium benefit reserve reduction of $85.0 million in the Unum US segment.
[3] | Includes commissions; interest and debt expense; deferral of acquisition costs; compensation expense; non-operating retirement related loss, which in 2014 included a settlement loss of $64.4 million in the Corporate segment related to a pension plan amendment; and other expenses. Where not directly attributable to a segment, expenses are generally allocated based on activity levels, time information, and usage statistics.
[4] | Excludes life insurance.

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