XML 27 R42.htm IDEA: XBRL DOCUMENT v2.4.1.9
Mortgage Loans by Property Type and Geographic Region (Detail) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Mortgage Loans on Real Estate    
Mortgage Loans $ 1,896.5us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet $ 1,856.6us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
Percent of Total 100.00%unm_PercentageOfLoanPortfolio 100.00%unm_PercentageOfLoanPortfolio
New England    
Mortgage Loans on Real Estate    
Mortgage Loans 104.4us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_NewEnglandMember		 105.6us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_NewEnglandMember
Percent of Total 5.50%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_NewEnglandMember		 5.70%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_NewEnglandMember
Middle Atlantic    
Mortgage Loans on Real Estate    
Mortgage Loans 177.9us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_MiddleAtlanticMember		 179.4us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_MiddleAtlanticMember
Percent of Total 9.40%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_MiddleAtlanticMember		 9.70%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_MiddleAtlanticMember
East North Central    
Mortgage Loans on Real Estate    
Mortgage Loans 209.0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_EastNorthCentralMember		 210.6us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_EastNorthCentralMember
Percent of Total 11.00%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_EastNorthCentralMember		 11.40%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_EastNorthCentralMember
West North Central    
Mortgage Loans on Real Estate    
Mortgage Loans 164.3us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_WestNorthCentralMember		 166.2us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_WestNorthCentralMember
Percent of Total 8.70%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_WestNorthCentralMember		 8.90%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_WestNorthCentralMember
South Atlantic    
Mortgage Loans on Real Estate    
Mortgage Loans 446.8us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_SouthAtlanticMember		 453.6us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_SouthAtlanticMember
Percent of Total 23.50%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_SouthAtlanticMember		 24.40%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_SouthAtlanticMember
East South Central    
Mortgage Loans on Real Estate    
Mortgage Loans 80.8us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_EastSouthCentralMember		 75.3us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_EastSouthCentralMember
Percent of Total 4.30%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_EastSouthCentralMember		 4.10%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_EastSouthCentralMember
West South Central    
Mortgage Loans on Real Estate    
Mortgage Loans 213.7us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_WestSouthCentralMember		 215.6us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_WestSouthCentralMember
Percent of Total 11.30%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_WestSouthCentralMember		 11.60%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_WestSouthCentralMember
Mountain    
Mortgage Loans on Real Estate    
Mortgage Loans 165.2us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_MountainMember		 116.0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_MountainMember
Percent of Total 8.70%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_MountainMember		 6.20%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_MountainMember
Pacific    
Mortgage Loans on Real Estate    
Mortgage Loans 334.4us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_PacificMember		 334.3us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ invest_InvestmentGeographicRegionAxis
= unm_PacificMember
Percent of Total 17.60%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_PacificMember		 18.00%unm_PercentageOfLoanPortfolio
/ invest_InvestmentGeographicRegionAxis
= unm_PacificMember
Apartment    
Mortgage Loans on Real Estate    
Mortgage Loans 118.0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_ApartmentBuildingMember		 110.1us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_ApartmentBuildingMember
Percent of Total 6.20%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_ApartmentBuildingMember		 5.90%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_ApartmentBuildingMember
Industrial    
Mortgage Loans on Real Estate    
Mortgage Loans 523.7us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember		 542.9us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
Percent of Total 27.60%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember		 29.20%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_IndustrialPropertyMember
Office    
Mortgage Loans on Real Estate    
Mortgage Loans 819.3us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_OfficeBuildingMember		 794.0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_OfficeBuildingMember
Percent of Total 43.20%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_OfficeBuildingMember		 42.80%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_OfficeBuildingMember
Retail    
Mortgage Loans on Real Estate    
Mortgage Loans $ 435.5us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_RetailSiteMember		 $ 409.6us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_RetailSiteMember
Percent of Total 23.00%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_RetailSiteMember		 22.10%unm_PercentageOfLoanPortfolio
/ us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis
= us-gaap_RetailSiteMember