| | | | | | | | | | | | | | | | | | | | | |
<?xml version="1.0" encoding="windows-1252"?> |
<FilingSummary xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> |
| <Version> 2.4.0.8 </Version> |
| <ProcessingTime/> |
| <ReportFormat> Html </ReportFormat> |
| <ContextCount> 947 </ContextCount> |
| <ElementCount> 735 </ElementCount> |
| <EntityCount> 1 </EntityCount> |
| <FootnotesReported> true </FootnotesReported> |
| <SegmentCount> 216 </SegmentCount> |
| <ScenarioCount> 0 </ScenarioCount> |
| <TuplesReported> false </TuplesReported> |
| <UnitCount> 7 </UnitCount> |
| <MyReports> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R1.htm </HtmlFileName> |
| | | <LongName> 0001000 - Document - Document and Entity Information </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DocumentAndEntityInformation </Role> |
| | | <ShortName> Document and Entity Information </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> true </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R2.htm </HtmlFileName> |
| | | <LongName> 1001000 - Statement - CONSOLIDATED BALANCE SHEETS </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedBalanceSheets </Role> |
| | | <ShortName> CONSOLIDATED BALANCE SHEETS </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R3.htm </HtmlFileName> |
| | | <LongName> 1001501 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedBalanceSheetsParenthetical </Role> |
| | | <ShortName> CONSOLIDATED BALANCE SHEETS (Parenthetical) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R4.htm </HtmlFileName> |
| | | <LongName> 1002000 - Statement - CONSOLIDATED STATEMENTS OF INCOME </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedStatementsOfIncome </Role> |
| | | <ShortName> CONSOLIDATED STATEMENTS OF INCOME </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R5.htm </HtmlFileName> |
| | | <LongName> 1003000 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedStatementsOfComprehensiveIncome </Role> |
| | | <ShortName> CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R6.htm </HtmlFileName> |
| | | <LongName> 1003500 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical </Role> |
| | | <ShortName> CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R7.htm </HtmlFileName> |
| | | <LongName> 1004000 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedStatementsOfStockholdersEquity </Role> |
| | | <ShortName> CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R8.htm </HtmlFileName> |
| | | <LongName> 1004500 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedStatementsOfStockholdersEquityParenthetical </Role> |
| | | <ShortName> CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R9.htm </HtmlFileName> |
| | | <LongName> 1005000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ConsolidatedStatementsOfCashFlows </Role> |
| | | <ShortName> CONSOLIDATED STATEMENTS OF CASH FLOWS </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R10.htm </HtmlFileName> |
| | | <LongName> 2106100 - Disclosure - Significant Accounting Policies </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SignificantAccountingPolicies </Role> |
| | | <ShortName> Significant Accounting Policies </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R11.htm </HtmlFileName> |
| | | <LongName> 2107100 - Disclosure - Fair Values of Financial Instruments </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/FairValuesOfFinancialInstruments </Role> |
| | | <ShortName> Fair Values of Financial Instruments </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R12.htm </HtmlFileName> |
| | | <LongName> 2108100 - Disclosure - Investments </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/Investments </Role> |
| | | <ShortName> Investments </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R13.htm </HtmlFileName> |
| | | <LongName> 2109100 - Disclosure - Derivative Financial Instruments </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DerivativeFinancialInstruments </Role> |
| | | <ShortName> Derivative Financial Instruments </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R14.htm </HtmlFileName> |
| | | <LongName> 2110100 - Disclosure - Accumulated Other Comprehensive Income </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/AccumulatedOtherComprehensiveIncome </Role> |
| | | <ShortName> Accumulated Other Comprehensive Income </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R15.htm </HtmlFileName> |
| | | <LongName> 2110100 - Disclosure - Liability for Unpaid Claims </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LiabilityForUnpaidClaims </Role> |
| | | <ShortName> Liability for Unpaid Claims </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R16.htm </HtmlFileName> |
| | | <LongName> 2112100 - Disclosure - Income Tax </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/IncomeTax </Role> |
| | | <ShortName> Income Tax </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R17.htm </HtmlFileName> |
| | | <LongName> 2113100 - Disclosure - Debt </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/Debt </Role> |
| | | <ShortName> Debt </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R18.htm </HtmlFileName> |
| | | <LongName> 2114100 - Disclosure - Employee Benefit Plans </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlans </Role> |
| | | <ShortName> Employee Benefit Plans </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R19.htm </HtmlFileName> |
| | | <LongName> 2115100 - Disclosure - Stockholders' Equity and Earnings Per Common Share </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockholdersEquityAndEarningsPerCommonShare </Role> |
| | | <ShortName> Stockholders' Equity and Earnings Per Common Share </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R20.htm </HtmlFileName> |
| | | <LongName> 2116100 - Disclosure - Stock-Based Compensation </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockBasedCompensation </Role> |
| | | <ShortName> Stock-Based Compensation </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R21.htm </HtmlFileName> |
| | | <LongName> 2117100 - Disclosure - Reinsurance </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/Reinsurance </Role> |
| | | <ShortName> Reinsurance </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R22.htm </HtmlFileName> |
| | | <LongName> 2118100 - Disclosure - Segment Information </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SegmentInformation </Role> |
| | | <ShortName> Segment Information </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R23.htm </HtmlFileName> |
| | | <LongName> 2119100 - Disclosure - Commitments and Contingent Liabilities </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/CommitmentsAndContingentLiabilities </Role> |
| | | <ShortName> Commitments and Contingent Liabilities </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R24.htm </HtmlFileName> |
| | | <LongName> 2120101 - Disclosure - Statutory Financial Information </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StatutoryFinancialInformation </Role> |
| | | <ShortName> Statutory Financial Information </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R25.htm </HtmlFileName> |
| | | <LongName> 2121101 - Disclosure - Unaudited Quarterly Results </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/UnauditedQuarterlyResults </Role> |
| | | <ShortName> Unaudited Quarterly Results </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R26.htm </HtmlFileName> |
| | | <LongName> 2122100 - Disclosure - Schedule I Summary of Investments </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleISummaryOfInvestments </Role> |
| | | <ShortName> Schedule I Summary of Investments </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R27.htm </HtmlFileName> |
| | | <LongName> 2123100 - Schedule - Condensed Finacial Information of Registrant </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/CondensedFinacialInformationOfRegistrant </Role> |
| | | <ShortName> Condensed Finacial Information of Registrant </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R28.htm </HtmlFileName> |
| | | <LongName> 2124100 - Schedule - Schedule III Supplementary Insurance Information </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleIiiSupplementaryInsuranceInformation </Role> |
| | | <ShortName> Schedule III Supplementary Insurance Information </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R29.htm </HtmlFileName> |
| | | <LongName> 2125100 - Schedule - Schedule IV Reinsurance </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleIvReinsurance </Role> |
| | | <ShortName> Schedule IV Reinsurance </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R30.htm </HtmlFileName> |
| | | <LongName> 2126100 - Schedule - Schedule V Valuation and Qualifying Accounts </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleVValuationAndQualifyingAccounts </Role> |
| | | <ShortName> Schedule V Valuation and Qualifying Accounts </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R31.htm </HtmlFileName> |
| | | <LongName> 2206201 - Disclosure - Signficant Accounting Policies (Policies) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SignficantAccountingPoliciesPolicies </Role> |
| | | <ShortName> Signficant Accounting Policies (Policies) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R32.htm </HtmlFileName> |
| | | <LongName> 2306302 - Disclosure - Significant Accounting Policies (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SignificantAccountingPoliciesTables </Role> |
| | | <ShortName> Significant Accounting Policies (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R33.htm </HtmlFileName> |
| | | <LongName> 2307301 - Disclosure - Fair Values of Financial Instruments (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/FairValuesOfFinancialInstrumentsTables </Role> |
| | | <ShortName> Fair Values of Financial Instruments (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R34.htm </HtmlFileName> |
| | | <LongName> 2308301 - Disclosure - Investments (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/InvestmentsTables </Role> |
| | | <ShortName> Investments (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R35.htm </HtmlFileName> |
| | | <LongName> 2309301 - Disclosure - Derivative Financial Instruments (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DerivativeFinancialInstrumentsTables </Role> |
| | | <ShortName> Derivative Financial Instruments (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R36.htm </HtmlFileName> |
| | | <LongName> 2310301 - Disclosure - Accumulated Other Comprehensive Income (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/AccumulatedOtherComprehensiveIncomeTables </Role> |
| | | <ShortName> Accumulated Other Comprehensive Income (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R37.htm </HtmlFileName> |
| | | <LongName> 2310301 - Disclosure - Liability for Unpaid Claims (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LiabilityForUnpaidClaimsTables </Role> |
| | | <ShortName> Liability for Unpaid Claims (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R38.htm </HtmlFileName> |
| | | <LongName> 2312301 - Disclosure - Income Tax (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/IncomeTaxTables </Role> |
| | | <ShortName> Income Tax (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R39.htm </HtmlFileName> |
| | | <LongName> 2313301 - Disclosure - Debt (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DebtTables </Role> |
| | | <ShortName> Debt (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R40.htm </HtmlFileName> |
| | | <LongName> 2314301 - Disclosure - Employee Benefit Plans (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansTables </Role> |
| | | <ShortName> Employee Benefit Plans (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R41.htm </HtmlFileName> |
| | | <LongName> 2315301 - Disclosure - Stockholders' Equity and Earnings Per Common Share Stockholders' Equity and Earnings Per Common Share (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockholdersEquityAndEarningsPerCommonShareStockholdersEquityAndEarningsPerCommonShareTables </Role> |
| | | <ShortName> Stockholders' Equity and Earnings Per Common Share Stockholders' Equity and Earnings Per Common Share (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R42.htm </HtmlFileName> |
| | | <LongName> 2316301 - Disclosure - Stock-Based Compensation (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockBasedCompensationTables </Role> |
| | | <ShortName> Stock-Based Compensation (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R43.htm </HtmlFileName> |
| | | <LongName> 2317301 - Disclosure - Reinsurance (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ReinsuranceTables </Role> |
| | | <ShortName> Reinsurance (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R44.htm </HtmlFileName> |
| | | <LongName> 2318301 - Disclosure - Segment Information (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SegmentInformationTables </Role> |
| | | <ShortName> Segment Information (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R45.htm </HtmlFileName> |
| | | <LongName> 2320302 - Disclosure - Statutory Financial Information (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StatutoryFinancialInformationTables </Role> |
| | | <ShortName> Statutory Financial Information (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R46.htm </HtmlFileName> |
| | | <LongName> 2321302 - Disclosure - Unaudited Quarterly Results (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/UnauditedQuarterlyResultsTables </Role> |
| | | <ShortName> Unaudited Quarterly Results (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R47.htm </HtmlFileName> |
| | | <LongName> 2322301 - Disclosure - Schedule I Summary of Investments (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleISummaryOfInvestmentsTables </Role> |
| | | <ShortName> Schedule I Summary of Investments (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R48.htm </HtmlFileName> |
| | | <LongName> 2323301 - Schedule - Condensed Financial Information of Registrant (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/CondensedFinancialInformationOfRegistrantTables </Role> |
| | | <ShortName> Condensed Financial Information of Registrant (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R49.htm </HtmlFileName> |
| | | <LongName> 2324301 - Schedule - Schedule III Supplmentary Insurance Information (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleIiiSupplmentaryInsuranceInformationTables </Role> |
| | | <ShortName> Schedule III Supplmentary Insurance Information (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R50.htm </HtmlFileName> |
| | | <LongName> 2325301 - Schedule - Schedule IV Reinsurance (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleIvReinsuranceTables </Role> |
| | | <ShortName> Schedule IV Reinsurance (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R51.htm </HtmlFileName> |
| | | <LongName> 2326301 - Schedule - Schedule V Valuation and Qualifying Accounts (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleVValuationAndQualifyingAccountsTables </Role> |
| | | <ShortName> Schedule V Valuation and Qualifying Accounts (Tables) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R52.htm </HtmlFileName> |
| | | <LongName> 2406403 - Disclosure - Significant Accounting Policies - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SignificantAccountingPoliciesAdditionalInformationDetail </Role> |
| | | <ShortName> Significant Accounting Policies - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R53.htm </HtmlFileName> |
| | | <LongName> 2407402 - Disclosure - Carrying Amount and Fair Value of Financial Instruments (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/CarryingAmountAndFairValueOfFinancialInstrumentsDetail </Role> |
| | | <ShortName> Carrying Amount and Fair Value of Financial Instruments (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R54.htm </HtmlFileName> |
| | | <LongName> 2407403 - Disclosure - Fair Value Measurements by Input Level (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/FairValueMeasurementsByInputLevelDetail </Role> |
| | | <ShortName> Fair Value Measurements by Input Level (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R55.htm </HtmlFileName> |
| | | <LongName> 2407404 - Disclosure - Transfers of Assets between Level 1 and Level 2 (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/TransfersOfAssetsBetweenLevel1AndLevel2Detail </Role> |
| | | <ShortName> Transfers of Assets between Level 1 and Level 2 (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R56.htm </HtmlFileName> |
| | | <LongName> 2407405 - Disclosure - Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs (Level 3) (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ChangesInAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsLevel3Detail </Role> |
| | | <ShortName> Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs (Level 3) (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R57.htm </HtmlFileName> |
| | | <LongName> 2407406 - Disclosure - Quantitative Information Regarding Significant Unobservable Inputs (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/QuantitativeInformationRegardingSignificantUnobservableInputsDetails </Role> |
| | | <ShortName> Quantitative Information Regarding Significant Unobservable Inputs (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R58.htm </HtmlFileName> |
| | | <LongName> 2407407 - Disclosure - Fair Value of Financial Instruments Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/FairValueOfFinancialInstrumentsAdditionalInformationDetail </Role> |
| | | <ShortName> Fair Value of Financial Instruments Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R59.htm </HtmlFileName> |
| | | <LongName> 2408402 - Disclosure - Amortized Cost and Fair Values of Securities by Security Type (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/AmortizedCostAndFairValuesOfSecuritiesBySecurityTypeDetail </Role> |
| | | <ShortName> Amortized Cost and Fair Values of Securities by Security Type (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R60.htm </HtmlFileName> |
| | | <LongName> 2408403 - Disclosure - Length of Time Fixed Maturity Securities had been in a Gross Unrealized Loss Position (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LengthOfTimeFixedMaturitySecuritiesHadBeenInGrossUnrealizedLossPositionDetail </Role> |
| | | <ShortName> Length of Time Fixed Maturity Securities had been in a Gross Unrealized Loss Position (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R61.htm </HtmlFileName> |
| | | <LongName> 2408404 - Disclosure - Distribution of the Maturity Dates for Fixed Maturity Securities (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DistributionOfMaturityDatesForFixedMaturitySecuritiesDetail </Role> |
| | | <ShortName> Distribution of the Maturity Dates for Fixed Maturity Securities (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R62.htm </HtmlFileName> |
| | | <LongName> 2408405 - Disclosure - Mortgage Loans by Property Type (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/MortgageLoansByPropertyTypeDetail </Role> |
| | | <ShortName> Mortgage Loans by Property Type (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R63.htm </HtmlFileName> |
| | | <LongName> 2408406 - Disclosure - Mortgage Loans by Geographic Region (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/MortgageLoansByGeographicRegionDetail </Role> |
| | | <ShortName> Mortgage Loans by Geographic Region (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R64.htm </HtmlFileName> |
| | | <LongName> 2408407 - Disclosure - Mortgage Loans, Sorted by Applicable Credit Quality Indicators, Internal rating (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/MortgageLoansSortedByApplicableCreditQualityIndicatorsInternalRatingDetail </Role> |
| | | <ShortName> Mortgage Loans, Sorted by Applicable Credit Quality Indicators, Internal rating (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R65.htm </HtmlFileName> |
| | | <LongName> 2408408 - Disclosure - Mortgage Loans, Sorted by Applicable Credit Quality Indicators, Loan to Value Ratio (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/MortgageLoansSortedByApplicableCreditQualityIndicatorsLoanToValueRatioDetail </Role> |
| | | <ShortName> Mortgage Loans, Sorted by Applicable Credit Quality Indicators, Loan to Value Ratio (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R66.htm </HtmlFileName> |
| | | <LongName> 2408409 - Disclosure - Activity in Allowance for Credit Losses (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ActivityInAllowanceForCreditLossesDetail </Role> |
| | | <ShortName> Activity in Allowance for Credit Losses (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R67.htm </HtmlFileName> |
| | | <LongName> 2408410 - Disclosure - Impaired Mortgage Loans (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ImpairedMortgageLoansDetail </Role> |
| | | <ShortName> Impaired Mortgage Loans (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R68.htm </HtmlFileName> |
| | | <LongName> 2408411 - Disclosure - Investments Mortgage Loan Restructuring (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/InvestmentsMortgageLoanRestructuringDetail </Role> |
| | | <ShortName> Investments Mortgage Loan Restructuring (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R69.htm </HtmlFileName> |
| | | <LongName> 2408412 - Disclosure - Investments Offsetting for Derivatives and Securities Lending Balances (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/InvestmentsOffsettingForDerivativesAndSecuritiesLendingBalancesDetails </Role> |
| | | <ShortName> Investments Offsetting for Derivatives and Securities Lending Balances (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R70.htm </HtmlFileName> |
| | | <LongName> 2408413 - Disclosure - Investments Investment Income (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/InvestmentsInvestmentIncomeDetail </Role> |
| | | <ShortName> Investments Investment Income (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R71.htm </HtmlFileName> |
| | | <LongName> 2408414 - Disclosure - Realized Investment Gains and Losses Reported in Consolidated Statements of Income (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/RealizedInvestmentGainsAndLossesReportedInConsolidatedStatementsOfIncomeDetail </Role> |
| | | <ShortName> Realized Investment Gains and Losses Reported in Consolidated Statements of Income (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R72.htm </HtmlFileName> |
| | | <LongName> 2408415 - Disclosure - Investments - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/InvestmentsAdditionalInformationDetail </Role> |
| | | <ShortName> Investments - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R73.htm </HtmlFileName> |
| | | <LongName> 2409402 - Disclosure - Notional Amounts for Each Category of Derivative Activity (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/NotionalAmountsForEachCategoryOfDerivativeActivityDetail </Role> |
| | | <ShortName> Notional Amounts for Each Category of Derivative Activity (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R74.htm </HtmlFileName> |
| | | <LongName> 2409403 - Disclosure - Location and Fair Values of Derivative Financial Instruments (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LocationAndFairValuesOfDerivativeFinancialInstrumentsDetail </Role> |
| | | <ShortName> Location and Fair Values of Derivative Financial Instruments (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R75.htm </HtmlFileName> |
| | | <LongName> 2409404 - Disclosure - Location of Gains and Losses on Derivative Financial Instruments Designated as Cash Flow Hedging Instruments (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LocationOfGainsAndLossesOnDerivativeFinancialInstrumentsDesignatedAsCashFlowHedgingInstrumentsDetail </Role> |
| | | <ShortName> Location of Gains and Losses on Derivative Financial Instruments Designated as Cash Flow Hedging Instruments (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R76.htm </HtmlFileName> |
| | | <LongName> 2409405 - Disclosure - Location of and Gain (Loss) on Derivative Financial Instruments Not Designated as Hedging Instruments (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LocationOfAndGainLossOnDerivativeFinancialInstrumentsNotDesignatedAsHedgingInstrumentsDetail </Role> |
| | | <ShortName> Location of and Gain (Loss) on Derivative Financial Instruments Not Designated as Hedging Instruments (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R77.htm </HtmlFileName> |
| | | <LongName> 2409406 - Disclosure - Derivative Financial Instruments - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DerivativeFinancialInstrumentsAdditionalInformationDetail </Role> |
| | | <ShortName> Derivative Financial Instruments - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R78.htm </HtmlFileName> |
| | | <LongName> 2410402 - Disclosure - Liability for Unpaid Claims Recon (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LiabilityForUnpaidClaimsReconDetail </Role> |
| | | <ShortName> Liability for Unpaid Claims Recon (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R79.htm </HtmlFileName> |
| | | <LongName> 2410402 - Disclosure - Schedule of Other Comprehensive Income (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleOfOtherComprehensiveIncomeDetails </Role> |
| | | <ShortName> Schedule of Other Comprehensive Income (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R80.htm </HtmlFileName> |
| | | <LongName> 2410403 - Disclosure - Reconciliation of Policy and Contract Benefits and Reserves for Future Policy and Contract Benefits (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ReconciliationOfPolicyAndContractBenefitsAndReservesForFuturePolicyAndContractBenefitsDetail </Role> |
| | | <ShortName> Reconciliation of Policy and Contract Benefits and Reserves for Future Policy and Contract Benefits (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R81.htm </HtmlFileName> |
| | | <LongName> 2410403 - Disclosure - Schedule of Net Unrealized Gain on Securities (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleOfNetUnrealizedGainOnSecuritiesDetails </Role> |
| | | <ShortName> Schedule of Net Unrealized Gain on Securities (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R82.htm </HtmlFileName> |
| | | <LongName> 2410404 - Disclosure - Liability for Unpaid Claims - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/LiabilityForUnpaidClaimsAdditionalInformationDetail </Role> |
| | | <ShortName> Liability for Unpaid Claims - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R83.htm </HtmlFileName> |
| | | <LongName> 2410404 - Disclosure - Schedule of Reclassifications from Accumulated Other Comprehensive Income to Income (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleOfReclassificationsFromAccumulatedOtherComprehensiveIncomeToIncomeDetails </Role> |
| | | <ShortName> Schedule of Reclassifications from Accumulated Other Comprehensive Income to Income (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R84.htm </HtmlFileName> |
| | | <LongName> 2412402 - Disclosure - Income Tax (Benefit)(Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/IncomeTaxBenefitdetail </Role> |
| | | <ShortName> Income Tax (Benefit)(Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R85.htm </HtmlFileName> |
| | | <LongName> 2412403 - Disclosure - Reconciliation of income tax computed at US Federal tax rates (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ReconciliationOfIncomeTaxComputedAtUsFederalTaxRatesDetail </Role> |
| | | <ShortName> Reconciliation of income tax computed at US Federal tax rates (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R86.htm </HtmlFileName> |
| | | <LongName> 2412404 - Disclosure - Schedule of deferred income tax assets and liabilities (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleOfDeferredIncomeTaxAssetsAndLiabilitiesDetail </Role> |
| | | <ShortName> Schedule of deferred income tax assets and liabilities (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R87.htm </HtmlFileName> |
| | | <LongName> 2412405 - Disclosure - Schedule of Income subject to domestic and foreign taxation (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleOfIncomeSubjectToDomesticAndForeignTaxationDetail </Role> |
| | | <ShortName> Schedule of Income subject to domestic and foreign taxation (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R88.htm </HtmlFileName> |
| | | <LongName> 2412406 - Disclosure - Unrecognized tax benefits (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/UnrecognizedTaxBenefitsDetail </Role> |
| | | <ShortName> Unrecognized tax benefits (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R89.htm </HtmlFileName> |
| | | <LongName> 2412407 - Disclosure - Income Tax Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/IncomeTaxAdditionalInformationDetail </Role> |
| | | <ShortName> Income Tax Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R90.htm </HtmlFileName> |
| | | <LongName> 2413402 - Disclosure - Debt Schedule (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DebtScheduleDetail </Role> |
| | | <ShortName> Debt Schedule (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R91.htm </HtmlFileName> |
| | | <LongName> 2413403 - Disclosure - Debt - Additional Information Domain (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/DebtAdditionalInformationDomainDetail </Role> |
| | | <ShortName> Debt - Additional Information Domain (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R92.htm </HtmlFileName> |
| | | <LongName> 2414402 - Disclosure - Employee Benefit Plans Change in Projected Benefit Obligation Amount (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansChangeInProjectedBenefitObligationAmountDetails </Role> |
| | | <ShortName> Employee Benefit Plans Change in Projected Benefit Obligation Amount (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R93.htm </HtmlFileName> |
| | | <LongName> 2414403 - Disclosure - Employee Benefit Plans Net Periodic Benefit Cost (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansNetPeriodicBenefitCostDetail </Role> |
| | | <ShortName> Employee Benefit Plans Net Periodic Benefit Cost (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R94.htm </HtmlFileName> |
| | | <LongName> 2414404 - Disclosure - Employee Benefit Plans Amounts Recognized in Balance Sheet (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansAmountsRecognizedInBalanceSheetDetails </Role> |
| | | <ShortName> Employee Benefit Plans Amounts Recognized in Balance Sheet (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R95.htm </HtmlFileName> |
| | | <LongName> 2414405 - Disclosure - Employee Benefit Plans Amounts Recognized in Other Comprehensive Income (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansAmountsRecognizedInOtherComprehensiveIncomeDetails </Role> |
| | | <ShortName> Employee Benefit Plans Amounts Recognized in Other Comprehensive Income (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R96.htm </HtmlFileName> |
| | | <LongName> 2414406 - Disclosure - Employee Benefit Plans US Pension Assets, Fair Value Inputs (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansUsPensionAssetsFairValueInputsDetails </Role> |
| | | <ShortName> Employee Benefit Plans US Pension Assets, Fair Value Inputs (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R97.htm </HtmlFileName> |
| | | <LongName> 2414407 - Disclosure - Employee Benefit Plans US Changes in Assets measured at fair value using significant unobservable inputs (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansUsChangesInAssetsMeasuredAtFairValueUsingSignificantUnobservableInputsDetails </Role> |
| | | <ShortName> Employee Benefit Plans US Changes in Assets measured at fair value using significant unobservable inputs (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R98.htm </HtmlFileName> |
| | | <LongName> 2414408 - Disclosure - Employee Benefit Plans UK Pension Assets, Fair Value Measurement by Input Level (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansUkPensionAssetsFairValueMeasurementByInputLevelDetails </Role> |
| | | <ShortName> Employee Benefit Plans UK Pension Assets, Fair Value Measurement by Input Level (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R99.htm </HtmlFileName> |
| | | <LongName> 2414409 - Disclosure - Employee Benefit Plans OPEB Plan Assets, Fair Value Measurements by Input Level (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansOpebPlanAssetsFairValueMeasurementsByInputLevelDetails </Role> |
| | | <ShortName> Employee Benefit Plans OPEB Plan Assets, Fair Value Measurements by Input Level (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R100.htm </HtmlFileName> |
| | | <LongName> 2414410 - Disclosure - Employee Benefit Plans OPEB Changes in Assets Measured at Fair Value Using Signficant Unobservable Inputs (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansOpebChangesInAssetsMeasuredAtFairValueUsingSignficantUnobservableInputsDetails </Role> |
| | | <ShortName> Employee Benefit Plans OPEB Changes in Assets Measured at Fair Value Using Signficant Unobservable Inputs (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R101.htm </HtmlFileName> |
| | | <LongName> 2414411 - Disclosure - Employee Benefit Plans Measurement Assumptions (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansMeasurementAssumptionsDetails </Role> |
| | | <ShortName> Employee Benefit Plans Measurement Assumptions (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R102.htm </HtmlFileName> |
| | | <LongName> 2414412 - Disclosure - Employee Benefit Plans Expected Benefit Payments (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansExpectedBenefitPaymentsDetails </Role> |
| | | <ShortName> Employee Benefit Plans Expected Benefit Payments (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R103.htm </HtmlFileName> |
| | | <LongName> 2414413 - Disclosure - Employee Benefit Plans - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/EmployeeBenefitPlansAdditionalInformationDetail </Role> |
| | | <ShortName> Employee Benefit Plans - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R104.htm </HtmlFileName> |
| | | <LongName> 2415402 - Disclosure - Net Income Per Common Share (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/NetIncomePerCommonShareDetail </Role> |
| | | <ShortName> Net Income Per Common Share (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R105.htm </HtmlFileName> |
| | | <LongName> 2415403 - Disclosure - Stockholders' Equity and Earnings Per Common Share Authorized share repurchase programs (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockholdersEquityAndEarningsPerCommonShareAuthorizedShareRepurchaseProgramsDetails </Role> |
| | | <ShortName> Stockholders' Equity and Earnings Per Common Share Authorized share repurchase programs (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R106.htm </HtmlFileName> |
| | | <LongName> 2415404 - Disclosure - Stockholders' Equity and Earnings Per Common Share Share Repurchases (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockholdersEquityAndEarningsPerCommonShareShareRepurchasesDetails </Role> |
| | | <ShortName> Stockholders' Equity and Earnings Per Common Share Share Repurchases (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R107.htm </HtmlFileName> |
| | | <LongName> 2415405 - Disclosure - Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockholdersEquityAndEarningsPerCommonShareAdditionalInformationDetail </Role> |
| | | <ShortName> Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R108.htm </HtmlFileName> |
| | | <LongName> 2416402 - Disclosure - Stock-Based Compensation - Nonvested Stock Awards Classified in Equity (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockBasedCompensationNonvestedStockAwardsClassifiedInEquityDetail </Role> |
| | | <ShortName> Stock-Based Compensation - Nonvested Stock Awards Classified in Equity (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R109.htm </HtmlFileName> |
| | | <LongName> 2416403 - Disclosure - Stock-Based Compensation Stock-Based Compensation - Cash Settled Awards Classified as Liability (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockBasedCompensationStockBasedCompensationCashSettledAwardsClassifiedAsLiabilityDetails </Role> |
| | | <ShortName> Stock-Based Compensation Stock-Based Compensation - Cash Settled Awards Classified as Liability (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R110.htm </HtmlFileName> |
| | | <LongName> 2416404 - Disclosure - Stock-Based Compensation Expense (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockBasedCompensationExpenseDetail </Role> |
| | | <ShortName> Stock-Based Compensation Expense (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R111.htm </HtmlFileName> |
| | | <LongName> 2416405 - Disclosure - Stock-Based Compensation - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockBasedCompensationAdditionalInformationDetail </Role> |
| | | <ShortName> Stock-Based Compensation - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R112.htm </HtmlFileName> |
| | | <LongName> 2416406 - Disclosure - Stock option activity (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StockOptionActivityDetail </Role> |
| | | <ShortName> Stock option activity (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R113.htm </HtmlFileName> |
| | | <LongName> 2417402 - Disclosure - Reinsurance - Premium Income Data (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ReinsurancePremiumIncomeDataDetail </Role> |
| | | <ShortName> Reinsurance - Premium Income Data (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R114.htm </HtmlFileName> |
| | | <LongName> 2417403 - Disclosure - Reinsurance - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ReinsuranceAdditionalInformationDetail </Role> |
| | | <ShortName> Reinsurance - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R115.htm </HtmlFileName> |
| | | <LongName> 2418402 - Disclosure - Reconciliation of Total Operating Revenue and Operating Income by Segment to Revenue and Net Income (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ReconciliationOfTotalOperatingRevenueAndOperatingIncomeBySegmentToRevenueAndNetIncomeDetail </Role> |
| | | <ShortName> Reconciliation of Total Operating Revenue and Operating Income by Segment to Revenue and Net Income (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R116.htm </HtmlFileName> |
| | | <LongName> 2418403 - Disclosure - Premium Income by Major Line of Business within Each Segment (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/PremiumIncomeByMajorLineOfBusinessWithinEachSegmentDetail </Role> |
| | | <ShortName> Premium Income by Major Line of Business within Each Segment (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R117.htm </HtmlFileName> |
| | | <LongName> 2418404 - Disclosure - Selected Operating Statement Data by Segment (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SelectedOperatingStatementDataBySegmentDetail </Role> |
| | | <ShortName> Selected Operating Statement Data by Segment (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R118.htm </HtmlFileName> |
| | | <LongName> 2418405 - Disclosure - Segment Information Deferred Acquisition Costs by Segment (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SegmentInformationDeferredAcquisitionCostsBySegmentDetails </Role> |
| | | <ShortName> Segment Information Deferred Acquisition Costs by Segment (Details) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R119.htm </HtmlFileName> |
| | | <LongName> 2418406 - Disclosure - Assets by Segment (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/AssetsBySegmentDetail </Role> |
| | | <ShortName> Assets by Segment (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R120.htm </HtmlFileName> |
| | | <LongName> 2418407 - Disclosure - Segment Information Segments - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/SegmentInformationSegmentsAdditionalInformationDetail </Role> |
| | | <ShortName> Segment Information Segments - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R121.htm </HtmlFileName> |
| | | <LongName> 2419401 - Disclosure - Commitments and Contingent Liabilities - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/CommitmentsAndContingentLiabilitiesAdditionalInformationDetail </Role> |
| | | <ShortName> Commitments and Contingent Liabilities - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R122.htm </HtmlFileName> |
| | | <LongName> 2420400 - Disclosure - Combined Statutory Capital and Surplus (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/CombinedStatutoryCapitalAndSurplusDetail </Role> |
| | | <ShortName> Combined Statutory Capital and Surplus (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R123.htm </HtmlFileName> |
| | | <LongName> 2420403 - Disclosure - Statutory Financial Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StatutoryFinancialInformationDetail </Role> |
| | | <ShortName> Statutory Financial Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R124.htm </HtmlFileName> |
| | | <LongName> 2420404 - Disclosure - Statutory Financial Information - Additional Details (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/StatutoryFinancialInformationAdditionalDetailsDetail </Role> |
| | | <ShortName> Statutory Financial Information - Additional Details (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R125.htm </HtmlFileName> |
| | | <LongName> 2421400 - Disclosure - Schedule of Unaudited Quarterly Results (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleOfUnauditedQuarterlyResultsDetail </Role> |
| | | <ShortName> Schedule of Unaudited Quarterly Results (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R126.htm </HtmlFileName> |
| | | <LongName> 2421403 - Disclosure - Unaudited Quarterly Results - Additional Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/UnauditedQuarterlyResultsAdditionalInformationDetail </Role> |
| | | <ShortName> Unaudited Quarterly Results - Additional Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R127.htm </HtmlFileName> |
| | | <LongName> 2422402 - Disclosure - Schedule I Summary of Investments (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleISummaryOfInvestmentsDetail </Role> |
| | | <ShortName> Schedule I Summary of Investments (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R128.htm </HtmlFileName> |
| | | <LongName> 2423402 - Schedule - Parent Company Balance Sheet (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ParentCompanyBalanceSheetDetail </Role> |
| | | <ShortName> Parent Company Balance Sheet (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R129.htm </HtmlFileName> |
| | | <LongName> 2423403 - Schedule - Parent Company Balance Sheet (Parenthetical) (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ParentCompanyBalanceSheetParentheticalDetail </Role> |
| | | <ShortName> Parent Company Balance Sheet (Parenthetical) (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R130.htm </HtmlFileName> |
| | | <LongName> 2423404 - Schedule - Parent Company Statement of Income (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ParentCompanyStatementOfIncomeDetail </Role> |
| | | <ShortName> Parent Company Statement of Income (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R131.htm </HtmlFileName> |
| | | <LongName> 2423405 - Schedule - Parent Company Cash Flow Statement (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ParentCompanyCashFlowStatementDetail </Role> |
| | | <ShortName> Parent Company Cash Flow Statement (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R132.htm </HtmlFileName> |
| | | <LongName> 2423406 - Schedule - Parent Company Debt Schedule (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ParentCompanyDebtScheduleDetail </Role> |
| | | <ShortName> Parent Company Debt Schedule (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R133.htm </HtmlFileName> |
| | | <LongName> 2423407 - Schedule - Parent Company Notes - Additional Details (Detail) </LongName> |
| | | <ReportType> Notes </ReportType> |
| | | <Role> http://www.unum.com/role/ParentCompanyNotesAdditionalDetailsDetail </Role> |
| | | <ShortName> Parent Company Notes - Additional Details (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R134.htm </HtmlFileName> |
| | | <LongName> 2424402 - Schedule - Schedule III Supplementary Insurance Information (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleIiiSupplementaryInsuranceInformationDetail </Role> |
| | | <ShortName> Schedule III Supplementary Insurance Information (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R135.htm </HtmlFileName> |
| | | <LongName> 2425402 - Schedule - Schedule IV Reinsurance (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleIvReinsuranceDetail </Role> |
| | | <ShortName> Schedule IV Reinsurance (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R136.htm </HtmlFileName> |
| | | <LongName> 2426402 - Schedule - Schedule V Valuation and Qualifying Accounts (Detail) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.unum.com/role/ScheduleVValuationAndQualifyingAccountsDetail </Role> |
| | | <ShortName> Schedule V Valuation and Qualifying Accounts (Detail) </ShortName> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <LongName> All Reports </LongName> |
| | | <ReportType> Book </ReportType> |
| | | <ShortName> All Reports </ShortName> |
| | | </Report> |
| | </MyReports> |
| <Logs> |
| | <Log type="Info"> Element unm_NumberofSharesforEachFullValueAward had a mix of decimals attribute values: 1 2. </Log> |
| | <Log type="Info"> Element us-gaap_EffectiveIncomeTaxRateContinuingOperations had a mix of decimals attribute values: 0 3. </Log> |
| | <Log type="Info"> Element us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes had a mix of decimals attribute values: 0 3. </Log> |
| | <Log type="Info"> Element us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized had a mix of decimals attribute values: -6 0. </Log> |
| | <Log type="Info"> 'Monetary' elements on report '2408415 - Disclosure - Investments - Additional Information (Detail)' had a mix of different decimal attribute values. </Log> |
| | <Log type="Info"> 'Monetary' elements on report '2412407 - Disclosure - Income Tax Additional Information (Detail)' had a mix of different decimal attribute values. </Log> |
| | <Log type="Info"> 'Monetary' elements on report '2414413 - Disclosure - Employee Benefit Plans - Additional Information (Detail)' had a mix of different decimal attribute values. </Log> |
| | <Log type="Info"> 'Shares' elements on report '2415405 - Disclosure - Stockholders' Equity and Earnings Per Common Share - Additional Information (Detail)' had a mix of different decimal attribute values. </Log> |
| | <Log type="Info"> 'Shares' elements on report '2416405 - Disclosure - Stock-Based Compensation - Additional Information (Detail)' had a mix of different decimal attribute values. </Log> |
| | <Log type="Info"> Process Flow-Through: 1001000 - Statement - CONSOLIDATED BALANCE SHEETS </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column 'Dec. 31, 2011' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column 'Dec. 31, 2010' </Log> |
| | <Log type="Info"> Process Flow-Through: 1001501 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) </Log> |
| | <Log type="Info"> Process Flow-Through: 1002000 - Statement - CONSOLIDATED STATEMENTS OF INCOME </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Dec. 31, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Sep. 30, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Jun. 30, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Mar. 31, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Dec. 31, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Sep. 30, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Jun. 30, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Mar. 31, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: 1003000 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Dec. 31, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Sep. 30, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Jun. 30, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Mar. 31, 2013' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Dec. 31, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Sep. 30, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Jun. 30, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: Removing column '3 Months Ended Mar. 31, 2012' </Log> |
| | <Log type="Info"> Process Flow-Through: 1003500 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) </Log> |
| | <Log type="Info"> Process Flow-Through: 1004500 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) </Log> |
| | <Log type="Info"> Process Flow-Through: 1005000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS </Log> |
| | </Logs> |
| <InputFiles> |
| | <File> unm-20131231.xml </File> |
| | <File> unm-20131231.xsd </File> |
| | <File> unm-20131231_cal.xml </File> |
| | <File> unm-20131231_def.xml </File> |
| | <File> unm-20131231_lab.xml </File> |
| | <File> unm-20131231_pre.xml </File> |
| | </InputFiles> |
| <SupplementalFiles/> |
| <BaseTaxonomies/> |
| <HasPresentationLinkbase> true </HasPresentationLinkbase> |
| <HasCalculationLinkbase> true </HasCalculationLinkbase> |
| </FilingSummary> |