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Location of Gains and Losses on Derivative Financial Instruments Designated as Cash Flow Hedging Instruments [Abstract] Compensation Expense Labor and Related Expense Reconciliation of Total Revenue and Income Before Income Tax to Adjusted Operating Revenue and Adjusted Operating Income Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Security Exchange Name Security Exchange Name Available For Sale Securities Debt Maturities After Ten Years Unrealized Gain Position Gross Gain Available For Sale Securities Debt Maturities After Ten Years Unrealized Gain Position Gross Gain Available For Sale Securities Debt Maturities After Ten Years Unrealized Gain Position Gross Gain Total Financial Instrument Assets Not Carried at Fair Value Financial Instruments, Financial Assets Fair Value Disclosure, Carrying Value Financial Instruments, Financial Assets Fair Value Disclosure, Carrying Value Proceeds from Issuance of Long-term Debt Proceeds from Issuance of Long-term Debt Credit Default Swaps Credit Risk Contract Credit Risk Contract [Member] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Gross Losses on Sales Debt Securities, Available-for-sale, Realized Loss Liabilities Offsetting Securities Borrowed in Balance Sheet Securities Borrowed, Liability Mortgage Loan Property Type Real Estate, Type of Property [Axis] Assets Assets, Fair Value Disclosure Assets [Abstract] Accounting Policies [Abstract] Accounting Policies [Abstract] Proceeds from Sales and Maturities of Other Investments Proceeds from Sale and Maturity of Other Investments Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3 Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Allowance for Credit Losses, Unfunded Mortgage Loan Commitments Accounts and Financing Receivable, Allowance for Credit Loss Fair Value, Balance Sheet Grouping, Financial Statement Captions Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] All Other Corporate Bonds - 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Redemptions are allowed quarterly after 2 year lock with 90 days notice. 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For interest sensitive products, benefits are the amounts paid and expected to be paid on insured claims in excess of the policyholders' policy fund balances. 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Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table] Individual Disability Individual Disability Insurance [Member] Individual Disability Insurance [Member] Stockholders' Equity and Earnings Per Common Share [Abstract] Stockholders' Equity and Earnings Per Common Share [Abstract] Stockholders' Equity and Earnings Per Common Share [Abstract] Less Reinsurance Recoverable Plus Reinsurance Recoverable Reinsurance Recoverables, Incurred but Not Reported Claims Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Group Long-term Disability Group Long term Disability [Member] Group Long Term Disability [Member] Credit Losses Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease) and Other Than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease) and Other Than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Outstanding Restricted Stock Unit Grant Prices Upper Limit Outstanding Restricted Stock Unit Grant Prices Upper Limit Outstanding Restricted Stock Unit Grant Prices Upper Limit Credit Exposure on Derivatives Fair Value, Concentration of Risk, Derivative Instruments, Assets Originated in Current Fiscal Year Originated in Current Fiscal Year [Member] Originated in Current Fiscal Year Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment Net Purchases of Property and Equipment Payments to Acquire Property, Plant, and Equipment Consolidation Items Consolidation Items [Domain] Restatement Adjustment Revision of Prior Period, Adjustment [Member] Debt Securities, Available-for-sale, Allowance for credit losses for Fixed Maturity Securities Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance Debt Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance Debt Securities, Available-for-sale, Allowance for Credit Loss Amortization of Deferred Acquisition Costs Deferred Policy Acquisition Costs, Amortization Expense Income Before Income Tax Income Before Income Tax Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Hedging Designation Hedging Designation [Axis] Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract] Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Domain] Impairment Loss on ROU Asset Impairment Loss on ROU Asset Operating Lease, Impairment Loss Equity Securities Equity Securities, FV-NI Legal Entity Entity [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Derivative, Cost of Hedge Derivative, Cost of Hedge Financing Receivable, Modifications, Number of Contracts Financing Receivable, Modifications, Number of Contracts Gains and Losses on Derivatives Not Designated as Hedging Instruments Derivatives Not Designated as Hedging Instruments [Table Text Block] Long-term Care Long term Care [Member] Long Term Care [Member] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3 Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Fixed Maturity Securities - at fair value (amortized cost of $41,239.4; $41,079.3; allowance for credit losses of $12.5; $—) Fixed Maturity Securities Debt Securities, Available-for-sale, Total Debt Securities, Available-for-sale Schedule of Net Unrealized Gain on Securities Schedule of Net Unrealized Gain on Securities [Table] Schedule of Net Unrealized Gain on Securities [Table] Debt Instrument, Repurchased Face Amount Debt Instrument, Repurchased Face Amount Change in Net Gain on Hedges, Tax Benefit Other Comprehensive Income (Loss), Net Gain on Hedges, Adjustment, Tax Amount of tax expense (benefit), after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of hedges. 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Cover [Abstract] Measurement Input Type Measurement Input Type [Axis] Redemption Term Redemption Term [Axis] Disclosure of information about partnership equity securities with redemption features. [Axis] Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance, Tax Benefit Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance, Tax Expense Tax effect from the unrealized adjustment to deferred acquisition costs and reserves for future policy and contract benefits for unrealized loss on securities during the period net of the effects of contracts assumed and ceded Other Comprehensive Income (Loss) Before Reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Derivative, Loss on Derivative Derivative, Loss on Derivative Disclosure Mortgage Loans by Property Type [Abstract] Disclosure Mortgage Loans by Property Type [Abstract] Disclosure - Mortgage Loans by Property Type [Abstract] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk Derivative 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Revenues [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Stockholders' Equity Disclosure Stockholders' Equity Note Disclosure [Text Block] Recoveries Financing Receivable, Allowance for Credit Loss, Recovery Proceeds from Maturities of Fixed Maturity Securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Reconciliation of Revenue from Segments to Consolidated Reconciliation of Revenue from Segments to Consolidated [Table] Derivative Derivative [Table] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Debt Securities, Available-for-sale, Unrealized Loss Position Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items] Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10, Net Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity 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[Member] Office Office Building [Member] Net Realized Investment Gain (Loss) Gain (Loss) on Investments [Member] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Offsetting Derivative Liabilities Offsetting Derivative Liabilities [Abstract] Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Cash and Bank Deposits Cash Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Document Transition Report Document Transition Report Derivative Asset, Fair Value, Gross Asset Asset Derivatives Fair Value Derivative Asset, Fair Value, Gross Asset Change in Components of Net Unrealized Gain on Securities Change in 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[Abstract] Disclosure - Notional Amounts for Each Category of Derivative Activity [Abstract] Pacific Pacific [Member] Pacific [Member] Off Balance Sheet Amount Off Balance Sheet Amount [Member] Off Balance Sheet Amount [Member] Net Unrealized Gain on Securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Credit Default Swaps Credit Default Swaps Credit Default Swap [Member] Hedged Asset, Fair Value Hedge Hedged Asset, Fair Value Hedge Derivative Instrument by Balance Sheet Location Derivative Instrument by Balance Sheet Location Balance Sheet Location [Axis] Apartment Apartment Building [Member] Commercial Real Estate Commercial Real Estate [Member] Distribution by External Credit Rating for Fixed Maturity Securities Available for Sale Debt Securities by External Credit Rating [Table Text Block] Available for Sale Debt Securities by External Credit Rating [Table Text Block] Amortization of Affordable Housing Tax Credit Investments Amortization Method Qualified Affordable Housing Project Investments, Amortization Retirement Benefits [Abstract] Retirement Benefits [Abstract] Deferred Acquisition Costs Deferred Acquisition Costs [Member] Deferred Acquisition Costs [Member] Fair Value Inputs Other Than Level 1 Fair Value Inputs Other Than Level 1 [Member] Fair Value Inputs Other Than Level 1 [Member] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases Total Financial Instrument Liabilities Not Carried at Fair Value Total Financial Instrument Liabilities Not Carried at Fair Value Total Financial Instrument Liabilities Not Carried at Fair Value Total Total [Member] Total Cash Flows from Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Component of Net Unrealized Gain on Securities Component of Net Unrealized Gain on Securities [Axis] Component of Net Unrealized Gain on Securities [Axis] Federal Home Loan Bank, Collateral Posted to FHLB Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged Commercial Mortgage Loans Collateralized Mortgage Backed Securities [Member] Derivative Liabilities Offsetting Derivative Assets in Balance Sheet Derivative Asset, Fair Value, Gross Liability Interest and Debt Expense Interest Expense [Member] Notes 5.625 Due 2020 Notes 5.625 Due 2020 [Member] Notes 5.625 Due 2020 Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Total Liabilities and Stockholders' Equity Liabilities and Equity Debt Securities, Available-for-sale, Credit losses on securities for which credit losses were not previously recorded Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Loss), Net of Tax Income Tax Disclosure Income Tax Disclosure [Text Block] Debt and Other Disclosures [Abstract] Debt and Other Disclosures Hedging Relationship Hedging Relationship [Axis] Antidilutive Securities Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Credit Exposure Credit Exposure [Domain] [Domain] for Credit Exposure [Axis] Current Current Income Tax Expense (Benefit) Other, Net Other Noncash Income (Expense) Equity Component Equity Component [Domain] Change in Net Unrealized Gain on Securities Before Adjustment (net of tax expense of $126.6; $209.5; $344.0; $815.6) Change in Net Unrealized Gain on Securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Outstanding Restricted Stock Unit Grant Prices Lower Limit Outstanding Restricted Stock Unit Grant Prices Lower Limit Outstanding Restricted Stock Unit Grant Prices Lower Limit Fair Value, Investments, Entities that Calculate Net Asset Value Per Share Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block] Property and Equipment Property, Plant and Equipment, Net Entity Tax Identification Number Entity Tax Identification Number Net Income Net Income Net Income (Loss) Attributable to Parent Current Period Provisions Financing Receivable, Credit Loss, Expense (Reversal) Heirarchy Level Combination Heirarchy Level Combination [Axis] Heirarchy Level Combination [Axis] Current Fiscal Year End Date Current Fiscal Year End Date Retirement Plan Sponsor Location Retirement Plan Sponsor Location [Domain] Accounting Updates Outstanding Description of New Accounting Pronouncements Not yet Adopted [Text Block] Private Equity Funds Private Equity Funds [Member] Originated Five or More Years before Last Fiscal Year Originated Five or More Years before Last Fiscal Year [Member] Originated Five or More Years before Last Fiscal Year Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) [Line Items] Loan To Value Ratio Above 65 To 75 Percent Loan To Value Ratio Above 65 To 75 Percent [Member] Loan To Value Ratio Above 65 To 75 Percent [Member] Policy Loans, Fair Value Disclosure Loans Receivable, Fair Value Disclosure Offsetting Assets and Liabilities Offsetting Liabilities [Table] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] Financing Receivable, Credit Quality Indicator, Mortgage Loans Financing Receivable, Credit Quality Indicator [Table] Credit Derivatives Contract Type Credit Derivatives Contract Type [Axis] Originated Two Years before Last Fiscal Year Originated Two Years before Last Fiscal Year [Member] Originated Two Years before Last Fiscal Year Financing Receivable, Originated in Current Fiscal Year Financing Receivable, Year One, Originated, Current Fiscal Year Defined Benefit Plan, Benefit Obligation, Benefits Paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Periodic Principal Payments Debt Instrument, Periodic Payment, Principal Dividends to Stockholders (per common share: $0.285; $0.285; $0.855; $0.805) Dividends, Cash Debt Securities, Available-for-sale, Allowance for Credit Loss Debt Securities, Available-for-sale, Allowance for Credit Loss [Table] Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Number of Fixed Maturity Securities in an Unrealized Loss Position Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table] Fair Value Maturity Distribution [Abstract] Fair Value Maturity Distribution [Abstract] Fair Value Maturity Distribution [Abstract] Ceded Policy Loans Policy Loans Ceded to Reinsurers Loans ceded to reinsurers. These loans use insurance policy funds such as cash surrender values as collateral. Available For Sale Securities Debt Maturities After Ten Years Unrealized Loss Position Gross Loss Available For Sale Securities Debt Maturities After Ten Years Unrealized Loss Position Gross Loss Available For Sale Securities Debt Maturities After Ten Years Unrealized Loss Position Gross Loss Change in Foreign Currency Translation Adjustment, Tax Expense (Benefit) Change in Foreign Currency Translation Adjustment, Tax Expense (Benefit) Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Hedging Relationship Hedging Relationship [Domain] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Private Equity Fund Type Private Equity Fund Type [Axis] Private Equity Fund Type [Axis] Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Gain Position Gross Gain Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Gain Position Gross Gain Available For Sale Securities Debt Maturities After One Through Five Years Unrealized Gain Position Gross Gain Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Loss Position Gross Loss Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Loss Position Gross Loss Available For Sale Securities Debt Maturities Without Single Maturity Date Unrealized Loss Position Gross Loss Weighted Average Common Shares - Basic Weighted Average Number of Shares Outstanding, Basic Commissions Insurance Commissions Cash Flow Hedging Cash Flow Hedging [Member]