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Value for Commercial Mortgage and Other Loans by Property Type Schedule of Participating Mortgage Loans [Table Text Block] Investments Classified by Contractual Maturity Date [Table] Investments Classified by Contractual Maturity Date [Table] Investments Classified by Contractual Maturity Date [Table] Total investments and cash Total investments and cash Investments and Cash Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Investments in Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Derivative asset, fair value, gross asset including not subject to master netting arrangement Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement Financing Receivable, Troubled Debt Restructuring Financing Receivable, Troubled Debt Restructuring .844% senior notes due April 2033 Senior Notes Point Eight Four Four Percent Due April Twenty Thirty Three [Member] Senior Notes Point Eight Four Four Percent Due 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One Two Five percent Due March Twenty Twenty Six Level 3 Fair Value, Inputs, Level 3 [Member] Gross amount of recognized assets Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Gross Including Not Subject to Master Netting Arrangement SHARE-BASED COMPENSATION Share-Based Payment Arrangement [Text Block] Fixed maturity securities Fixed maturity securities Fixed Maturities [Member] Held to maturity, fixed maturity securities, fair value Fair Value Fair Value Debt Securities, Held-to-Maturity, Fair Value Percentage that the lending policy requires that the fair value of the unrestricted cash received as collateral be of the fair value of the loaned securities Collateral Requirements Minimum Percentage Unrestricted Cash Collateral to Fair Value of the Loaned Securities Percentage that the lending policy requires that the fair value of the unrestricted cash received as collateral be of the fair value of the loaned securities in securities lending transactions. Debt instrument, term Debt Instrument, Term 50.0 billion yen line of credit (Tranche 2) Fifty billion yen line of credit (Tranche 2) [Member] Fifty billion yen line of credit (Tranche 2) Gains (losses) recognized for hedged items Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Schedule of Common Stock Outstanding Roll Forward Schedule of Common Stock Outstanding Roll Forward [Table Text Block] Accumulated Other Comprehensive Income [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] Level 2 Fair Value, Inputs, Level 2 [Member] Current Fiscal Year End Date Current Fiscal Year End Date Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Loss contingency, insurance-related assessment, discounted amount of premium tax offset Loss contingency, insurance related assessment, discounted amount of premium tax offset The amount of insurance-related assessment liability that is expected to be recovered through premium tax offset (discounted) based on current laws applied to in-force policies. Credit Rating [Axis] Credit Rating [Axis] Credit Rating [Axis] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Share-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Reconciliation of Revenue from Segments to Consolidated [Table] Reconciliation of Revenue from Segments to Consolidated [Table] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Schedule of Interest Rate Fair Value Hedges Hedged Items Schedule of Interest Rate Fair Value Hedges Hedged Items [Table Text Block] [Table Text Block] for Schedule of Interest Rate Fair Value Hedges Hedged Items [Table] Income Taxes [Table] Income Taxes [Table] Income Taxes Limited partnerships investment commitments Limited Partnerships Investment Commitments Outstanding commitments to fund investments in limited partnerships Restricted Stock Activity [Abstract] Restricted Stock Activity [Abstract] Restricted Stock Activity [Abstract] Unpaid policy claims Net balance, beginning of period Net balance, end of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Benefits and claims, excluding reserve remeasurement (gains) losses Policyholder Benefits and Claims Incurred, Excluding Reserve Remeasurement (Gain) Loss Policyholder Benefits and Claims Incurred, Excluding Reserve Remeasurement (Gain) Loss Gross amounts offset in balance sheet Derivative Asset, Security Purchased under Agreement to Resell, and Security Borrowed, Subject to Master Netting Arrangement, Liability Offset .300% senior notes due September 2025 Senior Notes Point Three Zero Zero Percent Due September Twenty Twenty Nine [Member] Yen-denominated senior notes .300% due September 2029 Long-term incentive plan awards, term (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period CC Credit Rating CC Credit Rating [Member] CC Credit Rating Equity securities, FV-NI, unrealized gain (loss) Equity Securities, FV-NI, Unrealized Gain (Loss) Japan government and agencies Debt Security, Government, Non-US [Member] Weighted Average Debt Service Coverage Ratio Weighted Average Debt Service Coverage Ratio Weighted Average Debt Service Coverage Ratio REINSURANCE Reinsurance [Text Block] Financial instruments, amount of liabilities offset against collateral Derivative Liability, Security Sold under Agreement to Repurchase, and Security Loaned, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Derivative liability, fair value, amount offset against collateral Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Other, net Proceeds from (Payments for) Other Financing Activities Derivative, collateral, obligation to return cash Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Total incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Principal payments under debt obligations Repayment of Long-Term Debt, Long-Term Lease Obligation, and Capital Security Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred Exchange [Domain] Exchange [Domain] Credit Facility [Axis] Credit Facility [Axis] Available-for-sale fixed maturity securities Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Public utilities Public Utility, Bonds [Member] Dollar-denominated United States of America, Dollars Change in foreign exchange Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation Subsequent Event [Table] Subsequent Event [Table] Vested Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Entity Tax Identification Number Entity Tax Identification Number Share-based compensation arrangement by share-based payment award, maximum number of shares issuable Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized 1.159% senior notes due October 2030 Senior Notes One Point One Five Nine Percent Due October Twenty Thirty [Member] Senior Notes One Point One Five Nine Percent Due October Twenty Thirty Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Schedule of Investments [Table] Schedule of Investments [Table] Equity securities Proceeds from Sale of Equity Securities, FV-NI Prior year claims and claims adjustment expense from refinement of 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derivatives, amortized cost Derivative liabilities amortized cost disclosure Derivative liabilities amortized cost disclosure Consolidated Entities [Domain] Consolidated Entities [Domain] Debt instrument, debt default, amount Debt Instrument, Debt Default, Amount Other dispositions Stock Issued During Period, Shares, Other Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Equity Instruments Other Than Options Restricted Stock Units [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Equity Instruments Other Than Options Restricted Stock Units [Table] Schedule of Share based Compensation Arrangements by Share based Payment Award, Equity Instruments, Other Than Options, Restricted Stock Units [Table] Net realized gains (losses) recognized for fair value hedge Gain (Loss) on Fair Value Hedge Ineffectiveness, Net Net change in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Entity Central Index Key Entity Central Index Key Foreign currency gains (losses) Foreign currency translation gains (losses) on remeasurement of monetary assets Foreign currency translation gains (losses) on remeasurement of monetary assets Other comprehensive income (loss) before income taxes: Other Comprehensive Income (Loss), before Tax [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] City Area Code City Area Code Assets: Assets [Abstract] 2.144% senior notes due September 2052 Senior Notes Two Point One Four Four Percent Due September Twenty Fifty Two [Member] Senior Notes Two Point One Four Four Percent Due September Twenty Fifty Two Transition Adjustments Revision of Prior Period, Adjustment [Member] Sovereign and supranational Sovereign Debt [Member] Investments Gross Unrealized Loss Aging Schedule of Unrealized Loss on Investments [Table Text Block] Amount of years left to meet 15 year service requirement for active employees age 55 or older to be eligible for postretirement medical benefits Amount of years left to meet fifteen year service requirement for active employees age fifty five or older to be eligible for postretirement medical benefits Amount of years left to meet 15 year service requirement for active employees age 55 or older to be eligible for postretirement medical benefits Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Increase in deferred profit liability Increase (Decrease) in Deferred Revenue Under LDTI Using Spot FX Rate As Of Period End Increase (Decrease) in Deferred Revenue Under LDTI Using Spot FX Rate As Of Period End (Addition to) release of allowance for credit losses) Reinsurance Recoverable, Allowance for Credit Loss, Period Increase (Decrease) BB Credit Rating BB Credit Rating Member [Member] BB Credit Rating Member [Member] Unrealized foreign currency translation gains (losses) during period Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Yen-denominated loan variable interest rate due August 2029 Yen-denominated Loan Variable Interest Rate Due August Twenty Twenty Nine [Member] Yen-denominated Loan Variable Interest Rate Due August Twenty Twenty Nine 1.594% senior notes due September 2037 Senior Notes One Point Five Nine Four Percent Due September Twenty Thirty Seven [Member] Senior Notes One Point Five Nine Four Percent Due September Twenty Thirty Seven Variable Rate [Axis] Variable Rate [Axis] Loan Commitments, Allowance for Credit Loss Off-Balance-Sheet, Credit Loss, Liability Costs of investments acquired: Payments to Acquire Investments [Abstract] Long-Term Incentive Plan Long-Term Incentive Plan Member [Member] Long-Term Incentive Plan Member [Member] Other policyholders' funds fair value disclosure Other policyholders' funds fair value disclosure Other policyholders' funds fair value disclosure Outsourcing agreement, aggregate remaining cost Long-Term Purchase Commitment, Amount Reclassification adjustment for (gains) losses on fixed maturity securities included in net earnings Other Comprehensive Income Reclassification Adjustment For Sale And Write Down Of Securities Included In Net Income Before Tax Pre tax reclassification adjustment for gains or losses realized upon the sale of securities and losses realized upon the write-down of securities. 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Includes the change during the period in any unrealized gain or loss on such investments. Line of credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Loss contingency, loss in period Loss Contingency, Loss in Period 2020 Originated Two Years before Latest Fiscal Year [Member] Originated Two Years before Latest Fiscal Year [Member] Other, net Payments for (Proceeds from) Other Investing Activities Internal valuation technique Internal valuation technique [Member] Internal valuation technique Statistical Measurement [Domain] Statistical Measurement [Domain] Gains (losses) on derivatives excluded from effectiveness testing Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net Aflac U.S. Aflac US [Member] Aflac U.S. Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Allowance for Loan Losses by Portfolio Segment [Roll Forward] Allowance for Loan and Lease Losses [Roll Forward] Net periodic (benefit) cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations Purchases of treasury stock Common stock, share repurchase, dollar amount Treasury Stock, Value, Acquired, Cost Method Blended statutory income tax rate Blended U.S. and Japan Statutory Tax Rate Blended U.S. and Japan Statutory Tax Rate Net earnings Net earnings Net of tax Net Income (Loss) Attributable to Parent Securities lending, carrying value of financial instruments, liabilities not offset in balance sheet Security Loaned, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset Due after one year through five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Fixed maturity securities Debt Securities [Member] Inflation Reduction Act, Excise Tax on Share Repurchases Inflation Reduction Act, Excise Tax on Share Repurchases Inflation Reduction Act, Excise Tax on Share Repurchases Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Axis] .550% senior notes due March 2030 Senior Notes Point Five Five Zero Percent Due March Twenty Thirty [Member] Yen-denominated senior notes .550% due March 2030 Scenario [Axis] Scenario [Axis] Liability for Unpaid Claims and Claims Expenses Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Assets, fair value Total assets Assets, Fair Value Disclosure Equity Securities, FV-NI [Line Items] Debt and Equity Securities, FV-NI [Line Items] Shareholder dividend reinvestment Shareholder Dividend Reinvestment [Member] Shareholder Dividend Reinvestment [Member] Notes payable and lease obligations Debt and Lease Obligation Securities lending, financial instruments, amount of assets offset against collateral Security Borrowed, Including Not Subject to Master Netting Arrangement, after Offset and Deduction 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 Investments Classified by Contractual Maturity Date [Line Items] Investment Holdings [Line Items] Investment Holdings [Line Items] Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Investments, Unrealized Loss Position [Table] Investments, Unrealized Loss Position [Table] Investments, Unrealized Loss Position [Table] Closed Block Closed block [Member] Closed block Member Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Level 1 Fair Value, Inputs, Level 1 [Member] Consensus pricing valuation technique Valuation Technique, Consensus Pricing Model [Member] Prior year claims and claims adjustment expense excluding effect of foreign currency Prior Year Claims And Claims Adjustment Expense Excluding Effect Of Foreign Currency Prior Year Claims And Claims Adjustment Expense Excluding Effect Of Foreign Currency Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales $50 million line of credit Fifty million dollar line of credit [Member] Fifty million dollar line of credit [Member] Percentage of the Company's total revenues Percentage of Company Revenue Percentage of Company Revenue. Net cash provided (used) by operating activities Net Cash Provided by (Used in) Operating Activities Asset derivatives Net amount of derivative assets presented in balance sheet Derivative Asset Net asset value valuation technique Net Asset Value Valuation Technique [Member] Net Asset Value Valuation Technique [Member] Available-for-Sale Debt Securities Debt Securities, Available-for-Sale [Table Text Block] NOTES PAYABLE AND LEASE OBLIGATIONS Debt and Lease Disclosures [Text Block] Debt and Lease Disclosures Other Other Liabilities Net periodic (benefit) cost, excluding service cost Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Other Investments [Abstract] Other Investments [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Securities lending, gross amounts of recognized financial instruments, offsetting liabilities Securities Loaned, Gross Including Not Subject to Master Netting Arrangement Derivative asset, fair value, amount offset against collateral, subject to master netting agreement Derivative Asset, Subject to Master Netting Arrangement, after Offset and Deduction Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] 2022 Current Fiscal Year [Member] Current Fiscal Year Income taxes applicable to pretax adjusted earnings Income taxes applicable to pretax adjusted earnings Income taxes applicable to pretax adjusted earnings Derivative instruments, cash flow hedges, gains (losses) reclassified from accumulated other comprehensive income into earnings Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Geographical [Axis] Geographical [Axis] Write-offs, net of recoveries Reinsurance, Loss on Uncollectible Accounts in Period, Amount Hedge income Derivative, Hedge Income The benefit (income) of a hedge, recognized during the period. Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Securities lending, net amounts of financial instruments presented in balance sheet, offsetting liabilities Securities Loaned Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Derivative, collateral, right to reclaim securities Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Statement, Business Segments [Axis] Segments [Axis] Insurance Product Line [Domain] Product and Service [Domain] Other investments Other Investments Carried at Fair Value, Fair Value Disclosure Other Investments Carried at Fair Value, Fair Value Disclosure Entity Shell Company Entity Shell Company Net investment gains (losses) included in earnings Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Total credit losses Total Credit Losses, Period Increase (Decrease) Total Credit Losses, Period Increase (Decrease) Direct premium income Direct Premiums Earned Gain (Loss) on Securities [Line Items] Gain (Loss) on Securities [Line Items] Financial Instrument [Axis] Financial Instrument [Axis] Other investments Other Investments Adjusted net investment income Adjusted net investment income Amount, after investment expense, net interest cash flows from derivatives associated with certain investment strategies and amortized hedge costs, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes net gain (loss) on investments. Total policy liabilities Total policy liabilities Total Policy Liabilities Total policy liabilities includes future policy benefits, unpaid policy claims, unearned premiums and other policyholders' funds. Subsequent Event Subsequent Event [Member] Amount of years active employees have left to meet rule of 80 in order to be eligible for postretirement medical benefits Amount of years left to meet rule of eighty for active employees to be eligible for postretirement medical benefits The amount of years active employees have left to meet the rule of 80 in order to be eligible for postretirement medical benefits. Consolidation Items [Domain] Consolidation Items [Domain] Allowance for Loan Losses by Portfolio Segment [Abstract] Allowance for Loan Losses by Portfolio Segment [Abstract] Allowance for Loan Losses by Portfolio Segment [Abstract] Document Period End Date Document Period End Date Information Technology and Data Services Company Application Maintenance and Development Services Information Technology and Data Services Company Application Maintenance and Development Services First Agreement [Member] Information Technology and Data Services Company Application Maintenance and Development Services First Agreement OTC- Cleared Exchange Cleared [Member] Fair Value Assets Held-To-Maturity Securities Primary Pricing Sources Fair Value Assets Held-To-Maturity Securities Primary Pricing Sources [Table Text Block] Fair Value Assets Held-To-Maturity Securities Primary Pricing Sources [Table Text Block] Changes in Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Total assets Total assets Assets Income Taxes [Line Items] Income Taxes [Line Items] Income Taxes Investments and Cash: Investments and Cash [Abstract] Change in foreign exchange Reinsurance Recoverable, Allowance for Credit Loss, Foreign Currency Translation Amount of foreign currency translation gain (loss) which decreases (increases) allowance for credit loss on reinsurance recoverables. 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Forward bond purchase commitment Forward Contracts [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Short-term investments Short-Term Investments [Member] Share-based Compensation Arrangements by Share-based Payment Award, Award Type [Domain] Award Type [Domain] Award Type [Domain] Expense on extinguishment of debt Gain (Loss) on Extinguishment of Debt 2020 Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year Ceded benefits and claims Policyholder Benefits and Claims Incurred, Ceded Repurchase Agreements and Repurchase-to-Maturity Transactions Outstanding Repurchase Agreements and Repurchase-to-Maturity Transactions Outstanding Repurchase Agreements and Repurchase-to-Maturity Transactions Outstanding Net investment hedge Net Investment Hedging [Member] Maximum Length of Time Hedged in Cash Flow Hedge Maximum Length of Time Hedged in Cash Flow Hedge Net Effect on Shareholders' Equity of Unrealized Gains and Losses from 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[Axis] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Securities lending, carrying value of financial instruments not offset in balance sheet Security Borrowed, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Percent change in ceded reserves Percent change in ceded reserves Percent change in ceded reserves Treasury Stock Activity By Type [Axis] Treasury Stock Activity By Type [Axis] Treasury Stock Activity By Type [Axis] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Income (loss) from federal historic rehabilitation and solar tax credit investments Income (Loss) from Federal Historic Rehabilitation and Solar Tax Credit Investments Income (Loss) from Federal Historic 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Six hundred million yen line of credit [Member] Six hundred million yen line of credit Concentration Risk Type [Domain] Concentration Risk Type [Domain] Treasury stock Treasury Stock Treasury Stock [Member] Total shareholders’ equity Balance, beginning of period Balance, end of period Total shareholders’ equity Stockholders' Equity Attributable to Parent DERIVATIVE INSTRUMENTS Derivative Instruments and Hedging Activities Disclosure [Text Block] Cancelled Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Vesting [Domain] Vesting [Domain] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Commercial mortgage and other loans Total net commercial mortgage and other loans Financing Receivable, after Allowance for Credit Loss Credit Losses Allowance for Credit Loss [Abstract] Health insurance Accident and Health Insurance Product Line [Member] Mortgage- and asset-backed securities Debt Securities, Held-to-Maturity, Maturity, without Single Maturity Date, Fair Value Dividends paid to shareholders Payments of Dividends Retained earnings Retained Earnings [Member] Dividends to shareholders Dividends, Common Stock, Cash Common stock Common Stock [Member] Net amounts of financial instruments presented in balance sheet, offsetting liabilities Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned Number of reportable insurance business segments Number of Reportable Segments Shares available for future grants under the long-term incentive plan Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant $1 billion line of credit One billion dollar line of credit [Member] One billion dollar line of credit [Member] Schedule of Nonvested Restricted Stock Units Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Securities lending, gross amounts offset in balance sheet Security Borrowed, Subject to Master Netting Arrangement, Liability Offset Statement [Table] Statement [Table] Vested Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Gross gains from sales Equity Method Investment, Realized Gain (Loss) on Disposal Financing Receivable, Credit Quality Indicator [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Derivative liability, fair value, gross liability including not subject to master netting arrangement Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement Fair Value Measurement Inputs and Valuation Techniques Fair Value 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(Loss) Held to maturity: Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity [Abstract] Change in unrealized gains (losses) still held Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 1.039% senior notes due April 2036 Senior Notes One Point Zero Three Nine Percent Due April Twenty Thirty Six [Member] Senior Notes One Point Zero Three Nine Percent Due April Twenty Thirty Six Revision of Prior Period [Domain] Revision of Prior Period [Domain] Fair Value Hierarchy Levels of Assets and Liabilities Carried at Cost or Amortized Cost Schedule Of Fair Value Of Assets And Liabilities Carried At Cost With Fair Values Disclosed [Table Text Block] Tabular disclosure of assets and liabilities, including [financial] instruments, carried at cost or amortized cost whose fair values are only disclosed. The disclosures contemplated herein include the fair value at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). 4.750% senior notes due January 2049 Senior Notes Four Point Seven Five Zero Percent Due January Twenty Forty Nine [Member] Senior Notes Four Point Seven Five Zero Percent Due January Twenty Forty Nine Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-Term Purchase Commitment, Category of Item Purchased [Domain] Statement [Line Items] Statement [Line Items] Direct benefits and claims Policyholder Benefits and Claims Incurred, Direct Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number, shares Beginning Balance Ending Balance Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number 1.122% senior notes due December 2039 Senior Notes One Point One Two Two Percent Due December Twenty Thirty Nine [Member] Senior Notes One Point One Two Two Percent Due December Twenty Thirty Nine [Member] Variable Rate [Domain] Variable Rate [Domain] Accumulated other comprehensive income (loss): Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Effects of Reinsurance [Line Items] Effects of Reinsurance [Line Items] Insurance and other expenses Selling, General and Administrative Expense Securities Lending Transactions Accounted for as Secured Borrowings Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table Text Block] Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Net investment gains (losses) Gain Loss On Investments Excluded From Adjusted Revenue Gain Loss On Investments Excluded From Adjusted Revenue Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Document Transition Report Document Transition Report Loan commitments Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) Local Phone Number Local Phone Number $250 million line of credit Two hundred fifty million dollar line of credit [Member] Two hundred fifty million dollar line of credit [Member] Pretax adjusted earnings Operating Income (Loss) 1.320% senior notes due December 2032 Senior Notes One Point Three Two Zero Percent Due December Twenty Thirty Two [Member] Senior Notes One Point Three Two Zero Percent Due December Twenty Thirty Two Held to maturity securities transferred to available for sale securities, number of investments Held to Maturity Securities Transferred to Available for Sale Securities Number of Investments Number of investments reclassified during the period from the held-to-maturity portfolio to the available-for-sale portfolio. Accounting Standards Update 2018-12 Accounting Standards Update 2018-12 [Member] Life insurance Life Insurance Product Line [Member] Liabilities, fair value Total liabilities Liabilities, Fair Value Disclosure Adjustments to reconcile net earnings to net cash provided (used) by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Performance based Vesting Condition Performance Based Vesting Condition Member Performance-based Vesting Condition Securities collateral, liabilities not offset in balance sheet Derivative Liability, Security Sold under Agreement to Repurchase, and Security Loaned, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Pension liability adjustment, prior service (cost) credit Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Income Statement [Abstract] Income Statement [Abstract] Additional paid-in capital Additional Paid-in Capital [Member] Document Fiscal Period Focus Document Fiscal Period Focus Derivative Instruments and Hedging Activities Disclosure [Line Items] Derivative [Line Items] Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Reconciliation of Adjusted Profit (Loss) from Segments to Consolidated [Table] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Insurance Loss Reserves [Abstract] Insurance Loss Reserves [Abstract] Cash dividends per share Common Stock, Dividends, Per Share, Cash Paid Granted Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Write-offs, net of recoveries Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff Fair Value Hierarchy, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Options Exercisable - Aggregate Intrinsic Value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value Liability for Future Policy Benefit, by Product Segment [Table] Liability for Future Policy Benefit, by Product Segment [Table] 3.625% senior notes paid May 2021 Senior Notes Three Point Six Two Five Percent Due June Twenty Twenty Three [Member] Senior Notes Three Point Six Two Five Percent Due June Twenty Twenty Three 1.560% senior notes due April 2051 Senior Notes One Point Five Six Zero Percent Due April Twenty Fifty One [Member] Senior Notes One Point Five Six Zero Percent Due April Twenty Fifty One COMMITMENTS AND CONTINGENT LIABILITIES Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Foreign currency forwards Foreign Exchange Forward [Member] Investments, Unrealized Loss Position [Line Items] Investments, Unrealized Loss Position [Line Items] Investments, Unrealized Loss Position [Line Items] Common stock, shares issued (in shares) Balance, beginning of period Balance, end of period Common Stock, Shares, Issued Government and agencies Government and Agencies Debt Securities [Member] Government and Agencies Debt Securities Cash collateral, liabilities not offset in balance sheet Derivative Liability, Security Sold under Agreement to Repurchase, and Security Loaned, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset .932% senior notes due January 2027 Senior Notes Point Nine Three Two Percent Due January Twenty Twenty Seven [Member] Yen-denominated senior notes .932% due January 2027 Assets fair value disclosure financial instruments carried at cost Assets Fair Value Disclosure Financial Instruments Carried at Cost This element represents assets reported on the balance sheet that are carried at cost or amortized cost but for which fair value is disclosed. Equity securities, FV-NI Debt Securities, Trading, and Equity Securities, FV-NI [Table Text Block] Securities lending, cash collateral, liabilities not offset in balance sheet Security Loaned, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset Cash flow hedges Cash Flow Hedging [Member] Prior Financing Receivable, Originated, More than Five Years before Current Fiscal Year Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Net cash provided (used) by investing activities Net Cash Provided by (Used in) Investing Activities Total financial instruments assets not carried at fair value Total Financial Instrument Assets Not Carried at Fair Value Total Financial Instrument Assets Not Carried at Fair Value Debt instrument, principal amount Debt Instrument, Face Amount Corporate and other Corporate and Other [Member] Total comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Allowance for Loan Losses by Portfolio Segment Loans and Leases Receivable Disclosure [Table] Entity Current Reporting Status Entity Current Reporting Status Increase in deferred profit liability Increase (Decrease) in Deferred Revenue Under LDTI Using Average FX Rate Increase (Decrease) in Deferred Revenue Under LDTI Using Average FX Rate U.S. federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Japan JAPAN Unrealized gains (losses) on securities available for sale Debt Securities, Available-for-Sale, Unrealized Gain (Loss) Securities lending, securities collateral, liabilities not offset in balance sheet Security Loaned, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Treasury stock reissued Stock Issued During Period, Value, Treasury Stock Reissued Derivative Instruments and Hedging Activities Disclosure [Table] Derivative [Table] Options Outstanding - Stock Option Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Net amount of derivative assets presented in balance sheet Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral Securities lending, cash collateral, not offset in balance sheet Security Borrowed, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Liabilities: Liabilities: Liabilities [Abstract] Property and equipment, at cost less accumulated depreciation Property, Plant and Equipment, Net Commercial mortgage loans Commercial mortgage loans [Member] Commercial mortgage loans [Member] 2021 Originated in Fiscal Year before Latest Fiscal Year [Member] Originated in Fiscal Year before Latest Fiscal Year [Member] Other purchases Other Additions During Period Shares Other additions to number of shares during period. Notes payable Notes Payable, Other Payables [Member] Canceled Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Other income (loss) Other Nonoperating Income (Expense) Percentage that the lending policy requires that the fair value of the securities received as collateral be of the fair value of the loaned securities Collateral Requirements Minimum Securities Percentage Collateral to Fair Value of Securities Loaned Under Security Lending Transactions Percentage that the lending policy requires that the fair value of the securities received as collateral be of the fair value of the loaned securities in securities lending transactions. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Zero-credit-loss expectation Financial Asset Acquired and No Credit Deterioration [Member] Health care plan, number of years of service for eligibility Postretirement Medical Benefits Number Of Years Of Service For Eligibility Postretirement Medical Benefits Number Of Years Of Service For Eligibility Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Accumulated other comprehensive income (loss) Balance, beginning of period Balance, end of period Accumulated Other Comprehensive Income (Loss), Net of Tax Reinsurance recoverable and other Reinsurance Recoverable, Credit Loss Expense (Reversal) Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Proceeds from investments sold or matured: Proceeds from Sale, Maturity and Collection of Investments [Abstract] 6.45% senior notes due August 2040 Senior Notes Six Point Four Five Percent Due August Twenty Forty [Member] Senior Notes Six Point Four Five Percent Due August Twenty Forty [Member] Income taxes paid Income Taxes Paid, Net Unrealized gains (losses) on fixed maturity securities: OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, before Tax [Abstract] Entity Small Business Entity Small Business Other investments carried at amortized cost Other Investments Carried at Amortized Cost Other Investments Carried at Amortized Cost Revolving Loans Financing Receivable, Revolving Transitional real estate loans Transitional real estate loans [Member] Transitional real estate loans Dividends to shareholders (in dollars per share) Common Stock, Dividends, Per Share, Declared Revenues: Revenues [Abstract] Reconciliation of Assets from Segment to Consolidated Reconciliation of Assets from Segment to Consolidated [Table Text Block] Treasury stock reissued Proceeds from Sale of Treasury Stock Net earned premiums, principally supplemental health insurance Net earned premiums, principally supplemental health insurance Net earned premiums Premiums Earned, Net Common Stock Issued [Roll Forward] Common Stock Issued [Roll Forward] Common Stock Issued [Roll Forward] Total compensation cost not yet recognized, restricted stock awards Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Tax benefit from exercise of stock options Share-Based Payment Arrangement, Exercise of Option, Tax Benefit Debt-to-Value [Axis] Debt-to-Value [Axis] Options Outstanding - Aggregate Intrinsic Value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Retirement Plan Sponsor Location [Domain] Consolidated Entities [Axis] Consolidated Entities [Axis] .633% senior notes due April 2031 Senior Notes Point Six Three Three Percent Due April Twenty Thirty One [Member] Senior Notes Point Six Three Three Percent Due April Twenty Thirty One Debt Instrument [Line Items] Debt Instrument [Line Items] Derivative and non-derivative hedging instruments, gain (loss) recognized in other comprehensive income, before tax Derivative and non-derivative hedging instruments gain (loss) recognized in other comprehensive income effective portion before tax Derivative and non-derivative hedging instruments gain (loss) recognized in other comprehensive income effective portion before tax Inflation Reduction Act, Alternative Minimum Corporate Tax Rate Inflation Reduction Act, Alternative Minimum Corporate Tax Rate Inflation Reduction Act, Alternative Minimum Corporate Tax Rate Exercise of stock options and issuance of restricted shares Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Fair Value Measurement Inputs and Valuation Techniques Fair Value Measurement Inputs and Valuation Techniques [Line Items] Operating lease obligations Operating Lease, Liability Fixed maturity securities available for sale (Addition to) release of allowance for credit losses Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease) Gains (losses) recognized in income on derivative Derivative, Gain (Loss) on Derivative, Net Stockholders Equity Note [Table] Stockholders Equity Note [Table] Stockholders Equity Note [Table] NEW YORK STOCK EXCHANGE, INC. NEW YORK STOCK EXCHANGE, INC. [Member] Available for sale, fixed maturity securities, amortized cost Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost Investment Exposures Individually Exceeded Ten Percent of Shareholders' Equity [Table] Investment Exposures Individually Exceeded Ten Percent of Shareholders' Equity [Table] Investment Exposures Individually Exceeded Ten Percent of Shareholders' Equity [Table] Policy Liabilities: Policy liabilities [Abstract] Policy liabilities [Abstract] Fair Value Assets Securities Carried At Fair Value Primary Pricing Sources Fair Value Assets Securities Carried At Fair Value Primary Pricing Sources [Table Text Block] Fair Value Assets Securities Carried At Fair Value Primary Pricing Sources Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Debt Securities, Held-to-maturity [Table] Debt Securities, Held-to-Maturity [Table] Impairment losses Other than Temporary Impairment Losses, Investments Gross amounts offset in statement of financial position, offsetting liabilities Derivative Liability, Security Sold under Agreement to Repurchase, and Security Loaned, Subject to Master Netting Arrangement, Asset Offset Held-to-maturity, fixed maturity securities, allowance for credit losses Allowance for Credit Loss Balance, beginning of period Balance, end of period Debt Securities, Held-to-Maturity, Allowance for Credit Loss .500% senior notes due December 2029 Senior Notes Point Five Zero Zero Percent Due December Twenty Twenty Nine [Member] Senior Notes Point Five Zero Zero Percent Due December Twenty Twenty Nine [Member] Hedging Relationship [Domain] Hedging Relationship [Domain] Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block] Offsetting Assets [Table] Offsetting Assets [Table] Entity Filer Category Entity Filer Category Gross amount of liabilities offset in balance sheet Derivative Asset, Subject to Master Netting Arrangement, Liability Offset U.S. UNITED STATES Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] 500 million yen line of credit Five hundred million yen line of credit [Member] Five hundred million yen line of credit [Member] Liabilities: Liabilities, Fair Value Disclosure [Abstract] Noncash financing activities: Noncash Investing and Financing Items [Abstract] Commitments and contingent liabilities (Note 13) Commitments and contingent liabilities Commitments and Contingencies Securities lending, gross amounts of recognized financial instruments Securities Borrowed, Gross Including Not Subject to Master Netting Arrangement Security Exchange Name Security Exchange Name Options Outstanding - Weighted-Average Exercise Price Per Share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Amortization of deferred policy acquisition costs Deferred Policy Acquisition Costs, Amortization Expense Treasury stock issued Stock Issued Reconciliation of Revenue from Segments to Consolidated Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Derivative liability, fair value, amount offset against collateral, subject to master netting agreement Derivative Liability, Subject to Master Netting Arrangement, after Offset and Deduction Service cost Defined Benefit Plan, Service Cost 3.60% senior notes due April 2030 Senior Notes Three Point Six Zero Percent Due April Twenty Thirty [Member] Senior Notes Three Point Six Zero Percent Due April Twenty Thirty Loan to Value Ratio, 0.00% to 59.99% Loan to Value Ratio, Zero to Fifty-nine Point Nine-nine Percent [Member] Loan to Value Ratio, Zero to Fifty-nine Point Nine-nine Percent [Member] Loss contingency accrual, insurance-related assessment, discount rate Loss Contingency Accrual, Insurance-related Assessment, Discount Rate Cover [Abstract] Cover [Abstract] Yen-denominated loan variable interest rate due August 2027 Yen-denominated Loan Variable Interest Rate Due August Twenty Twenty Seven [Member] Yen-denominated Loan Variable Interest Rate Due August Twenty Twenty Seven Other Other Assets Pension liability adjustment, actuarial gains (losses) Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Health care plan, retirement age and years of service combined years for eligibility (rule of 80) Postretirement Medical Benefits Qualifying Age And Service Period Combined Retirement age and years of service combined years for eligibility for postretirement medical benefits. 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