Intangible assets, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Schedule of Classification of Corporate Investments on the Consolidated Balance Sheets Schedule Of Corporate Investments Text Block [Table Text Block] This element represents the carrying amounts of all corporate investments on the Consolidated Balance Sheets including cash and cash equivalents, short-term and long-term investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. This element excludes same type of investments held as funds held for clients which is disclosed in a separate table. Direct pass-through costs PEO revenues Direct Pass Through Costs P E O Revenues Direct pass-through costs associated with PEO, primarily consisting of payroll wages and payroll taxes. Statistical Measurement [Domain] Statistical Measurement [Domain] Maturities of short-term funding agreements (up to) Maturities Of Short Term Funding Agreements Maturities Of Short-Term Funding Agreements Schedule of Debt Securities, Available-for-Sale Debt Securities, Available-for-Sale [Table Text Block] Contract Liability Change In Contract With Customer, Liability [Roll Forward] Change In Contract With Customer, Liability [Roll Forward] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Schedule of Borrowings under Commercial Paper Program Commercial Paper Program [Table Text Block] Details of the borrowings under the commercial paper program Award Timing Predetermined Award Timing Predetermined [Flag] Three months ending June 30, 2026 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Expected tax deductible amount Business Combination, Goodwill, Expected Tax Deductible, Amount Entity File Number Entity File Number Capital in Excess of Par Value Additional Paid-in Capital [Member] Restricted short-term and long term marketable securities held to satisfy client funds obligations Debt Securities, Available-for-Sale, Restricted Other (Income)/Expense, Net Other Income and Other Expense Disclosure [Text Block] Tabular List, Table Tabular List [Table Text Block] Leases [Abstract] Leases [Abstract] Line of credit facility potentially available increase in maximum borrowing capacity Line Of Credit Facility Potentially Available Increase In Maximum Borrowing Capacity Line of credit facility potentially available increase in maximum borrowing capacity. Funds held for clients Total funds held for clients Funds Held Clients Represents assets that, based upon the Company's intent, are restricted for use solely for the purposes of satisfying the obligations to remit funds relating to the Company’s payroll and payroll tax filing services Effect of Employee Restricted Stock Shares (in shares) Effect of Employee Restricted stock Shares On Weighted Average Number of Diluted Shares Outstanding Effect of Employee Restricted stock Shares On Weighted Average Number of Diluted Shares Outstanding New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Account Classification [Axis] Account Classification [Axis] Account Classification [Axis] Goodwill [Line Items] Goodwill [Line Items] Available-for-sale, Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Net (gain)/loss on ADP Ventures' investments Gain (Loss) On Alternative Investment Gain (Loss) On Alternative Investment Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] BASIC EARNINGS PER SHARE (in dollars per share) Basic, EPS (in dollars per share) Earnings Per Share, Basic Adjustment to Compensation: Adjustment to Compensation [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Commercial Paper Program Commercial Paper [Member] Revenue Revenue from Contract with Customer [Text Block] (Decrease)/increase in accounts payable Increase (Decrease) in Accounts Payable, Trade Stock, Class of Stock [Table] Stock, Class of Stock [Table] Other comprehensive income/(loss), net of tax Other comprehensive income/(loss) Other Comprehensive Income (Loss), Net of Tax Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Reclassification of pension liability adjustment to net earnings Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax Adjustment to Compensation, Amount Adjustment to Compensation Amount Less: unamortized discount and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Increase in other assets Increase (Decrease) in Other Operating Assets Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Employee Stock Option Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Dividends declared Dividends, Common Stock, Cash Total stockholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Tax effect Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Insider Trading Policies and Procedures [Line Items] Total stock-based compensation expense Share-Based Payment Arrangement, Expense Common stock, shares authorized (in shares) Common Stock, Shares Authorized Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Current assets: Assets, Current [Abstract] Total liabilities and stockholders’ equity Liabilities and Equity Net (repurchases)/proceeds from stock-based compensation plans and stock purchase plan Net (Repurchases)/Proceeds From Stock-Based Compensation Plans And Stock Purchase Plan Proceeds from stock plans, stock options exercises, and payments related to tax withholding for share-based compensation. Pension Liability Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Cover [Abstract] Money market securities and other cash equivalents -  Fair Market Value Cash and Cash Equivalents, Fair Value Disclosure Maximum Maximum [Member] Estimated Useful Life (in years) Finite-Lived Intangible Asset, Useful Life Purchase commitments relating to 2027 and 2028 Unrecorded Unconditional Purchase Obligation, To Be Paid, Year One Through Two Unrecorded Unconditional Purchase Obligation, To Be Paid, Year One Through Two Total, Fair Market Value Debt Securities, Available-for-Sale, Unrealized Loss Position Global Global [Member] Global [Member] Schedule of Lessee, Operating Lease, Liability, Maturity Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Non-service components of pension income, net Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Treasury Stock Treasury Stock, Common [Member] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Net lease obligations Operating Lease, Liability U.S. government agency securities U.S. government agency securities US Government Agencies Debt Securities [Member] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Acquisition Business Combination [Text Block] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Fixed-rate 1.700% notes due May 15, 2028 Notes Due On 2028 [Member] Notes Due On 2028 Corporate Investments Corporate Investments [Member] Corporate investments [Member] EARNINGS BEFORE INCOME TAXES Total consolidated earnings before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Other liabilities Other Liabilities, Noncurrent Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Proceeds from the sale of property, plant, and equipment and other assets Proceeds from Sale of Property, Plant, and Equipment Operating Segments Operating Segments [Member] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount Twelve months ending June 30, 2029 Lessee, Operating Lease, Liability, to be Paid, Year Three Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Comprehensive income/(loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Name Measure Name Average outstanding balances (in billions) Short-Term Debt, Average Outstanding Amount One year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Current operating lease liability Operating Lease, Liability, Current Class of Stock [Line Items] Class of Stock [Line Items] Deferred income taxes Deferred Income Tax Liabilities, Net Document Fiscal Period Focus Document Fiscal Period Focus Award Timing Method Award Timing Method [Text Block] Award Type Award Type [Axis] Long-term deferred revenues Contract with Customer, Liability, Noncurrent Currency Translation Adjustment Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Revenues, other than interest on funds held for clients and PEO revenues Revenues, Other Than Interest on Funds Held For Clients and PEO Revenues [Member] Revenues, Other Than Interest on Funds Held For Clients and PEO Revenues 364-day Credit Agreement Three Hundred And Sixty Four Day Credit Facility [Member] Three hundred and sixty four day credit facility [Member] Total assets Assets Twelve months ending June 30, 2027 Finite-Lived Intangible Asset, Expected Amortization, Year One Trading Symbol Trading Symbol Twelve months ending June 30, 2030 Lessee, Operating Lease, Liability, to be Paid, Year Four Entity Address, City or Town Entity Address, City or Town Cash Flows from Operating Activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Other segment expenses Segment Reporting, Other Segment Item, Amount Effect of exchange rate changes on cash, cash equivalents, restricted cash, and restricted cash equivalents Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Report Line [Domain] Statement of Income Location, Balance [Domain] Purchase commitments relating to 2026 Unrecorded Unconditional Purchase Obligation, to be Paid, Remainder of Fiscal Year Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Twelve months ending June 30, 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Four Entity Emerging Growth Company Entity Emerging Growth Company Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Additions to intangibles Payments to Acquire Intangible Assets Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Employer Services Employer Services Employer Services Segment [Member] Employer Services Segment. Deferred contract costs Capitalized Contract Cost, Net Operating expenses Operating Expense [Member] Operating lease ROU assets obtained in exchange for new operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Short-term Financing Short-Term Debt [Text Block] Restricted cash and restricted cash equivalents included in funds held for clients Restricted cash and cash equivalents held to satisfy client funds obligations Restricted Cash and Cash Equivalent Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Business Combination [Domain] Business Combination [Domain] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding WorkForce Software WorkForce Software [Member] WorkForce Software Bad debt expense Accounts Receivable, Credit Loss Expense (Reversal) PEO PEO [Member] Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Interest income on corporate funds Investment Income, Interest Income taxes payable Accrued Income Taxes, Current Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Retained Earnings Retained Earnings [Member] Debt instrument effective rate Debt Instrument, Interest Rate, Effective Percentage Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Cash, cash equivalents, restricted cash, and restricted cash equivalents, beginning of period Cash, cash equivalents, restricted cash, and restricted cash equivalents, end of period Total cash, cash equivalents, restricted cash, and restricted cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Provision for income taxes Income Tax Expense (Benefit) Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Acquisitions of businesses, net of cash acquired Payments for (Proceeds from) Previous Acquisition Other comprehensive income/(loss) before reclassification adjustments OCI, before Reclassifications, before Tax, Attributable to Parent Purchases of corporate and client funds marketable securities Payments to Acquire Marketable Securities Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Intangible assets, net Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Debt instrument, maturity period Debt Instrument, Maturity Period Debt Instrument, Maturity Period Product and Service [Domain] Product and Service [Domain] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Credit Facility Expiring In June 2030 Credit Facility Expiring In June 2030 [Member] Credit Facility Expiring In June 2030 Interest on funds held for clients Interest On Funds Held For Clients [Member] Interest On Funds Held For Clients Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Business Combination [Table] Business Combination [Table] Total corporate investments and funds held for clients - Gross Unrealized Losses Total Corporate Investments And Funds Held For Clients Gross Unrealized Losses Total corporate investments and funds held for clients - gross unrealized losses Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Other Income and Expenses [Abstract] Other Income and Expenses [Abstract] Schedule of Preliminary Purchase Price Allocation Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] City Area Code City Area Code Cash paid for acquisition of business, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Net cash (distributed)/received from the Internal Revenue Service Income Tax Paid, Federal, after Refund Received All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Accrued expenses and other current liabilities Accrued Liabilities, Current Effect of Employee Stock Option Shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Schedule of Contract with Customer, Liability Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Cash Flows from Investing Activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] PEO PEO Services Professional Employee Organization Services Segment [Member] Professional Employee Organization Services Segment [Member] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Net cash flows provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Debt instrument, term Debt Instrument, Term Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Net amortization and deferral Defined Benefit Plan, Amortization of Gain (Loss) Selling, general and administrative expenses Selling, General and Administrative Expenses [Member] Total operating lease cost Lease, Cost Goodwill Balance at June 30, 2025 Balance at March 31, 2026 Goodwill Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Schedule of Lease Cost Lease, Cost [Table Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Money market securities, cash and other cash equivalents Money Market Funds [Member] Three months ending June 30, 2026 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Equity Components [Axis] Equity Components [Axis] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Tax effect Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Number of reportable segments Number of Reportable Segments Employee Benefit Plans Compensation and Employee Benefit Plans [Text Block] Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Available-for-sale, Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost Accounts receivable, net of allowance for doubtful accounts Business Combination, Recognized Asset Acquired, Receivable, Current Other Performance Measure, Amount Other Performance Measure, Amount Less: current portion Debt, Current Currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Entity Address, State or Province Entity Address, State or Province Total current liabilities Liabilities, Current Individual: Individual [Axis] Net (payments)/proceeds related to reverse repurchase agreements Net (Payments Of)/Proceeds From Reverse Repurchase Agreements Net (Payments Of)/Proceeds From Reverse Repurchase Agreements Other current assets Other Assets, Current Research and development Research and Development Expense [Member] Capital in excess of par value Additional Paid in Capital, Common Stock Zero-margin benefits pass-through costs Zero-Margin Benefits Pass-Through Costs Zero-Margin Benefits Pass-Through Costs Net cash flows used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] After four years Available For Sale Securities Debt Maturities Due After Four Fair Value This item represents the fair value of debt securities which are expected to mature after four years of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activity Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Operating lease right-of-use asset Operating Lease, Right-of-Use Asset Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Payments of debt Repayments of Long-Term Debt Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Entity Interactive Data Current Entity Interactive Data Current Other Other Operating Segment [Member] Operating lease cost Operating Lease, Cost Software and software licenses Computer Software, Intangible Asset [Member] Equity [Abstract] Deferred income taxes Deferred Income Tax Expense (Benefit), Net Of Disposals Deferred Income Tax Expense (Benefit), Net Of Disposals Schedule of Components of Stock-Based Compensation Expense Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block] Less segment expenses: Segment Reconciliation [Abstract] Interim Financial Data by Segment Segment Reporting Disclosure [Text Block] Goodwill [Table] Goodwill [Table] U.S. Treasury securities US Treasury Securities [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Currency translation adjustments Contract With Customer, Liability, Increase (Decrease) From Foreign Currency Translation Contract With Customer, Liability, Increase (Decrease) From Foreign Currency Translation Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Revenues from external customers Revenues, Other Than Interest On Funds Held For Client [Member] Revenues, Other Than Interest On Funds Held For Client Schedule of Net Pension (Income) Expense Schedule of Net Benefit Costs [Table Text Block] Other securities Other Other Debt Obligations [Member] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Amortization of intangible assets Amortization of Intangible Assets Obligations under commercial paper borrowings Commercial Paper Selling, general, and administrative expenses Selling, General and Administrative Expense Depreciation and amortization Total depreciation and amortization Depreciation, Depletion and Amortization Reverse repurchase agreements Reverse Repurchase Agreements [Member] Reverse Repurchase Agreements [Member] Other assets Other Assets, Noncurrent Entity Central Index Key Entity Central Index Key Increase in accounts receivable Increase (Decrease) in Accounts and Notes Receivable PEO Name PEO Name Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Schedule of Components of Stockholders' Equity Schedule of Stockholders Equity [Table Text Block] Other comprehensive income/(loss): Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Arrangement Duration Trading Arrangement Duration Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Short-term deferred revenues Contract with Customer, Liability, Current Segments [Axis] Segment Reporting Information, by Segment [Axis] Segments [Axis] Exercise Price Award Exercise Price Canadian provincial bonds Canadian Provincial Bonds [Member] Canadian Provincial Bonds [Member] Entity Filer Category Entity Filer Category Local Phone Number Local Phone Number Client funds obligations Client Funds Obligations Represent the Company's contractual obligations to remit funds to satisfy clients' payroll and tax payment obligations and are recorded on the Balance Sheet at the time that the Company impounds funds from clients. Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Other Payment for (Proceeds from) Other Investing Activity PEO revenues PEO Revenues [Member] PEO Revenues Cash Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent Assets Assets [Abstract] Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Four Lessee, Operating Lease, Liability, to be Paid, after Year Four Long-term debt Total long-term debt Long-Term Debt, Excluding Current Maturities Underlying Security Market Price Change Underlying Security Market Price Change, Percent Twelve months ending June 30, 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Three Schedule of Reverse Repurchase Agreements Reverse Repurchase Agreement [Table Text Block] Details of the reverse repurchase agreement Debt Instrument [Axis] Debt Instrument [Axis] Business Combination [Line Items] Business Combination [Line Items] Intangible assets, gross Finite-Lived Intangible Assets, Gross Stockholders' equity: Equity, Attributable to Parent [Abstract] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Entity Address, Address Line One Entity Address, Address Line One Treasury stock acquired Treasury Stock, Value, Acquired, Cost Method Research and development Research and Development Expense AOCI Accumulated Other Comprehensive Income/(Loss) AOCI Attributable to Parent [Member] Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Allowance for doubtful accounts, current Accounts Receivable, Allowance for Credit Loss, Current Operating lease liabilities Operating Lease, Liability, Noncurrent Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Fair Value as of Grant Date Award Grant Date Fair Value Tax effect Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Entity Registrant Name Entity Registrant Name Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Net pension (income)/expense Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Customer contracts and lists Customer Lists [Member] Municipal Bonds Municipal Bonds [Member] Schedule of Other (Income)/Expense, Net Schedule of Other Nonoperating Income (Expense) [Table Text Block] TOTAL EXPENSES Costs and Expenses Document Quarterly Report Document Quarterly Report Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Fair value of notes issued Long-Term Debt, Fair Value Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Twelve months ending June 30, 2028 Lessee, Operating Lease, Liability, to be Paid, Year Two Net accretion of discounts and amortization of premiums on available-for-sale securities Accretion (Amortization) of Discounts and Premiums, Investments Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Standards Update and Change in Accounting Principle [Abstract] Number of fixed rate notes issued Number Of Fixed Rate Notes Issued Number Of Fixed Rate Notes Issued Schedule of Long Term Debt Schedule of Debt [Table Text Block] Interest cost on projected benefits Defined Benefit Plan, Interest Cost Total corporate investments Investments Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Restatement Determination Date: Restatement Determination Date [Axis] Purchase price Payments to Acquire Businesses, Gross Issuances relating to stock compensation plans Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Non-PEO NEO Non-PEO NEO [Member] Deferred revenue Business Combination, Recognized Liability Assumed, Deferred Revenue, Current Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Other intangibles Other Intangible Assets [Member] Short-term marketable securities under reverse repurchase agreements Short-term Marketable Securities Under Reverse Repurchase Agreements Short-term Marketable Securities Under Reverse Repurchase Agreements Available-for-sale, Gross Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Name Trading Arrangement, Individual Name Contract liability, net of revenue recognized on contracts during the period Contract With Customer, Liability, Deferral Net Of Revenue Recognized And Foreign Currency Translation Amount of revenue deferred as an obligation to transfer good or service to customer for which consideration from customer has been received or is due, net of the amount of revenue recognized in the period from deferrals during the period. All Award Types Award Type [Domain] Twelve months ending June 30, 2027 Lessee, Operating Lease, Liability, to be Paid, Year One Unrealized gains/(losses) on cash flow hedging activities Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Schedule of Short-term Debt [Table] Short-Term Debt [Table] Equity Awards Adjustments Equity Awards Adjustments [Member] Other Other Noncash Income (Expense) Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Debt face amount Debt Instrument, Face Amount Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Operating expenses Operating Costs and Expenses Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Recognition of revenue included in beginning of year contract liability Contract with Customer, Liability, Revenue Recognized Settlement of cash flow hedges Payments for Hedge, Financing Activities Tax effect Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Fixed-rate 4.450% notes due September 9, 2034 Notes Due In 2034 [Member] Notes Due In 2034 MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Name Awards Close in Time to MNPI Disclosures, Individual Name Deferred income taxes, net of valuation allowance Business Combination, Recognized Asset Acquired, Deferred Tax Asset Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Reclassification of realized net (gains)/losses on available-for-sale securities to net earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax REVENUES: Revenues [Abstract] Term of credit Line Of Credit Facility Term Of Credit Line Of Credit Facility Term Of Credit Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Treasury stock - at cost: 238.1 and 233.4 shares at March 31, 2026 and June 30, 2025, respectively Treasury Stock, Value Tax effect OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Accumulated other comprehensive income/(loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Selling and marketing Selling and Marketing Expense Total corporate investments and funds held for clients - Gross Unrealized Gains Total Corporate Investments And Funds Held For Clients Gross Unrealized Gains Total corporate investments and funds held for clients - gross unrealized gains Tax effect Other Comprehensive Income (Loss) before Reclassifications, Tax Financial Instruments [Domain] Financial Instruments [Domain] Reporting Segment [Domain] Segments [Domain] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [Axis] Statement of Income Location, Balance [Axis] Corporate Investments and Funds Held for Clients Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] All other liabilities Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liabilities, Other Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liabilities, Other Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Minimum Minimum [Member] Net Gains/Losses on Available-for-sale Securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Costs of revenues: Cost of Revenue [Abstract] Company Selected Measure Name Company Selected Measure Name Senior Notes Senior Notes [Member] Debt Debt Disclosure [Text Block] Preferred stock, $1.00 par value: authorized, 0.3 shares; issued, none Preferred Stock, Value, Issued Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Accounts payable Accounts Payable, Current Cash paid for operating lease liabilities Operating Lease, Payments HCM HCM [Member] HCM [Member] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Dividends payable Dividends Payable Asset-Backed Auto Loan Receivables Asset Backed Auto Loan Receivables [Member] Securities collateralized by physical property Total liabilities assumed Business Combination, Recognized Liability Assumed, Liability All Executive Categories All Executive Categories [Member] Schedule of Expected Maturities of Available-for-Sale Securities Schedule Of Expected Maturities Of Available For Sale Securities [Table Text Block] This element represents the expected maturities broken out by maturity date of all investments categorized as available-for-sale Common stock, $0.10 par value: authorized, 1,000.0 shares; issued, 638.7 shares at March 31, 2026 and June 30, 2025; outstanding, 400.6 and 405.3 shares at March 31, 2026 and June 30, 2025, respectively Common Stock, Value, Issued Purchase commitments relating to 2029 and 2031 Unrecorded Unconditional Purchase Obligation, To Be Paid, Year Three Through Five Unrecorded Unconditional Purchase Obligation, To Be Paid, Year Three Through Five Total corporate investments and funds held for clients - Amortized Cost Total Corporate Investments And Funds Held For Clients Amortized Cost Total corporate investments and funds held for clients - amortized cost Goodwill [Roll Forward] Goodwill [Roll Forward] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Non-current Non-current [Member] Non-current [Member] Diluted weighted average shares outstanding (in shares) Diluted, Weighted average shares (in shares) Weighted Average Number of Shares Outstanding, Diluted All other assets Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Assets, Other Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Assets, Other Commitments and contingencies (Note 14) Commitments and Contingencies Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Funds Held For Clients Funds Held For Clients [Member] Funds held for clients [Member] Less: cash acquired Cash Acquired from Acquisition Identifiable intangible assets Estimated Fair Value Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Finite-Lived Business Combination [Axis] Business Combination [Axis] Asset-Backed Securities, Device Payment Plan Agreement Receivables Asset-Backed Securities, Device Payment Plan Agreement Receivables [Member] Asset-Backed Securities, Device Payment Plan Agreement Receivables Entity Small Business Entity Small Business Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] One year to two years Available For Sale Securities Debt Maturities Due After One Year Up To Two Fair Value This item represents the fair value of debt securities which are expected to mature after one year up to two years after the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Document Transition Report Document Transition Report New Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Net (payments)/proceeds related to commercial paper Proceeds from (Repayments of) Commercial Paper Underlying Securities Award Underlying Securities Amount Short-term Debt [Line Items] Short-Term Debt [Line Items] Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Income Taxes Income Tax Disclosure [Text Block] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Short-term lease cost Short-Term Lease, Cost Client funds held in grantor trust Client Funds Held In Grantor Trust Client Funds Held In Grantor Trust Document Type Document Type Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Earnings per Share (“EPS”) Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Federal Farm Credit Banks Federal Farm Credit Banks [Member] Federal Farm Credit Banks [Member] Product and Service [Axis] Product and Service [Axis] Amortization of unrealized (gains)/losses on cash flow hedging activities Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Notes payable Notes Payable Variable lease cost Variable Lease, Cost Revenues Revenue from Contract with Customer, Excluding Assessed Tax All Individuals All Individuals [Member] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Reclassifications out of Accumulated Other Comprehensive Income/(Loss) (“AOCI”) Disclosure of Reclassification Amount [Text Block] Name Forgone Recovery, Individual Name Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Credit Facility Expiring In June 2029 Credit Facility Expiring In June 2029 [Member] Credit Facility Expiring In June 2029 Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Capital expenditures Payments to Acquire Other Property, Plant, and Equipment Reconciliation of cash, cash equivalents, restricted cash, and restricted cash equivalents to the Consolidated Balance Sheets Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Currency translation adjustments Goodwill, Foreign Currency Translation, Gain (Loss) Worker's compensation coverage and state unemployment taxes Worker's Compensation Coverage And State Unemployment Taxes Worker's Compensation Coverage And State Unemployment Taxes Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Short-term marketable securities Marketable Securities, Current Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Schedule of Finite-Lived Intangible Assets by Major Class [Table] Intangible Asset, Finite-Lived [Table] Current liabilities: Liabilities, Current [Abstract] Total corporate investments and funds held for clients -  Fair Market Value Total Corporate Investments And Funds Held For Clients Fair Value Total corporate investments and funds held for clients - fair value Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Robert H. Swan [Member] Robert H. Swan Total current assets before funds held for clients Total Assets Before Funds Held Clients Total assets before funds held for clients Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Gain on sale of assets Gain (Loss) on Disposition of Assets Increase/(decrease) in accrued expenses and other liabilities Increase (Decrease) in Accrued Liabilities DILUTED EARNINGS PER SHARE (in dollars per share) Diluted, EPS (in dollars per share) Earnings Per Share, Diluted Depreciation and amortization Cost, Depreciation and Amortization Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Accounts receivable, net of allowance for doubtful accounts of $46.0 and $47.1, respectively Accounts Receivable, after Allowance for Credit Loss, Current Title of 12(b) Security Title of 12(b) Security Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Amortization of deferred contract costs Capitalized Contract Cost, Amortization Treasury stock, shares (in shares) Treasury Stock, Common, Shares Earnings Per Share [Abstract] Earnings Per Share [Abstract] Consolidation Items [Domain] Consolidation Items [Domain] Other (income)/loss, net Other (income)/loss, net Nonoperating Income (Expense) Investments, Debt and Equity Securities [Abstract] Weighted average maturity (approximately in days) Commercial Paper Weight Average Maturity Reflects the calculated weighted average maturity of the Company's commercial paper Schedule of Investment of Funds Held for Clients Schedule Of Investment Of Funds Held For Clients [Table Text Block] This element represents the carrying amounts of all investments of funds held for clients on the Consolidated Balance Sheets including cash and cash equivalents, short-term and long-term investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. Less: Imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Debt Security, Corporate, Non-US Debt Security, Corporate, Non-US [Member] Treasury stock acquired (in shares) Treasury Stock, Shares, Acquired Cash paid for income taxes, net of income tax refunds Income Taxes Paid, Net Twelve months ending June 30, 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Two Award Timing Disclosures [Line Items] Service cost – benefits earned during the period Defined Benefit Plan, Service Cost Accrued payroll and payroll-related expenses Employee-related Liabilities, Current Total undiscounted lease obligations Lessee, Operating Lease, Liability, to be Paid Stockholders' Equity Equity [Text Block] Tradename Trade Names [Member] Weighted average interest rates Debt Instrument, Interest Rate During Period NET EARNINGS Net earnings Net Income (Loss) Attributable to Parent Intercompany eliminations Intersegment Eliminations [Member] Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Expiration Date Trading Arrangement Expiration Date PEO zero-margin benefits pass-throughs PEO Zero-Margin Benefits Pass-Throughs [Member] PEO Zero-Margin Benefits Pass-Throughs Twelve months ending June 30, 2031 Finite-Lived Intangible Asset, Expected Amortization, Year Five Canadian government obligations and Canadian government agency obligations Debt Security, Government, Non-US [Member] Property, plant and equipment, net Property, Plant and Equipment, Net Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Repurchases of common stock Payments for Repurchase of Common Stock Adoption Date Trading Arrangement Adoption Date Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Supranational Bonds Supranational Bonds [Member] Supranational Bonds Federal Home Loan Banks Federal Home Loan Bank Certificates and Obligations (FHLB) [Member] Entity Current Reporting Status Entity Current Reporting Status Remaining lease term Lessee, Operating Lease, Term of Contract Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Extension option term Debt Instrument, Extension Option Term Debt Instrument, Extension Option Term Retained earnings Retained Earnings (Accumulated Deficit) Total current liabilities before client funds obligations Total Current Liabilities Before Client Funds Obligations Total Current Liabilities Before Client Funds Obligations Financial Instrument [Axis] Financial Instrument [Axis] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Executive Category: Executive Category [Axis] Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Current Current [Member] Current [Member] Obligations under reverse repurchase agreements Obligations Under Reverse Repurchase Agreements Obligations Under Reverse Repurchase Agreements Proceeds from the issuance of debt Proceeds from Issuance of Long-Term Debt Interest expense Interest Expense, Operating and Nonoperating Current Fiscal Year End Date Current Fiscal Year End Date Technology Technology-Based Intangible Assets [Member] Cash Flow Hedging Activities Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Net increase in client funds obligations Net Increase (Decrease) In Client Funds Obligations Net (decrease) increase in client funds obligations Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Statement [Table] Statement [Table] Schedule of Estimated Purchase Price, Net of Cash Acquired Business Combination [Table Text Block] Adjustments to reconcile net earnings to cash flows provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Cash Flows from Financing Activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Total net assets acquired Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill Aggregate committed obligations under reverse repurchase agreements Debt Instrument, Aggregate Committed Obligations Under Reverse Repurchase Agreements Debt Instrument, Aggregate Committed Obligations Under Reverse Repurchase Agreements Total, Gross Unrealized Losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Contract liability, July 1, 2025 Contract liability, March 31, 2026 Contract with Customer, Liability Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Options excluded from the calculation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Purchase commitments Unrecorded Unconditional Purchase Obligation All Adjustments to Compensation All Adjustments to Compensation [Member] Amendment Flag Amendment Flag Schedule of Components of Finite-Lived Intangible Assets Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Leases Lessee, Operating Leases [Text Block] Termination Date Trading Arrangement Termination Date Net cash flows provided by/(used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Increase in deferred contract costs Increase (Decrease) in Contract with Customer, Asset Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] Other Corporate And Reconciling Items [Member] Corporate And Reconciling Items Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Fixed Rate Credit Card Fixed Rate Credit Card [Member] Fixed Rate Credit Card [Member] Basic weighted average shares outstanding (in shares) Basic, Weighted average shares (in shares) Weighted Average Number of Shares Outstanding, Basic Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Customer/Partner relationships Customer And Partner Relationships [Member] Customer And Partner Relationships TOTAL COSTS OF REVENUES Cost of Product and Service Sold Schedule of Earnings per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Segment Reporting [Abstract] Segment Reporting [Abstract] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Fixed-rate 4.750% notes due May 8, 2032 Notes Due On 2032 [Member] Notes Due On 2032 Debt Disclosure [Abstract] Debt Disclosure [Abstract] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Entity Tax Identification Number Entity Tax Identification Number EXPENSES: Costs and Expenses [Abstract] Tax effect Reclassification from AOCI, Current Period, Tax Additions and other adjustments Goodwill, Other Increase (Decrease) Reclassification adjustments to net earnings Reclassification from AOCI, Current Period, before Tax, Attributable to Parent Operating Segments, Excluding Intersegment Elimination Operating Segments, Excluding Intersegment Elimination [Member] Operating Segments, Excluding Intersegment Elimination Realized (gains)/losses on available-for-sale securities, net Debt Securities, Available-for-Sale, Realized Gain (Loss) Unrealized net gains/(losses) on available-for-sale securities OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares issued (in shares) Common Stock, Shares, Issued PEO Services Peo Services Segment [Member] PEO Services Segment. Client fund obligation repayment period Client Fund Obligation repayment period Period of time from the Balance Sheet Date that client fund obligations has to be repaid Weighted-average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term Commercial mortgage-backed securities Commercial Mortgage-Backed Securities [Member] Two years to three years Available For Sale Securities Debt Maturities Due After Two Year Up To Three Fair Value This item represents the fair value of debt securities which are expected to mature after two years up to three years of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Goodwill and Intangible Assets, net Goodwill and Intangible Assets Disclosure [Text Block] Line of credit facility, fair value of amount outstanding Line of Credit Facility, Fair Value of Amount Outstanding Dividends paid Payments of Dividends Schedule of Changes in Goodwill Schedule of Goodwill [Table Text Block] Trading Arrangement: Trading Arrangement [Axis] Total assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Acquired Including Goodwill Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Acquired Including Goodwill Total Shareholder Return Amount Total Shareholder Return Amount Three years to four years Available For Sale Securities Debt Maturities Due After Three Year Up To Four Fair Value This item represents the fair value of debt securities which are expected to mature after three years up to four years of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Insider Trading Arrangements [Line Items] Other Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Security Exchange Name Security Exchange Name Total liabilities Liabilities Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Net pension (income)/loss Increase (Decrease) in Obligation, Pension Benefits Client funds investments with original maturities Client Funds Investments Original Maturity Period Client funds investments, maturity period. Maximum borrowing capacity under credit facilities Line of Credit Facility, Maximum Borrowing Capacity Account Classification [Domain] Account Classification [Domain] [Domain] for Account Classification [Axis] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Fixed-rate 1.250% notes due September 1, 2030 Notes Due On 2030 [Member] Notes Due On 2030 Proceeds from the sales and maturities of corporate and client funds marketable securities Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] HRO, excluding PEO zero-margin benefits pass-throughs HRO [Member] HRO [Member] Statement [Line Items] Statement [Line Items] Asset-backed securities Asset-Backed Securities [Member] Consolidation Items [Axis] Consolidation Items [Axis] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Money market securities, cash and other cash equivalents - Amortized Cost Cash and Cash Equivalent Common Stock Common Stock [Member] Available-for-sale, Fair Market Value Debt securities, available-for-sale Total available-for-sale securities Debt Securities, Available-for-Sale Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member] Corporate bonds Corporate Debt Securities [Member] Net change in cash, cash equivalents, restricted cash, and restricted cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation