One year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Schedule Of Corporate Investments Text Block 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. Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Total undiscounted lease obligations Lessee, Operating Lease, Liability, to be Paid Change In Contract With Customer, Liability [Roll Forward] Change In Contract With Customer, Liability [Roll Forward] Change In Contract With Customer, Liability [Roll Forward] Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Commercial Paper Program Commercial Paper Program [Table Text Block] Details of the borrowings under the commercial paper program Entity Address, Postal Zip Code Entity Address, Postal Zip Code Schedule of Components of Stockholders' Equity Schedule of Stockholders Equity [Table Text Block] 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 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 Debt Instrument [Axis] Debt Instrument [Axis] Effect of Employee Restricted Stock Shares (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 Other Other Segments [Member] Maximum borrowing capacity under credit facilities Line of Credit Facility, Maximum Borrowing Capacity Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Account Classification [Axis] Account Classification [Axis] Account Classification [Axis] Currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Other Income and Expenses [Abstract] Other Income and Expenses [Abstract] Other (Income)/Expense, Net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Financial Instruments [Domain] Financial Instruments [Domain] Short-term Financing Short-Term Debt [Text Block] Statistical Measurement [Domain] Statistical Measurement [Domain] Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Capital in excess of par value Additional Paid in Capital, Common Stock Net pension (income)/expense Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Other Other Noncash Income (Expense) Dividends payable Dividends Payable Treasury stock acquired Treasury Stock, Value, Acquired, Cost Method Fixed-rate 3.375% notes due September 15, 2025 Notes due on 2025 [Member] Notes due on 2025 [Member] NET EARNINGS Net earnings Net Income (Loss) Attributable to Parent Options excluded from the calculation of diluted earnings per share (shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Other intangibles Other Intangible Assets [Member] Equity Component [Domain] Equity Component [Domain] Leases Lessee, Operating Leases [Text Block] Fair market value Debt securities, available-for-sale Total available-for-sale securities Debt Securities, Available-for-Sale Systems development and programming costs Systems development programming costs Includes all direct/incremental costs of developing, producing, and maintaining the software used in delivering products. Global Global [Member] Global [Member] Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Deferred contract costs Capitalized Contract Cost, Net Three months ending June 30, 2023 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Goodwill Goodwill [Line Items] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Entity Address, State or Province Entity Address, State or Province Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Notes due on 2028 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] Net cash flows provided by operating activities Net Cash Provided by (Used in) Operating Activities Current operating lease liability Operating Lease, Liability, Current Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Debt Securities, Available-for-Sale Debt Securities, Available-for-Sale [Table Text Block] Non-service components of pension income, net Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Long-term debt Long-Term Debt, Excluding Current Maturities Total liabilities Liabilities Weighted-average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term Amortization of unrealized losses on cash flow hedging activities Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities [Abstract] 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] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Net Gains/Losses on Available-for-sale Securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Standards Update and Change in Accounting Principle [Abstract] Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Document Type Document Type Realized losses/(gains) on available-for-sale securities, net Debt Securities, Available-for-Sale, Realized Gain (Loss) Reconciliation of cash, cash equivalents, restricted cash, and restricted cash equivalents to the Consolidated Balance Sheets Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect [Abstract] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Segments [Axis] Segment Reporting Information, by Segment [Axis] Segments [Axis] Debt Debt Disclosure [Text Block] EXPENSES: Cost of Revenue [Abstract] Employee Benefit Plans Compensation and Employee Benefit Plans [Text Block] Product and Service [Domain] Product and Service [Domain] Entity Shell Company Entity Shell Company Schedule Of Investment Of Funds Held For Clients Text Block Schedule Of Investment Of Funds Held For Clients Text Block [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. (Decrease)/Increase in accrued expenses and other liabilities Increase (Decrease) in Accrued Liabilities Twelve months ending June 30, 2024 Lessee, Operating Lease, Liability, to be Paid, Year One Employer Services Employer Services Segment [Member] Employer Services Segment. Financial Instrument [Axis] Financial Instrument [Axis] Contract with Customer, Liability Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Document Period End Date Document Period End Date Net (decrease)/increase in client funds obligations Net decrease increase in client funds obligations Net (decrease) increase in client funds obligations Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Total assets Assets Debt Disclosure [Abstract] Debt Disclosure [Abstract] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Obligations under reverse repurchase agreements Obligations under reverse repurchase agreements - long term Obligations under reverse repurchase agreements, Long Term Obligations under reverse repurchase agreements, Long Term Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [Axis] Income Statement Location [Axis] Long-term receivables, net of allowance for doubtful accounts of $0.2 and $0.1, respectively Accounts Receivable, after Allowance for Credit Loss, Noncurrent Unrealized net (losses)/gains on available-for-sale securities OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Stock-based compensation expense Stock Based Compensation Expense in Equity Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Accrued expenses and other current liabilities Accrued Liabilities, Current Net cash flows (used in)/provided by financing activities Net Cash Provided by (Used in) Financing Activities Fair value of notes issued Long-Term Debt, Fair Value Accrued payroll and payroll-related expenses Employee-related Liabilities, Current Variable lease cost Variable Lease, Cost Asset-backed securities Asset-Backed Securities [Member] Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] EARNINGS BEFORE INCOME TAXES Earnings before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Reporting Segment [Domain] Segments [Domain] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Reclassification out of Accumulated Other Comprehensive Income [Abstract] Reclassification out of Accumulated Other Comprehensive Income [Abstract] Reclassification out of Accumulated Other Comprehensive Income [Abstract] Earnings per Share (EPS) Earnings Per Share [Text Block] Interest cost on projected benefits Defined Benefit Plan, Interest Cost Components Of Stock-Based Compensation Expense Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block] Municipal Bonds Municipal Bonds [Member] Effect of Employee Stock Option Shares (shares) Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Tax effect OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Total, Gross Unrealized Losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Interest on funds held for clients Interest on Funds Held for Clients [Member] Interest on Funds Held for Clients 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 Entity Registrant Name Entity Registrant Name Debt Security, Corporate, Non-US Debt Security, Corporate, Non-US [Member] Currency translation adjustments Goodwill, Foreign Currency Translation Gain (Loss) Currency Translation Adjustment Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Entity Address, City or Town Entity Address, City or Town Cash Flow Hedging Activities Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] PEO Services Professional Employee Organization Services Segment [Member] Professional Employee Organization Services Segment [Member] Leases [Abstract] Leases [Abstract] Deferred income taxes Deferred Income Tax Expense (Benefit), Net of Disposals Deferred Income Tax Expense (Benefit), Net of Disposals Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Entity Emerging Growth Company Entity Emerging Growth Company Common stock, par value (in US$ per share) Common Stock, Par or Stated Value Per Share Tax effect Other Comprehensive Income (Loss) before Reclassifications, Tax Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Treasury Stock Treasury Stock, Common [Member] Trading Symbol Trading Symbol Entity File Number Entity File Number Treasury stock, shares (in shares) Treasury Stock, Common, Shares Tax effect Reclassification from AOCI, Current Period, Tax Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Twelve months ending June 30, 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Four Long-term deferred revenues Contract with Customer, Liability, Noncurrent Restricted cash and cash equivalents held to satisfy client funds obligations Restricted Cash and Cash Equivalents Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Schedule of Operating Lease ROU Assets and Liabilities Operating lease ROU assets and liabilities [Table Text Block] Supplemental cash flow information related to our operating lease ROU assets and operating lease liabilities [Table Text Block] Money market securities and other cash equivalents - fair market value Cash and Cash Equivalents, Fair Value Disclosure Corporate Investments and Funds Held For Clients Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Income Taxes Income Tax Disclosure [Text Block] 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 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. Amortization of intangible assets Amortization of Intangible Assets Changes In Goodwill Schedule of Goodwill [Table Text Block] Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Operating expenses Operating Costs and Expenses BASIC EARNINGS PER SHARE (in US$ per share) Basic, EPS (in US$ per share) Earnings Per Share, Basic Tax effect Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Twelve months ending June 30, 2026 Lessee, Operating Lease, Liability, to be Paid, Year Three Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Pension Liability Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Total stockholders’ equity Beginning balance Ending balance Stockholders' Equity Attributable to Parent Net payments related to reverse repurchase agreements Net (repayments of)/proceeds from reverse repurchase agreements Net (repayments of)/proceeds from reverse repurchase agreements Entity Interactive Data Current Entity Interactive Data Current Commercial mortgage-backed securities Commercial Mortgage-Backed Securities [Member] Amortization of deferred contract costs Capitalized Contract Cost, Amortization Total - accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Currency translation adjustments Contract With Customer, Liability, Increase (Decrease) From Foreign Currency Translation Contract With Customer, Liability, Increase (Decrease) From Foreign Currency Translation Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Twelve months ending June 30, 2026 Finite-Lived Intangible Asset, Expected Amortization, Year Three Money Market Funds Money Market Funds [Member] Retained Earnings Retained Earnings [Member] Dividends paid Payments of Dividends Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Total funds held for clients Total Funds Held To Satisfy Client Fund Obligation At Carrying Value Sum of the carrying amounts as of the balance sheet date of current and noncurrent investments of funds held for clients. Client fund assets represent 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. Total operating lease cost Lease, Cost Common Stock Common Stock [Member] Short-Term Financing [Abstract] Short-Term Financing [Abstract] Short-term Financing Issuances relating to stock compensation plans Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Number of reportable segments Number of Reportable Segments Reverse repurchase agreements Reverse Repurchase Agreements [Member] Reverse Repurchase Agreements [Member] Schedule of Lease Cost Lease, Cost [Table Text Block] Repurchases of common stock Payments for Repurchase of Common Stock Commercial paper Commercial Paper Statement [Table] Statement [Table] Reclassifications out of Accumulated Other Comprehensive Income (AOCI) Disclosure of Reclassification Amount [Text Block] Debt instrument effective rate (percent) Debt Instrument, Interest Rate, Effective Percentage Long-term marketable securities Marketable Securities, Noncurrent Document Quarterly Report Document Quarterly Report Current assets: Assets, Current [Abstract] Operating lease liabilities Operating Lease, Liability, Noncurrent Statistical Measurement [Axis] Statistical Measurement [Axis] Treasury stock acquired (shares) Treasury Stock, Shares, Acquired Schedule Of Expected Maturities Of Available For Sale Securities Text Block Schedule Of Expected Maturities Of Available For Sale Securities Text Block [Table Text Block] This element represents the expected maturities broken out by maturity date of all investments categorized as available-for-sale Retained earnings Retained Earnings (Accumulated Deficit) Canadian provincial bonds Canadian Provincial Bonds [Member] Canadian Provincial Bonds [Member] Accounts receivable, net of allowance for doubtful accounts of $51.2 and $56.8, respectively Accounts Receivable, after Allowance for Credit Loss, Current Schedule of Finite-Lived Intangible Assets by Major Class [Table] Schedule of Finite-Lived Intangible Assets [Table] Purchases of corporate and client funds marketable securities Payments to Acquire Marketable Securities Equity Components [Axis] Equity Components [Axis] 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. PEO Revenues PEO Revenues [Member] PEO Revenues 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 Tax effect Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Document Fiscal Year Focus Document Fiscal Year Focus Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Four Lessee, Operating Lease, Liability, to be Paid, after Year Four Components Of Finite-Lived Intangible Assets Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Statement [Line Items] Statement [Line Items] Reverse Repurchase Agreement Reverse Repurchase Agreement [Table Text Block] Details of the reverse repurchase agreement Other (income)/expense, net Other (income)/expense, net Nonoperating Income (Expense) Total - gross Finite-Lived Intangible Assets, Gross Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Selling, general, and administrative expenses Selling, General and Administrative Expense Asset-Backed Equipment Lease Receivable Asset-Backed Equipment Lease Receivable [Member] Asset-Backed Equipment Lease Receivable [Member] Credit Facility Expiring In June 2024 Credit Facility Expiring In June Two Thousand Twenty Four [Member] Credit Facility Expiring In June Two Thousand Twenty Four [Member] New Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Operating lease right-of-use asset Operating Lease, Right-of-Use Asset AOCI AOCI Attributable to Parent [Member] Reclassification adjustments to net earnings Reclassification from AOCI, Current Period, before Tax, Attributable to Parent Reclassification of realized net losses/(gains) on available-for-sale securities to net earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Document Transition Report Document Transition Report Local Phone Number Local Phone Number New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Goodwill Balance at June 30, 2022 Balance at March 31, 2023 Goodwill Notes payable Notes Payable Depreciation and amortization Cost, Depreciation and Amortization Adjustments to reconcile net earnings to cash flows provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Goodwill and Intangible Assets, net Goodwill and Intangible Assets Disclosure [Text Block] Provision for income taxes Income Tax Expense (Benefit) Deferred income taxes Deferred Income Tax Liabilities, Net Preferred stock, par value (in US$ per share) Preferred Stock, Par or Stated Value Per Share Twelve months ending June 30, 2027 Lessee, Operating Lease, Liability, to be Paid, Year Four Income Statement [Abstract] Income Statement [Abstract] Capital in Excess of Par Value Additional Paid-in Capital [Member] Document Fiscal Period Focus Document Fiscal Period Focus TOTAL COSTS OF REVENUES Cost of Goods and Services Sold Diluted weighted average shares outstanding (shares) Diluted, Weighted average shares (shares) Weighted Average Number of Shares Outstanding, Diluted Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Total corporate investments Investments Short-term marketable securities under reverse repurchase agreements Short-term Marketable Securities Under Reverse Repurchase Agreements Short-term Marketable Securities Under Reverse Repurchase Agreements 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. Common stock, $0.10 par value: authorized, 1,000.0 shares; issued, 638.7 shares at March 31, 2023 and June 30, 2022; outstanding, 413.5 and 416.1 shares at March 31, 2023 and June 30, 2022, respectively Common Stock, Value, Issued Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Short-term Debt [Line Items] Short-Term Debt [Line Items] Short-term lease cost Short-Term Lease, Cost Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized 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 Equivalents, Restricted Cash, and Restricted Cash Equivalents Allowance for doubtful accounts - trade receivables - Long-term Accounts Receivable, Allowance for Credit Loss, Noncurrent Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Current liabilities: Liabilities, Current [Abstract] Proceeds from the issuance of debt Proceeds from Issuance of Long-Term Debt Common stock, shares issued (in shares) Common Stock, Shares, Issued Term of credit agreement Line Of Credit Facility Term Of Credit Line Of Credit Facility Term Of Credit Short-term deferred revenues Contract with Customer, Liability, Current Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Report Line [Domain] Income Statement Location [Domain] 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 Total, Fair Market Value Debt Securities, Available-for-Sale, Unrealized Loss Position Amendment Flag Amendment Flag Useful life Finite-Lived Intangible Asset, Useful Life Net cash flows used in investing activities Net Cash Provided by (Used in) Investing Activities Operating lease cost Operating Lease, Cost Aggregate principal amount Debt Instrument, Face Amount Loss contingency, number of class action complaints filed Loss Contingency, New Claims Filed, Number Other comprehensive (loss)/income, net of tax Other comprehensive income Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Long-term marketable securities under reverse repurchase agreements Long-term Marketable Securities Under Reverse Repurchase Agreements Long-term Marketable Securities Under Reverse Repurchase Agreements Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Gross Unrealized  Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Entity Current Reporting Status Entity Current Reporting Status Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Capital expenditures Payments to Acquire Other Property, Plant, and Equipment Other assets Other Assets, Noncurrent Depreciation and amortization Depreciation, Depletion and Amortization Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] HCM HCM [Member] HCM [Member] Asset-Backed Auto Loan Receivables Asset Backed Auto Loan Receivables [Member] Securities collateralized by physical property Operating lease, contract term Lessee, Operating Lease, Term of Contract 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 Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Less: unamortized discount and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Non-current Non-current [Member] Non-current [Member] Net proceeds from stock purchase plan and stock-based compensation plans Net Proceeds from stock purchase plan and stock based compensation plans Proceeds from stock plans, stock options exercises, and payments related to tax withholding for share-based compensation. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Funds Held For Clients Funds Held For Clients [Member] Funds held for clients [Member] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Effect of exchange rate changes on cash, cash equivalents, restricted cash, and restricted cash equivalents Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Property, plant and equipment, net Property, Plant and Equipment, Net Cash paid for operating lease liabilities Operating Lease, Payments Payments of debt Repayments of Long-Term Debt 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. Schedule Of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Treasury stock - at cost: 225.2 and 222.7 shares at March 31, 2023 and June 30, 2022, respectively Treasury Stock, Value Other (Income)/Expense, Net Other Income and Other Expense Disclosure [Text Block] Federal Home Loan Banks Federal Home Loan Bank Certificates and Obligations (FHLB) [Member] Allowance for doubtful accounts - trade receivables - Current Accounts Receivable, Allowance for Credit Loss, Current Common stock, shares authorized (in shares) Common Stock, Shares Authorized Income taxes payable Accrued Income Taxes, Current Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Maximum Maximum [Member] Accumulated other comprehensive (loss)/ income Accumulated Other Comprehensive Income (Loss), Net of Tax Line of credit facility, fair value of amount outstanding Line of Credit Facility, Fair Value of Amount Outstanding Decrease in accounts payable Increase (Decrease) in Accounts Payable, Trade Cash and cash equivalents Money market securities, cash and other cash equivalents - amortized cost Cash and Cash Equivalents, at Carrying Value Total current assets Assets, Current Credit Facility Expiring In June 2026 Credit Facility Expiring In June Two Thousand Twenty Six [Member] Credit Facility Expiring In June Two Thousand Twenty Six [Member] Cash paid for income taxes, net of income tax refunds Income Taxes Paid, Net Recognition of revenue included in beginning of year contract liability Contract with Customer, Liability, Revenue Recognized Additions and other adjustments Goodwill, Other Increase (Decrease) Entity Small Business Entity Small Business Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Dividends declared (in US$ per share) Common Stock, Dividends, Per Share, Declared Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] REVENUES: Revenues [Abstract] Federal Farm Credit Banks Federal Farm Credit Banks [Member] Federal Farm Credit Banks [Member] Client funds held in grantor trust Client Funds Held in Grantor Trust Client Funds Held in Grantor Trust Software and software licenses Computer Software, Intangible Asset [Member] Title of 12(b) Security Title of 12(b) Security Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] TOTAL EXPENSES Costs and Expenses Debt Instrument [Line Items] Debt Instrument [Line Items] 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 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 Net lease obligations Operating Lease, Liability U.S. government agency securities U.S. government agency securities US Government Agencies Debt Securities [Member] Interim Financial Data by Segment Segment Reporting Disclosure [Text Block] Net amortization of premiums and accretion of discounts on available-for-sale securities Accretion (Amortization) of Discounts and Premiums, Investments Selling, general and administrative expenses Selling, General and Administrative Expenses [Member] Total current assets before funds held for clients Total Assets Before Funds Held Clients Total assets before funds held for clients Twelve months ending June 30, 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Two 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 Tax effect Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] U.S. Treasury securities US Treasury Securities [Member] Interest on funds held for clients client fund interest [Member] client fund interest [Member] Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost Additions to intangibles Payments to Acquire Intangible Assets Other comprehensive (loss)/income before reclassification adjustments OCI, before Reclassifications, before Tax, Attributable to Parent System development and programming costs System Development And Programming Costs [Member] System development and programming costs [Member] Accounts payable Accounts Payable, Current Other comprehensive (loss)/income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Increase in other assets Increase (Decrease) in Other Operating Assets Entity Filer Category Entity Filer Category Weighted average maturity (approximately in days) Commercial Paper Weight Average Maturity Reflects the calculated weighted average maturity of the Company's commercial paper Basic weighted average shares outstanding (shares) Basic, Weighted average shares (shares) Weighted Average Number of Shares Outstanding, Basic Total pretax stock-based compensation expense Share-Based Payment Arrangement, Expense Commitments and contingencies (Note 13) Commitments and Contingencies Security Exchange Name Security Exchange Name Gain on sale of assets Gain (Loss) on Disposition of Assets Preferred stock, $1.00 par value: authorized, 0.3 shares; issued, none Preferred Stock, Value, Issued Schedule of Long Term Debt Schedule of Debt [Table Text Block] TOTAL REVENUES Revenues Revenue from Contract with Customer, Excluding Assessed Tax Service cost – benefits earned during the period Defined Benefit Plan, Service Cost Less: current portion Debt, Current Cover [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Revenue Revenue from Contract with Customer [Text Block] Segment Reporting [Abstract] Segment Reporting [Abstract] Dividends declared Dividends, Stock Net amortization and deferral Defined Benefit Plan, Amortization of Gain (Loss) Total liabilities and stockholders’ equity Liabilities and Equity Costs of revenues: Cost of Goods and Services Sold [Abstract] Debt instrument, term Debt Instrument, Term Decrease/(Increase) in accounts receivable Increase (Decrease) in Accounts and Notes Receivable Net pension income Pension Cost (Reversal of Cost) Goodwill [Roll Forward] Goodwill [Roll Forward] Supranational Bonds Supranational Bonds [Member] Supranational Bonds Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] AOCI Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Acquisitions of businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Reclassification of pension liability adjustment to net earnings Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax Extension option term Debt Instrument, Extension Option Term Debt Instrument, Extension Option Term Current Fiscal Year End Date Current Fiscal Year End Date Total current liabilities before client funds obligations Total current liabilities before client funds obligations Total current liabilities before client funds obligations Less: Imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Short-term marketable securities Marketable Securities, Current Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Intangible assets, net Intangible assets, net Intangible Assets, Net (Excluding Goodwill) DILUTED EARNINGS PER SHARE (in US$ per share) Diluted, EPS (in US$ per share) Earnings Per Share, Diluted Proceeds from sale of property, plant, and equipment and other assets Proceeds from Sale of Property, Plant, and Equipment Current Current [Member] Current [Member] PEO zero-margin benefits pass-throughs PEO [Member] PEO [Member] Total current liabilities Liabilities, Current Twelve months ending June 30, 2025 Lessee, Operating Lease, Liability, to be Paid, Year Two Corporate Investments And Funds Held For Clients [Abstract] Corporate Investments And Funds Held For Clients [Abstract] Corporate Investments and Funds Held for Clients [Abstract] Other current assets Other Assets, Current Corporate bonds Corporate Debt Securities [Member] Canadian government obligations and Canadian government agency obligations Debt Security, Government, Non-US [Member] Schedule of Operating Lease Maturities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Entity Address, Address Line One Entity Address, Address Line One Contract liability, July 1, 2022 Contract liability, March 31, 2023 Contract with Customer, Liability Product and Service [Axis] Product and Service [Axis] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Interest expense Interest Expense Proceeds from the sales and maturities of corporate and client funds marketable securities Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Fixed Rate Credit Card Fixed Rate Credit Card [Member] Fixed Rate Credit Card [Member] Entity Tax Identification Number Entity Tax Identification Number Customer contracts and lists Customer Lists [Member] Schedule of Short-term Debt [Table] Schedule of Short-Term Debt [Table] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Three months ending June 30, 2023 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Weighted average interest rates Debt Instrument, Interest Rate During Period Settlement charges and special termination benefits Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment Net change in cash, cash equivalents, restricted cash, and restricted cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect 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 Available-for-sale securities, restricted Debt Securities, Available-for-Sale, Restricted Commercial paper program Commercial Paper [Member] Twelve months ending June 30, 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Five Entity Central Index Key Entity Central Index Key Notes due on 2025 an 2030 Notes due on 2025 an 2030 [Member] Notes due on 2025 an 2030 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. Interest income on corporate funds Investment Income, Interest Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Operating Lease Liabilities Operating lease liabilities [Table Text Block] Operating lease liabilities 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. City Area Code City Area Code Assets Assets [Abstract] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Other securities Other Other Debt Obligations [Member] Average outstanding balances Short-Term Debt, Average Outstanding Amount Client funds investments with original maturities Client Funds Investments Original Maturity Period Client funds investments, maturity period. Account Classification [Domain] Account Classification [Domain] [Domain] for Account Classification [Axis] Cash Flows from Financing Activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Fixed-rate 1.250% notes due September 1, 2030 Notes due on 2030 [Member] Notes due on 2030 Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Operating expenses Operating Expenses [Member] Operating expenses [Member] Other liabilities Other Liabilities, Noncurrent HRO, excluding PEO zero-margin benefits pass-throughs HRO [Member] HRO [Member] Impairment of assets Asset Impairment Charges Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Twelve months ending June 30, 2024 Finite-Lived Intangible Asset, Expected Amortization, Year One Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Operating lease ROU assets obtained in exchange for new operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability