Service Revenue (Summary of PEO Pass-Through Costs Netted in Revenue) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Nov. 30, 2025 |
Nov. 30, 2024 |
Nov. 30, 2025 |
Nov. 30, 2024 |
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| Revenue from Contract with Customer [Abstract] | ||||
| Payroll wages and payroll taxes | $ 7,694.6 | $ 7,172.0 | $ 15,050.7 | $ 14,053.6 |
| State unemployment insurance (included in payroll wages and payroll taxes) | 22.4 | 23.4 | 46.1 | 46.4 |
| Guaranteed cost benefit plans | $ 177.9 | $ 167.5 | $ 353.4 | $ 333.3 |
| X | ||||||||||
- Definition Direct Pass Through Cost Guaranteed Cost Benefit Plans No definition available.
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| X | ||||||||||
- Definition Direct Pass Through Cost Payroll Wages And Taxes Including Federal And State Unemployment Insurance No definition available.
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| X | ||||||||||
- Definition Direct Pass Through Cost State Unemployment Insurance No definition available.
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| X | ||||||||||
- References No definition available.
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