Financial Data By Segment And Geographic Area - Financial Data By Segment And Geographic Area - Depreciation and Amortization Included in Earnings before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total depreciation and amortization	$ 582.4	$ 561.9	$ 549.3
Other
Segment Reporting Information [Line Items]
Total depreciation and amortization	63.3	68.5	74.2
Employer Services | Operating Segments
Segment Reporting Information [Line Items]
Total depreciation and amortization	512.4	486.6	467.6
PEO Services | Operating Segments
Segment Reporting Information [Line Items]
Total depreciation and amortization	$ 6.7	$ 6.8	$ 7.5