Goodwill and Intangible Assets, net - Changes In Goodwill (Details) $ in Millions	9 Months Ended
	Mar. 31, 2023 USD ($)
Goodwill [Roll Forward]
Balance at June 30, 2022	$ 2,300.5
Additions and other adjustments	26.2
Currency translation adjustments	9.0
Balance at March 31, 2023	2,335.7
Employer Services
Goodwill [Roll Forward]
Balance at June 30, 2022	2,295.7
Additions and other adjustments	26.2
Currency translation adjustments	9.0
Balance at March 31, 2023	2,330.9
PEO Services
Goodwill [Roll Forward]
Balance at June 30, 2022	4.8
Additions and other adjustments	0.0
Currency translation adjustments	0.0
Balance at March 31, 2023	$ 4.8