Goodwill and Intangible Assets, net - Changes In Goodwill (Details) $ in Millions	6 Months Ended
	Dec. 31, 2022 USD ($)
Goodwill [Roll Forward]
Balance at June 30, 2022	$ 2,300.5
Additions and other adjustments	11.6
Currency translation adjustments	2.9
Balance at December 31, 2022	2,315.0
Employer Services
Goodwill [Roll Forward]
Balance at June 30, 2022	2,295.7
Additions and other adjustments	11.6
Currency translation adjustments	2.9
Balance at December 31, 2022	2,310.2
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 December 31, 2022	$ 4.8