Goodwill And Intangible Assets, Net (Changes In Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Goodwill [Roll Forward]
Beginning balance	$ 2,243.5	$ 1,741.0
Additions and other adjustments	94.3	494.9
Currency translation adjustments	(14.8)	7.6
Ending balance	2,323.0	2,243.5
Employer Services [Member]
Goodwill [Roll Forward]
Beginning balance	2,238.7	1,736.2
Additions and other adjustments	94.3	494.9
Currency translation adjustments	(14.8)	7.6
Ending balance	2,318.2	2,238.7
PEO Services [Member]
Goodwill [Roll Forward]
Beginning balance	4.8	4.8
Additions and other adjustments	0.0	0.0
Currency translation adjustments	0.0	0.0
Ending balance	$ 4.8	$ 4.8