Goodwill And Intangible Assets, Net (Changes In Goodwill) (Details) $ in Millions	3 Months Ended
	Sep. 30, 2016 USD ($)
Goodwill [Roll Forward]
Balance at June 30, 2016	$ 1,682.0
Additions and other adjustments, net	13.2
Currency translation adjustments	3.3
Balance at September 30, 2016	1,698.5
Employer Services
Goodwill [Roll Forward]
Balance at June 30, 2016	1,677.2
Additions and other adjustments, net	13.2
Currency translation adjustments	3.3
Balance at September 30, 2016	1,693.7
PEO Services
Goodwill [Roll Forward]
Balance at June 30, 2016	4.8
Additions and other adjustments, net	0.0
Currency translation adjustments	0.0
Balance at September 30, 2016	$ 4.8