Goodwill and Intangibles Assets, net (Changes In Goodwill) (Details) $ in Millions	9 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Roll Forward]
Balance at June 30, 2016	$ 1,682.0
Additions and other adjustments, net	79.5
Currency translation adjustments	(13.4)
Disposition of CHSA and COBRA businesses	(21.4)
Balance at March 31, 2017	1,726.7
Employer Services
Goodwill [Roll Forward]
Balance at June 30, 2016	1,677.2
Additions and other adjustments, net	79.5
Currency translation adjustments	(13.4)
Disposition of CHSA and COBRA businesses	(21.4)
Balance at March 31, 2017	1,721.9
PEO Services
Goodwill [Roll Forward]
Balance at June 30, 2016	4.8
Additions and other adjustments, net	0.0
Currency translation adjustments	0.0
Disposition of CHSA and COBRA businesses	0.0
Balance at March 31, 2017	$ 4.8