Financial Data By Segment (Financial Data By Strategic Business Unit Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Revenues	$ 2,839.6	$ 2,637.5
Earnings from Continuing Operations before Income Taxes	497.3	465.6
Employer Services [Member]
Segment Reporting Information [Line Items]
Revenues	1,968.0	1,818.9
Earnings from Continuing Operations before Income Taxes	522.6	455.1
PEO Services [Member]
Segment Reporting Information [Line Items]
Revenues	505.1	451.9
Earnings from Continuing Operations before Income Taxes	51.9	46.3
Dealer Services [Member]
Segment Reporting Information [Line Items]
Revenues	472.8	440.1
Earnings from Continuing Operations before Income Taxes	96.8	85.8
Other Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0.1	0.7
Earnings from Continuing Operations before Income Taxes	(67.6)	(47.5)
Client Fund Interest [Member]
Segment Reporting Information [Line Items]
Revenues	(106.4)	(74.1)
Earnings from Continuing Operations before Income Taxes	$ (106.4)	$ (74.1)