Financial Data By Segment (Financial Data By Strategic Business Unit Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Revenues from Continuing Operations	$ 3,031.7	$ 2,825.1	$ 8,266.8	$ 7,680.8
Earnings from Continuing Operations before Income Taxes	742.6	660.8	1,696.2	1,526.3
Employer Services [Member]
Segment Reporting Information [Line Items]
Revenues from Continuing Operations	2,474.7	2,350.9	6,743.7	6,396.1
Earnings from Continuing Operations before Income Taxes	934.3	842.3	2,145.9	1,961.6
PEO Services [Member]
Segment Reporting Information [Line Items]
Revenues from Continuing Operations	748.5	650.8	1,969.3	1,686.9
Earnings from Continuing Operations before Income Taxes	80.6	60.6	226.0	172.0
Other Segments [Member]
Segment Reporting Information [Line Items]
Revenues from Continuing Operations	(4.8)	(0.1)	(7.7)	0
Earnings from Continuing Operations before Income Taxes	(85.6)	(65.6)	(237.2)	(205.1)
Client Fund Interest [Member]
Segment Reporting Information [Line Items]
Revenues from Continuing Operations	(186.7)	(176.5)	(438.5)	(402.2)
Earnings from Continuing Operations before Income Taxes	$ (186.7)	$ (176.5)	$ (438.5)	$ (402.2)