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, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 3,320.0	$ 3,109.3	$ 9,132.7	$ 8,484.8
Earnings from Continuing Operations before Income Taxes	769.8	723.3	1,825.2	1,715.1
Employer Services [Member]
Segment Reporting Information [Line Items]
Revenues	2,350.9	2,223.2	6,396.1	5,950.4
Earnings from Continuing Operations before Income Taxes	840.5	780.2	1,956.0	1,747.3
PEO Services [Member]
Segment Reporting Information [Line Items]
Revenues	650.8	565.5	1,686.9	1,483.1
Earnings from Continuing Operations before Income Taxes	60.5	54.6	171.9	150.9
Dealer Services [Member]
Segment Reporting Information [Line Items]
Revenues	494.9	463.3	1,452.0	1,355.9
Earnings from Continuing Operations before Income Taxes	113.5	98.0	315.0	280.1
Other Segments [Member]
Segment Reporting Information [Line Items]
Revenues	(0.1)	0.2	(0.1)	1.5
Earnings from Continuing Operations before Income Taxes	(68.2)	(66.6)	(215.5)	(157.1)
Client Fund Interest [Member]
Segment Reporting Information [Line Items]
Revenues	(176.5)	(142.9)	(402.2)	(306.1)
Earnings from Continuing Operations before Income Taxes	$ (176.5)	$ (142.9)	$ (402.2)	$ (306.1)