Financial Data By Segment And Geographic Area (Financial Data By Strategic Business Unit Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2010
Revenues from continuing operations	$ 2,636.6	$ 2,923.1	$ 2,583.0	$ 2,522.5	$ 2,507.1	$ 2,737.3	$ 2,405.7	$ 2,229.4	$ 10,665.2		$ 9,879.5		$ 8,927.7
Earnings from continuing operations before income taxes									2,122.1		1,932.7		1,863.2
Assets from continuing operations	30,815.5				34,238.3				30,815.5		34,238.3		26,862.2
Capital expenditures for continuing operations									146.2		184.8		90.2
Depreciation and amortization									323.3	[1]	318.2	[1]	309.2	[1]
Depreciation and amortization not related to services and products									63.3		64.8		70.6
Employer Services [Member]
Revenues from continuing operations									7,567.7		7,042.9		6,535.1
Earnings from continuing operations before income taxes									1,972.3		1,856.5		1,741.4
Assets from continuing operations	23,357.9				27,069.0				23,357.9		27,069.0		20,560.5
Capital expenditures for continuing operations									39.9		51.3		42.5
Depreciation and amortization									218.4		210.8		217.7
Professional Employee Organization Services Segment [Member]
Revenues from continuing operations									1,771.4		1,543.9		1,316.8
Earnings from continuing operations before income taxes									170.2		137.3		127.2
Assets from continuing operations	376.5				262.1				376.5		262.1		160.8
Capital expenditures for continuing operations									1.2		1.2		0.3
Depreciation and amortization									1.2		1.1		1.3
Dealer Services [Member]
Revenues from continuing operations									1,683.7		1,536.0		1,248.1
Earnings from continuing operations before income taxes									277.1		233.3		204.1
Assets from continuing operations	685.9				677.4				685.9		677.4		517.7
Capital expenditures for continuing operations									39.7		34.4		24.0
Depreciation and amortization									99.9		99.3		82.4
Other Reportable Segment [Member]
Revenues from continuing operations									5.5		12.8		18.5
Earnings from continuing operations before income taxes									(117.6)		(191.9)		(173.9)
Assets from continuing operations	6,395.2				6,229.8				6,395.2		6,229.8		5,623.2
Capital expenditures for continuing operations									65.4		97.9		23.4
Depreciation and amortization									128.4		123.9		117.8
Foreign Exchange Reconciling Item [Member]
Revenues from continuing operations									(55.9)		(43.2)		(54.1)
Earnings from continuing operations before income taxes									2.7		(6.5)		(8.9)
Client Fund Interest Reconciling Item [Member]
Revenues from continuing operations									(307.2)		(212.9)		(136.7)
Earnings from continuing operations before income taxes									(307.2)		(212.9)		(136.7)
Cost Of Capital Charge Reconciling Item [Member]
Earnings from continuing operations before income taxes									124.6		116.9		110.0
Depreciation and amortization									$ (124.6)		$ (116.9)		$ (110.0)

[1] Includes $63.3 million, $64.8 million, and $70.6 million for the years ended June 30, 2012, 2011 and 2010, respectively, of depreciation and amortization that does not relate to our services and products.