Corporate Investments And Funds Held For Clients (Available-For-Sale Securities That Have Been In An Unrealized Loss Position) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Jun. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (7.7)	$ (2.3)
Fair market value less than 12 months	1,768.7	609.0
Unrealized losses greater than 12 months	0	(0.4)
Fair market value greater than 12 months	0	20.2
Total gross unrealized losses	(7.7)	(2.7)
Total fair market value	1,768.7	629.2
U.S. Treasury And Direct Obligations Of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(2.4)	(0.1)
Fair market value less than 12 months	505.2	43.6
Total gross unrealized losses	(2.4)	(0.1)
Total fair market value	505.2	43.6
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(3.0)	(1.1)
Fair market value less than 12 months	516.5	234.8
Unrealized losses greater than 12 months		(0.4)
Fair market value greater than 12 months		20.2
Total gross unrealized losses	(3.0)	(1.5)
Total fair market value	516.5	255.0
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.3)	(0.3)
Fair market value less than 12 months	45.1	58.5
Total gross unrealized losses	(0.3)	(0.3)
Total fair market value	45.1	58.5
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(1.1)	0
Fair market value less than 12 months	497.8	13.6
Total gross unrealized losses	(1.1)	0
Total fair market value	497.8	13.6
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.3)	(0.1)
Fair market value less than 12 months	47.6	22.8
Total gross unrealized losses	(0.3)	(0.1)
Total fair market value	47.6	22.8
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.3)	(0.6)
Fair market value less than 12 months	112.5	209.4
Total gross unrealized losses	(0.3)	(0.6)
Total fair market value	112.5	209.4
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.3)	(0.1)
Fair market value less than 12 months	44.0	26.3
Total gross unrealized losses	(0.3)	(0.1)
Total fair market value	$ 44.0	$ 26.3