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	Sep. 30, 2012	Jun. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (1.2)	$ (2.3)
Fair market value less than 12 months	315.1	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	(1.2)	(2.7)
Total fair market value	315.1	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	0	(0.1)
Fair market value less than 12 months	3.1	43.6
Total gross unrealized losses	0	(0.1)
Total fair market value	3.1	43.6
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.3)	(1.1)
Fair market value less than 12 months	45.7	234.8
Unrealized losses greater than 12 months		(0.4)
Fair market value greater than 12 months		20.2
Total gross unrealized losses	(0.3)	(1.5)
Total fair market value	45.7	255.0
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	0	(0.3)
Fair market value less than 12 months	11.2	58.5
Unrealized losses greater than 12 months
Fair market value greater than 12 months
Total gross unrealized losses	0	(0.3)
Total fair market value	11.2	58.5
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.1)
Fair market value less than 12 months	13.1	13.6
Total gross unrealized losses	(0.1)	0
Total fair market value	13.1	13.6
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	0	(0.1)
Fair market value less than 12 months	9.9	22.8
Total gross unrealized losses	0	(0.1)
Total fair market value	9.9	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	(0.6)	(0.6)
Fair market value less than 12 months	217.0	209.4
Total gross unrealized losses	(0.6)	(0.6)
Total fair market value	217.0	209.4
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.2)	(0.1)
Fair market value less than 12 months	15.1	26.3
Total gross unrealized losses	(0.2)	(0.1)
Total fair market value	$ 15.1	$ 26.3