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	Dec. 31, 2012	Jun. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (4.8)	$ (2.3)
Fair market value less than 12 months	1,209.3	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	(4.8)	(2.7)
Total fair market value	1,209.3	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	(1.2)	(0.1)
Fair market value less than 12 months	439.3	43.6
Total gross unrealized losses	(1.2)	(0.1)
Total fair market value	439.3	43.6
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(1.3)	(1.1)
Fair market value less than 12 months	248.0	234.8
Unrealized losses greater than 12 months		(0.4)
Fair market value greater than 12 months		20.2
Total gross unrealized losses	(1.3)	(1.5)
Total fair market value	248.0	255.0
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.2)	(0.3)
Fair market value less than 12 months	35.5	58.5
Total gross unrealized losses	(0.2)	(0.3)
Total fair market value	35.5	58.5
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.2)
Fair market value less than 12 months	126.4	13.6
Total gross unrealized losses	(0.2)	0
Total fair market value	126.4	13.6
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.4)	(0.1)
Fair market value less than 12 months	45.9	22.8
Total gross unrealized losses	(0.4)	(0.1)
Total fair market value	45.9	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	(1.3)	(0.6)
Fair market value less than 12 months	280.9	209.4
Total gross unrealized losses	(1.3)	(0.6)
Total fair market value	280.9	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	33.3	26.3
Total gross unrealized losses	(0.2)	(0.1)
Total fair market value	$ 33.3	$ 26.3