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, 2012	Jun. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (12.7)	$ (34.6)
Fair market value less than 12 months	1,338.1	2,517.0
Unrealized losses greater than 12 months	(0.4)
Fair market value greater than 12 months	20.2
Total gross unrealized losses	(13.1)	(34.6)
Total fair market value	1,358.3	2,517.0
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	(3.0)	(12.1)
Fair market value less than 12 months	209.3	1,049.0
Total gross unrealized losses	(3.0)	(12.1)
Total fair market value	209.3	1,049.0
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(7.2)	(16.9)
Fair market value less than 12 months	869.2	945.2
Unrealized losses greater than 12 months	(0.4)
Fair market value greater than 12 months	20.2
Total gross unrealized losses	(7.6)	(16.9)
Total fair market value	889.4	945.2
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	49.0	0.5
Total gross unrealized losses	(0.2)
Total fair market value	49.0	0.5
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair market value less than 12 months	19.2	17.3
Total gross unrealized losses
Total fair market value	19.2	17.3
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.4)	(0.6)
Fair market value less than 12 months	41.6	35.0
Total gross unrealized losses	(0.4)	(0.6)
Total fair market value	41.6	35.0
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.5)	(1.3)
Fair market value less than 12 months	80.3	227.7
Total gross unrealized losses	(0.5)	(1.3)
Total fair market value	80.3	227.7
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(1.4)	(3.7)
Fair market value less than 12 months	69.5	242.3
Total gross unrealized losses	(1.4)	(3.7)
Total fair market value	$ 69.5	$ 242.3