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, 2011	Jun. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (9.2)	$ (34.6)
Fair market value less than 12 months	888.4	2,517.0
Unrealized losses greater than 12 months	(3.9)
Fair market value greater than 12 months	93.3
Total available-for-sale securities - Gross Unrealized Losses	(13.1)	(34.6)
Total fair market value	981.7	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	(0.1)	(12.1)
Fair market value less than 12 months	108.7	1,049.0
Total available-for-sale securities - Gross Unrealized Losses	(0.1)	(12.1)
Total fair market value	108.7	1,049.0
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(7.0)	(16.9)
Fair market value less than 12 months	600.5	945.2
Unrealized losses greater than 12 months	(3.9)
Fair market value greater than 12 months	93.3
Total available-for-sale securities - Gross Unrealized Losses	(10.9)	(16.9)
Total fair market value	693.8	945.2
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair market value less than 12 months	4.8	0.5
Total fair market value	4.8	0.5
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair market value less than 12 months	18.8	17.3
Total fair market value	18.8	17.3
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months		(0.6)
Fair market value less than 12 months		35.0
Total available-for-sale securities - Gross Unrealized Losses		(0.6)
Total fair market value		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	(0.1)	(1.3)
Fair market value less than 12 months	13.6	227.7
Total available-for-sale securities - Gross Unrealized Losses	(0.1)	(1.3)
Total fair market value	13.6	227.7
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(2.0)	(3.7)
Fair market value less than 12 months	142.0	242.3
Total available-for-sale securities - Gross Unrealized Losses	(2.0)	(3.7)
Total fair market value	$ 142.0	$ 242.3