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, 2015	Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (6.2)	$ (34.4)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,873.5	3,695.3
Fair market value of securities in unrealized loss position less than 12 months	817.1	982.1
Fair market value of securities in unrealized loss positions greater than 12 months	1,056.4	2,713.2
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(8.9)	(38.1)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2.7)	(3.7)
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(1.1)	(14.1)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	574.1	1,339.8
Fair market value of securities in unrealized loss position less than 12 months	349.2	313.8
Fair market value of securities in unrealized loss positions greater than 12 months	224.9	1,026.0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(2.6)	(15.0)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1.5)	(0.9)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(2.4)	(11.4)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	466.7	1,029.4
Fair market value of securities in unrealized loss position less than 12 months	67.5	84.6
Fair market value of securities in unrealized loss positions greater than 12 months	399.2	944.8
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(2.8)	(11.7)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.4)	(0.3)
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(2.4)	(6.2)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	661.5	880.9
Fair market value of securities in unrealized loss position less than 12 months	256.3	325.4
Fair market value of securities in unrealized loss positions greater than 12 months	405.2	555.5
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(2.8)	(6.9)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.4)	(0.7)
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	44.0	127.2
Fair market value of securities in unrealized loss position less than 12 months	44.0	127.2
Fair market value of securities in unrealized loss positions greater than 12 months	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(0.1)	(0.8)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.1)	(0.8)
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	0	(1.6)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	51.1	193.8
Fair market value of securities in unrealized loss position less than 12 months	41.1	75.2
Fair market value of securities in unrealized loss positions greater than 12 months	10.0	118.6
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(0.1)	(2.5)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.1)	(0.9)
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.1)	(0.4)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	56.1	64.6
Fair market value of securities in unrealized loss position less than 12 months	53.0	42.0
Fair market value of securities in unrealized loss positions greater than 12 months	3.1	22.6
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(0.3)	(0.5)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.2)	(0.1)
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.2)	(0.7)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	20.0	59.6
Fair market value of securities in unrealized loss position less than 12 months	6.0	13.9
Fair market value of securities in unrealized loss positions greater than 12 months	14.0	45.7
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(0.2)	(0.7)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0	$ 0