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	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	$ (15.1)	$ (3.7)
Fair market value of securities in unrealized loss position less than 12 months	3,063.9	982.1
Unrealized losses greater than 12 months	(45.9)	(34.4)
Fair market value of securities in unrealized loss positions greater than 12 months	2,591.2	2,713.2
Total available for sale securities - Unrealized Loss	(61.0)	(38.1)
Total fair market value of securities in unrealized loss position	5,655.1	3,695.3
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(7.3)	(0.9)
Fair market value of securities in unrealized loss position less than 12 months	1,567.9	313.8
Unrealized losses greater than 12 months	(17.8)	(14.1)
Fair market value of securities in unrealized loss positions greater than 12 months	948.6	1,026.0
Total available for sale securities - Unrealized Loss	(25.1)	(15.0)
Total fair market value of securities in unrealized loss position	2,516.5	1,339.8
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(1.7)	(0.3)
Fair market value of securities in unrealized loss position less than 12 months	395.2	84.6
Unrealized losses greater than 12 months	(16.6)	(11.4)
Fair market value of securities in unrealized loss positions greater than 12 months	937.8	944.8
Total available for sale securities - Unrealized Loss	(18.3)	(11.7)
Total fair market value of securities in unrealized loss position	1,333.0	1,029.4
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(4.2)	(0.7)
Fair market value of securities in unrealized loss position less than 12 months	856.0	325.4
Unrealized losses greater than 12 months	(8.8)	(6.2)
Fair market value of securities in unrealized loss positions greater than 12 months	532.4	555.5
Total available for sale securities - Unrealized Loss	(13.0)	(6.9)
Total fair market value of securities in unrealized loss position	1,388.4	880.9
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)	(0.8)
Fair market value of securities in unrealized loss position less than 12 months	106.5	127.2
Unrealized losses greater than 12 months	0	0
Fair market value of securities in unrealized loss positions greater than 12 months	8.1	0
Total available for sale securities - Unrealized Loss	(0.6)	(0.8)
Total fair market value of securities in unrealized loss position	114.6	127.2
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(1.2)	(0.9)
Fair market value of securities in unrealized loss position less than 12 months	91.1	75.2
Unrealized losses greater than 12 months	(1.7)	(1.6)
Fair market value of securities in unrealized loss positions greater than 12 months	106.0	118.6
Total available for sale securities - Unrealized Loss	(2.9)	(2.5)
Total fair market value of securities in unrealized loss position	197.1	193.8
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	0	(0.1)
Fair market value of securities in unrealized loss position less than 12 months	28.1	42.0
Unrealized losses greater than 12 months	(0.2)	(0.4)
Fair market value of securities in unrealized loss positions greater than 12 months	13.3	22.6
Total available for sale securities - Unrealized Loss	(0.2)	(0.5)
Total fair market value of securities in unrealized loss position	41.4	64.6
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized losses less than 12 months	(0.1)	0
Fair market value of securities in unrealized loss position less than 12 months	19.1	13.9
Unrealized losses greater than 12 months	(0.8)	(0.7)
Fair market value of securities in unrealized loss positions greater than 12 months	45.0	45.7
Total available for sale securities - Unrealized Loss	(0.9)	(0.7)
Total fair market value of securities in unrealized loss position	$ 64.1	$ 59.6