Corporate Investments And Funds Held For Clients (Available-For-Sale Securities That Have Been In An Unrealized Loss Position) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 40.3	$ 3.7
Fair market value of securities in unrealized loss position less than 12 months	4,242.9	982.1
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	8.3	34.4
Fair market value of securities in unrealized loss positions greater than 12 months	1,075.4	2,713.2
Total Gross Unrealized Losses	(48.6)	(38.1)
Total fair market value of securities in unrealized loss position	5,318.3	3,695.3
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	27.3	0.9
Fair market value of securities in unrealized loss position less than 12 months	2,403.5	313.8
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2.3	14.1
Fair market value of securities in unrealized loss positions greater than 12 months	228.1	1,026.0
Total Gross Unrealized Losses	(29.6)	(15.0)
Total fair market value of securities in unrealized loss position	2,631.6	1,339.8
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	7.2	0.3
Fair market value of securities in unrealized loss position less than 12 months	865.1	84.6
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2.6	11.4
Fair market value of securities in unrealized loss positions greater than 12 months	374.0	944.8
Total Gross Unrealized Losses	(9.8)	(11.7)
Total fair market value of securities in unrealized loss position	1,239.1	1,029.4
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3.2	0.7
Fair market value of securities in unrealized loss position less than 12 months	606.8	325.4
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2.9	6.2
Fair market value of securities in unrealized loss positions greater than 12 months	443.6	555.5
Total Gross Unrealized Losses	(6.1)	(6.9)
Total fair market value of securities in unrealized loss position	1,050.4	880.9
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.2	0.8
Fair market value of securities in unrealized loss position less than 12 months	85.8	127.2
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.0	0.0
Fair market value of securities in unrealized loss positions greater than 12 months	0.0	0.0
Total Gross Unrealized Losses	(0.2)	(0.8)
Total fair market value of securities in unrealized loss position	85.8	127.2
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.8	0.9
Fair market value of securities in unrealized loss position less than 12 months	101.5	75.2
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.0	1.6
Fair market value of securities in unrealized loss positions greater than 12 months	10.0	118.6
Total Gross Unrealized Losses	(0.8)	(2.5)
Total fair market value of securities in unrealized loss position	111.5	193.8
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1.2	0.1
Fair market value of securities in unrealized loss position less than 12 months	143.6	42.0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.2	0.4
Fair market value of securities in unrealized loss positions greater than 12 months	6.0	22.6
Total Gross Unrealized Losses	(1.4)	(0.5)
Total fair market value of securities in unrealized loss position	149.6	64.6
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.4	0.0
Fair market value of securities in unrealized loss position less than 12 months	36.6	13.9
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0.3	0.7
Fair market value of securities in unrealized loss positions greater than 12 months	13.7	45.7
Total Gross Unrealized Losses	(0.7)	(0.7)
Total fair market value of securities in unrealized loss position	$ 50.3	$ 59.6