Corporate Investments And Funds Held For Clients (Corporate Investments And Funds Held For Clients) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Jun. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Money market securities and other cash equivalents - Amortized Cost	$ 5,431.2		$ 5,111.1
Money market securities and other cash equivalents - Fair Value	5,431.2		5,111.1
Total available-for-sale securities - Amortized Cost	18,551.3		17,382.9
Total available-for-sale securities - Gross Unrealized Gains	418.5		713.2
Total available-for-sale securities - Gross Unrealized Losses	(131.1)		(2.7)
Total available-for-sale securities - Fair Value	18,838.7	[1]	18,093.4	[2]
Total corporate investments and funds held for clients - Amortized Cost	23,982.5		22,494.0
Total corporate investments and funds held for clients - Gross Unrealized Gains	418.5		713.2
Total corporate investments and funds held for clients - Gross Unrealized Losses	(131.1)		(2.7)
Total corporate investments and funds held for clients - Fair Value	24,269.9		23,204.5
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	7,868.3		7,097.2
Total available-for-sale securities - Gross Unrealized Gains	166.2		272.3
Total available-for-sale securities - Gross Unrealized Losses	(56.7)		(1.5)
Total available-for-sale securities - Fair Value	7,977.8	[1]	7,368.0	[2]
U.S. Treasury And Direct Obligations Of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	5,983.7		6,413.8
Total available-for-sale securities - Gross Unrealized Gains	152.6		260.9
Total available-for-sale securities - Gross Unrealized Losses	(37.4)		(0.1)
Total available-for-sale securities - Fair Value	6,098.9	[1]	6,674.6	[2]
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	1,374.1		533.9
Total available-for-sale securities - Gross Unrealized Gains	5.3		14.5
Total available-for-sale securities - Gross Unrealized Losses	(19.7)		0
Total available-for-sale securities - Fair Value	1,359.7	[1]	548.4	[2]
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	998.2		994.2
Total available-for-sale securities - Gross Unrealized Gains	10.7		23.4
Total available-for-sale securities - Gross Unrealized Losses	(4.5)		(0.6)
Total available-for-sale securities - Fair Value	1,004.4	[1]	1,017.0	[2]
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	695.7		620.8
Total available-for-sale securities - Gross Unrealized Gains	20.7		35.4
Total available-for-sale securities - Gross Unrealized Losses	(5.6)		(0.3)
Total available-for-sale securities - Fair Value	710.8	[1]	655.9	[2]
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	536.9		522.0
Total available-for-sale securities - Gross Unrealized Gains	16.7		31.0
Total available-for-sale securities - Gross Unrealized Losses	(4.4)		(0.1)
Total available-for-sale securities - Fair Value	549.2	[1]	552.9	[2]
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Amortized Cost	1,094.4		1,201.0
Total available-for-sale securities - Gross Unrealized Gains	46.3		75.7
Total available-for-sale securities - Gross Unrealized Losses	(2.8)		(0.1)
Total available-for-sale securities - Fair Value	1,137.9	[1]	1,276.6	[2]
Corporate Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Fair Value	342.0		117.3
Funds Held For Clients [Member]
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities - Fair Value	$ 18,496.7		$ 17,976.1

[1] Included within available-for-sale securities are corporate investments with fair values of $342.0 million and funds held for clients with fair values of $18,496.7 million. At June 30, 2013, Level 1 securities included $9.5 million of corporate investments classified within "Other securities," all remaining available-for-sale securities were included in Level 2.

[2] Included within available-for-sale securities are corporate investments with fair values of $117.3 million and funds held for clients with fair values of $17,976.1 million. At June 30, 2012, Level 1 securities included $20.6 million of corporate investments classified within "Other securities," all remaining available-for-sale securities were included in Level 2.