Corporate Investments And Funds Held For Clients (Corporate Investments And Funds Held For Clients) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Jun. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Money market securities and other cash equivalents - Amortized Cost	$ 8,689.9		$ 5,431.2
Money market securities and other cash equivalents - Fair Value	8,689.9		5,431.2
Available-for-sale securities - Amortized Cost	19,047.3		18,551.3
Available-for-sale securities - Gross Unrealized Gains	338.3		418.5
Available-for-sale securities - Gross Unrealized Losses	(83.5)		(131.1)
Available-for-sale securities - Fair Value	19,302.1	[1]	18,838.7	[2]
Total corporate investments and funds held for clients - Amortized Cost	27,737.2		23,982.5
Total corporate investments and funds held for clients - Gross Unrealized Gains	338.3		418.5
Total corporate investments and funds held for clients - Gross Unrealized Losses	(83.5)		(131.1)
Total corporate investments and funds held for clients - Fair Value	27,992.0		24,269.9
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	8,062.0		7,868.3
Available-for-sale securities - Gross Unrealized Gains	150.2		166.2
Available-for-sale securities - Gross Unrealized Losses	(35.3)		(56.7)
Available-for-sale securities - Fair Value	8,176.9	[1]	7,977.8	[2]
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	6,039.8		5,983.7
Available-for-sale securities - Gross Unrealized Gains	112.8		152.6
Available-for-sale securities - Gross Unrealized Losses	(26.2)		(37.4)
Available-for-sale securities - Fair Value	6,126.4	[1]	6,098.9	[2]
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,682.3		1,374.1
Available-for-sale securities - Gross Unrealized Gains	3.9		5.3
Available-for-sale securities - Gross Unrealized Losses	(13.1)		(19.7)
Available-for-sale securities - Fair Value	1,673.1	[1]	1,359.7	[2]
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,027.4		998.2
Available-for-sale securities - Gross Unrealized Gains	7.9		10.7
Available-for-sale securities - Gross Unrealized Losses	(1.5)		(4.5)
Available-for-sale securities - Fair Value	1,033.8	[1]	1,004.4	[2]
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	685.3		695.7
Available-for-sale securities - Gross Unrealized Gains	21.4		20.7
Available-for-sale securities - Gross Unrealized Losses	(4.0)		(5.6)
Available-for-sale securities - Fair Value	702.7	[1]	710.8	[2]
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	517.7		536.9
Available-for-sale securities - Gross Unrealized Gains	16.6		16.7
Available-for-sale securities - Gross Unrealized Losses	(1.4)		(4.4)
Available-for-sale securities - Fair Value	532.9	[1]	549.2	[2]
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,032.8		1,094.4
Available-for-sale securities - Gross Unrealized Gains	25.5		46.3
Available-for-sale securities - Gross Unrealized Losses	(2.0)		(2.8)
Available-for-sale securities - Fair Value	1,056.3	[1]	1,137.9	[2]
Corporate Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	77.2		342.0
Funds Held For Clients [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	$ 19,224.9		$ 18,496.7

[1] Included within available-for-sale securities are corporate investments with fair values of $77.2 million and funds held for clients with fair values of $19,224.9 million. All available-for-sale securities were included in Level 2.

[2] 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.