Corporate Investments And Funds Held For Clients (Corporate Investments And Funds Held For Clients) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Jun. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Money market securities and other cash equivalents - Amortized Cost	$ 2,498.0		$ 5,431.2
Money market securities and other cash equivalents - Fair Value	2,498.0		5,431.2
Available-for-sale securities - Amortized Cost	18,379.1		18,551.3
Available-for-sale securities - Gross Unrealized Gains	403.0		418.5
Available-for-sale securities - Gross Unrealized Losses	(104.3)		(131.1)
Available-for-sale securities - Fair Value	18,677.8	[1]	18,838.7	[2]
Total corporate investments and funds held for clients - Amortized Cost	20,877.1		23,982.5
Total corporate investments and funds held for clients - Gross Unrealized Gains	403.0		418.5
Total corporate investments and funds held for clients - Gross Unrealized Losses	(104.3)		(131.1)
Total corporate investments and funds held for clients - Fair Value	21,175.8		24,269.9
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	7,719.6		7,868.3
Available-for-sale securities - Gross Unrealized Gains	166.4		166.2
Available-for-sale securities - Gross Unrealized Losses	(42.9)		(56.7)
Available-for-sale securities - Fair Value	7,843.1	[1]	7,977.8	[2]
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	5,983.3		5,983.7
Available-for-sale securities - Gross Unrealized Gains	142.5		152.6
Available-for-sale securities - Gross Unrealized Losses	(32.6)		(37.4)
Available-for-sale securities - Fair Value	6,093.2	[1]	6,098.9	[2]
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,351.8		1,374.1
Available-for-sale securities - Gross Unrealized Gains	4.7		5.3
Available-for-sale securities - Gross Unrealized Losses	(14.3)		(19.7)
Available-for-sale securities - Fair Value	1,342.2	[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	1,024.7		998.2
Available-for-sale securities - Gross Unrealized Gains	10.0		10.7
Available-for-sale securities - Gross Unrealized Losses	(3.6)		(4.5)
Available-for-sale securities - Fair Value	1,031.1	[1]	1,004.4	[2]
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	702.5		695.7
Available-for-sale securities - Gross Unrealized Gains	20.3		20.7
Available-for-sale securities - Gross Unrealized Losses	(5.1)		(5.6)
Available-for-sale securities - Fair Value	717.7	[1]	710.8	[2]
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	526.9		536.9
Available-for-sale securities - Gross Unrealized Gains	16.7		16.7
Available-for-sale securities - Gross Unrealized Losses	(3.6)		(4.4)
Available-for-sale securities - Fair Value	540.0	[1]	549.2	[2]
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,070.3		1,094.4
Available-for-sale securities - Gross Unrealized Gains	42.4		46.3
Available-for-sale securities - Gross Unrealized Losses	(2.2)		(2.8)
Available-for-sale securities - Fair Value	1,110.5	[1]	1,137.9	[2]
Corporate Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	3,090.9		342.0
Funds Held For Clients [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	$ 15,586.9		$ 18,496.7

[1] Included within available-for-sale securities are corporate investments with fair values of $3,090.9 million and funds held for clients with fair values of $15,586.9 million. At September 30, 2013, Level 1 securities included $8.0 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 $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.