Corporate Investments And Funds Held For Clients (Corporate Investments And Funds Held For Clients) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Money market securities and other cash equivalents - Amortized Cost	$ 3,385.4		$ 2,773.7
Money market securities and other cash equivalents - Fair Value	3,385.4		2,773.7
Available-for-sale securities - Amortized Cost	20,007.6		19,832.1
Available-for-sale securities - Gross Unrealized Gains	290.6		362.5
Available-for-sale securities - Gross Unrealized Losses	(61.0)		(38.1)
Available-for-sale securities - Fair Value	20,237.2	[1]	20,156.5	[2]
Total corporate investments and funds held for clients - Amortized Cost	23,393.0		22,605.8
Total corporate investments and funds held for clients - Gross Unrealized Gains	290.6		362.5
Total corporate investments and funds held for clients - Gross Unrealized Losses	(61.0)		(38.1)
Total corporate investments and funds held for clients - Fair Value	23,622.6		22,930.2
Corporate Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	2,308.2		2,086.3
Funds Held For Clients [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	17,929.0		18,070.2
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	8,882.6		8,720.1
Available-for-sale securities - Gross Unrealized Gains	134.6		171.1
Available-for-sale securities - Gross Unrealized Losses	(25.1)		(15.0)
Available-for-sale securities - Fair Value	8,992.1	[1]	8,876.2	[2]
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	6,008.2		6,051.4
Available-for-sale securities - Gross Unrealized Gains	83.8		107.3
Available-for-sale securities - Gross Unrealized Losses	(18.3)		(11.7)
Available-for-sale securities - Fair Value	6,073.7	[1]	6,147.0	[2]
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	2,063.7		1,822.6
Available-for-sale securities - Gross Unrealized Gains	3.5		6.1
Available-for-sale securities - Gross Unrealized Losses	(13.0)		(6.9)
Available-for-sale securities - Fair Value	2,054.2	[1]	1,821.8	[2]
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	985.8		1,031.4
Available-for-sale securities - Gross Unrealized Gains	6.2		7.6
Available-for-sale securities - Gross Unrealized Losses	(0.6)		(0.8)
Available-for-sale securities - Fair Value	991.4	[1]	1,038.2	[2]
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	728.0		747.7
Available-for-sale securities - Gross Unrealized Gains	22.7		25.3
Available-for-sale securities - Gross Unrealized Losses	(2.9)		(2.5)
Available-for-sale securities - Fair Value	747.8	[1]	770.5	[2]
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	522.2		543.3
Available-for-sale securities - Gross Unrealized Gains	19.1		19.4
Available-for-sale securities - Gross Unrealized Losses	(0.2)		(0.5)
Available-for-sale securities - Fair Value	541.1	[1]	562.2	[2]
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	817.1		915.6
Available-for-sale securities - Gross Unrealized Gains	20.7		25.7
Available-for-sale securities - Gross Unrealized Losses	(0.9)		(0.7)
Available-for-sale securities - Fair Value	$ 836.9	[1]	$ 940.6	[2]

[1] Included within available-for-sale securities are corporate investments with fair values of $2,308.2 million and funds held for clients with fair values of $17,929.0 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 $2,086.3 million and funds held for clients with fair values of $18,070.2 million. All available-for-sale securities were included in Level 2.