Corporate Investments And Funds Held For Clients (Corporate Investments And Funds Held For Clients) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Jun. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Money market securities and other cash equivalents - Amortized Cost	$ 10,854.6		$ 5,431.2
Money market securities and other cash equivalents - Fair Value	10,854.6		5,431.2
Available-for-sale securities - Amortized Cost	18,696.7		18,551.3
Available-for-sale securities - Gross Unrealized Gains	341.4		418.5
Available-for-sale securities - Gross Unrealized Losses	(128.9)		(131.1)
Available-for-sale securities - Fair Value	18,909.2	[1]	18,838.7	[2]
Total corporate investments and funds held for clients - Amortized Cost	29,551.3		23,982.5
Total corporate investments and funds held for clients - Gross Unrealized Gains	341.4		418.5
Total corporate investments and funds held for clients - Gross Unrealized Losses	(128.9)		(131.1)
Total corporate investments and funds held for clients - Fair Value	29,763.8		24,269.9
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	7,776.7		7,868.3
Available-for-sale securities - Gross Unrealized Gains	143.5		166.2
Available-for-sale securities - Gross Unrealized Losses	(54.7)		(56.7)
Available-for-sale securities - Fair Value	7,865.5	[1]	7,977.8	[2]
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	6,049.5		5,983.7
Available-for-sale securities - Gross Unrealized Gains	123.3		152.6
Available-for-sale securities - Gross Unrealized Losses	(40.8)		(37.4)
Available-for-sale securities - Fair Value	6,132.0	[1]	6,098.9	[2]
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,555.0		1,374.1
Available-for-sale securities - Gross Unrealized Gains	3.7		5.3
Available-for-sale securities - Gross Unrealized Losses	(15.8)		(19.7)
Available-for-sale securities - Fair Value	1,542.9	[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	1,047.7		998.2
Available-for-sale securities - Gross Unrealized Gains	9.0		10.7
Available-for-sale securities - Gross Unrealized Losses	(3.4)		(4.5)
Available-for-sale securities - Fair Value	1,053.3	[1]	1,004.4	[2]
Canadian Provincial Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	711.3		695.7
Available-for-sale securities - Gross Unrealized Gains	18.7		20.7
Available-for-sale securities - Gross Unrealized Losses	(7.0)		(5.6)
Available-for-sale securities - Fair Value	723.0	[1]	710.8	[2]
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	529.3		536.9
Available-for-sale securities - Gross Unrealized Gains	15.4		16.7
Available-for-sale securities - Gross Unrealized Losses	(3.6)		(4.4)
Available-for-sale securities - Fair Value	541.1	[1]	549.2	[2]
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Amortized Cost	1,027.2		1,094.4
Available-for-sale securities - Gross Unrealized Gains	27.8		46.3
Available-for-sale securities - Gross Unrealized Losses	(3.6)		(2.8)
Available-for-sale securities - Fair Value	1,051.4	[1]	1,137.9	[2]
Corporate Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	82.4		342.0
Funds Held For Clients [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	$ 18,826.8		$ 18,496.7

[1] Included within available-for-sale securities are corporate investments with fair values of $82.4 million and funds held for clients with fair values of $18,826.8 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.