Corporate Investments And Funds Held For Clients (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Dec. 31, 2012	Jun. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	$ 18,456.3	$ 18,093.4
Earliest non-callable debt maturity date	January 2013
Latest non-callable debt maturity date	December 2022
Earliest corporate bond maturity date	January 2013
Latest corporate bond maturity date	December 2022
Length of shortest cash flow of residential mortgages used as collateral for companies mortgage backed securities (in years)	15 years
Length of longest cash flow of residential mortgages used as collateral for company's mortgage backed securities (in years)	30 years
Client funds obligations	23,064.7	20,856.2
Client funds investments with original maturities	90 days or less
Percentage of the available-for-sale securities were rated AAA or AA	84.00%
Federal Home Loan Banks [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	4,509.2	4,189.1
Federal Farm Credit Banks [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	1,303.7	1,134.1
Federal National Mortgage Association ("Fannie Mae") [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	289.3	428.6
Federal Home Loan Mortgage Corporation ("Freddie Mac") [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	129.1	384.6
Fixed Rate Credit Card [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	509.4	323.0
Rate Reduction [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	103.4	140.0
Asset-Backed Auto Loan Receivables [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	172.9	85.1
Sovereign Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	411.8	405.0
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	121.5	135.3
Supranational Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	438.2	427.7
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	$ 222.8	$ 282.3