Corporate Investments And Funds Held For Clients (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Dec. 31, 2015		Jun. 30, 2015
Schedule of Available-for-sale Securities [Line Items]
Earliest Corporate bond debt maturity date	January 2016
Latest corporate debt maturity date	December 2023
Earliest U.S. Treasury maturity date	January 2016
Latest U.S Treasury maturity date	August 2025
Available-for-sale securities - Fair Value	$ 20,285.1	[1]	$ 20,873.8	[2]
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 Fund Obligation repayment period	1 year
Client funds obligations	$ 30,237.7		24,650.5
Client funds investments with original maturities	ninety days or less
Percent of Level Two Investment Pricing Inputs Provided by Pricing Service	81.00%
Federal Home Loan Banks [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	$ 3,784.3
Federal Farm Credit Banks [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	886.3
Fixed Rate Credit Card [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	2,006.7
Asset-Backed Auto Loan Receivables [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	559.5
Rate Reduction [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	243.7
Supranational Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	223.0
Sovereign Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	263.0
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	92.1
Fair Value, Inputs, Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	0.0		0.0
Fair Value, Inputs, Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - Fair Value	$ 0.0		$ 0.0

[1] Included within available-for-sale securities are corporate investments with fair values of $47.9 million and funds held for clients with fair values of $20,237.2 million. All available-for-sale securities were included in Level 2 of the fair value hierarchy.

[2] Included within available-for-sale securities are corporate investments with fair values of $55.5 million and funds held for clients with fair values of $20,818.3 million. All available-for-sale securities were included in Level 2 of the fair value hierarchy.