Annual report pursuant to Section 13 and 15(d)

Funds Held for Clients and Corporate Investments (Details 2)

v2.4.0.8
Funds Held for Clients and Corporate Investments (Details 2) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 12 Months Ended
May 31, 2014
Security
Feb. 28, 2014
Nov. 30, 2013
Aug. 31, 2013
May 31, 2013
Security
Feb. 28, 2013
Nov. 30, 2012
Aug. 31, 2012
May 31, 2014
Security
May 31, 2013
Security
May 31, 2012
Funds Held for Clients and Corporate Investments [Abstract]                      
Gross realized gains                 $ 0.6 $ 0.9 $ 1.0
Gross realized losses                 0 0 0
Net realized gains 0.1 0.3 0 0.2 0 0.6 0.1 0.2 0.6 0.9 1.0
Maturity Date:                      
Due in one year or less, Amortized cost 392.0               392.0    
Due in one year or less, Fair value 394.3               394.3    
Due after one year through three years, Amortized cost 759.8               759.8    
Due after one year through three years, Fair value 776.0               776.0    
Due after three years through five years, Amortized cost 764.1               764.1    
Due after three years through five years, Fair value 774.3               774.3    
Due after five years, Amortized cost 1,441.0               1,441.0    
Due after five years, Fair value 1,446.8               1,446.8    
Total, Amortized cost 3,356.9               3,356.9    
Fair value 3,391.4       3,691.4       3,391.4 3,691.4  
Funds Held for Clients and Corporate Investments (Textual)                      
Net unrealized gain on available-for-sale securities 34.5       34.7       34.5 34.7  
Number of available-for-sale securities in an unrealized loss position 98       147       98 147  
Minimum maturity period for VRDNs primarily categorized as due after five years (in years)                 20 years    
Maximum maturity period for VRDNs primarily categorized as due after five years (in years)                 30 years    
Total, Gross unrealized losses $ 3.0       $ 5.7       $ 3.0 $ 5.7