Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans (Details 3)

v2.4.0.8
Stock-Based Compensation Plans (Details 3) (Employee Stock Option [Member], USD $)
In Millions, unless otherwise specified
12 Months Ended
May 31, 2013
May 31, 2012
May 31, 2011
Employee Stock Option [Member]
     
Stock options, other information      
Total intrinsic value of stock options exercised $ 7.8 $ 0.8 $ 1.9
Total grant-date fair value of stock options vested $ 3.0 $ 10.4 $ 20.0