Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans (Details 3)

v3.2.0.727
Stock-Based Compensation Plans (Details 3) - Performance Stock Options [Member] - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 12 Months Ended
May. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Total intrinsic value of stock options exercised $ 2.7
Total grant-date fair value of stock options vested $ 2.6
Performance stock option activity [Roll Forward]  
Options outstanding, Beginning balance, Shares 2.8
Options outstanding, Beginning balance, Weighted-average exercise price per share $ 31.25
Options granted 0.0
Options granted, Weighted-average exercise price per share $ 0.00
Options exercised (0.1)
Options exercised, Weighted-average exercise price per share $ 30.17
Options forfeited 0.0
Options forfeited, Weighted-average exercise price per share $ 0.00
Options expired 0.0
Options expired, Weighted-average exercise price per share $ 0.00
Options outstanding, Ending balance, Shares 2.7
Options outstanding, Ending balance, Weighted-average exercise price per share $ 31.31
Options outstanding, Ending balance, Weighted-average remaining contractual term 6 years 4 months 24 days
Options outstanding, Ending balance, Aggregate intrinsic value $ 48.2
Options exercisable, Ending balance, Shares 0.5
Options exercisable, Ending balance, Weighted-average exercise price per share $ 31.20
Options exercisable, Ending balance, Weighted-average remaining contractual term 6 years 3 months 18 days
Options exercisable, Ending balance, Aggregate intrinsic value $ 8.6