Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans (Performance Stock Option Activity) (Details)

v3.5.0.2
Stock-Based Compensation Plans (Performance Stock Option Activity) (Details) - Performance Awards [Member]
$ / shares in Units, shares in Millions, $ in Millions
 12 Months Ended
May 31, 2016
USD ($)
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Outstanding, Beginning balance, Shares subject to options | shares 2.7
Granted, Shares subject to options | shares
Exercised, Shares subject to options | shares (0.1)
Forfeited, Shares subject to options | shares (0.1)
Expired, Shares subject to options | shares
Outstanding, Ending balance, Shares subject to options | shares 2.5
Exercisable, Shares subject to options | shares 0.4
Outstanding, Beginning balance, Weighted-average exercise price per share | $ / shares $ 31.31
Granted, Weighted-average exercise price per share | $ / shares
Exercised, Weighted-average exercise price per share | $ / shares 31.11
Forfeited, Weighted-average exercise price per share | $ / shares 29.85
Expired, Weighted-average exercise price per share | $ / shares
Outstanding, Ending balance, Weighted-average exercise price per share | $ / shares 31.36
Exercisable, Weighted-average exercise price per share | $ / shares $ 31.22
Outstanding, Weighted-average remaining contractual term (years) 5 years 4 months 24 days
Exercisable, Weighted-average remaining contractual term (years) 5 years 2 months 12 days
Outstanding, Aggregate intrinsic value | $ $ 57.9 [1]
Exercisable, Aggregate intrinsic value | $ $ 9.6 [1]
[1] Market price of the underlying stock as of May 31, 2016 less the exercise price.