Annual report pursuant to Section 13 and 15(d)

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

v3.5.0.2
Stock-Based Compensation Plans (Performance Share Activity) (Details) - Performance Awards [Member]
shares in Millions
12 Months Ended
May 31, 2016
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Nonvested, Beginning balance, Awards | shares 0.6
Granted, Awards | shares 0.1 [1]
Vested, Awards | shares (0.2)
Forfeited, Awards | shares
Nonvested, Ending balance, Awards | shares 0.5
Nonvested, Beginning balance, Weighted-average grant-date fair value per share | $ / shares $ 34.24
Granted, Weighted-average grant-date fair value per share | $ / shares 42.48 [1]
Vested, Weighted-average grant-date fair value per share | $ / shares 29.10
Forfeited, Weighted-average grant-date fair value per share | $ / shares 37.09
Nonvested, Ending balance, Weighted-average grant-date fair value per share | $ / shares $ 38.89
[1] Performance shares granted assuming achievement of performance goals at target. Actual amount of shares to be earned may differ from this amount.