Quarterly report pursuant to Section 13 or 15(d)

Basic and Diluted Earnings Per Share (Narrative) (Details)

v3.6.0.2
Basic and Diluted Earnings Per Share (Narrative) (Details)
shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Nov. 30, 2016
USD ($)
shares
Aug. 31, 2016
shares
Nov. 30, 2015
shares
Nov. 30, 2016
USD ($)
item
shares
Nov. 30, 2015
USD ($)
shares
Equity, Class of Treasury Stock [Line Items]          
Number of stock repurchase programs | item       2  
Common shares repurchased and retired | shares 2.9 0.0 0.0 2.9  
Common stock repurchased and retired $ 166.2     $ 166.2  
Authorized in May 2014 [Member]          
Equity, Class of Treasury Stock [Line Items]          
Expiration date       May 31, 2017  
Approved repurchase amount 350.0     $ 350.0  
Common stock repurchased and retired       $ 59.7  
Authorized in July 2016 [Member]          
Equity, Class of Treasury Stock [Line Items]          
Expiration date       May 31, 2019  
Approved repurchase amount $ 350.0     $ 350.0  
Common stock repurchased and retired       $ 106.5  
Common Stock [Member]          
Equity, Class of Treasury Stock [Line Items]          
Common stock issued in connection with exercise or vesting of stock-based awards | shares 0.1   0.4 1.4 1.1
Common Stock [Member] | Authorized in May 2014 [Member]          
Equity, Class of Treasury Stock [Line Items]          
Common shares repurchased and retired | shares         1.3
Common stock repurchased and retired         $ 62.9