Annual report pursuant to Section 13 and 15(d)

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

v3.7.0.1
Basic and Diluted Earnings Per Share (Narrative) (Details) - USD ($)
shares in Millions, $ in Millions
12 Months Ended
May 31, 2017
May 31, 2016
May 31, 2015
Equity, Class of Treasury Stock [Line Items]      
Common stock repurchased and retired, shares 2.9    
Common stock repurchased and retired, values $ 166.2 $ 107.9 $ 182.4
Authorized in May 2014 [Member]      
Equity, Class of Treasury Stock [Line Items]      
Expiration date May 31, 2017    
Approved repurchase amount $ 350.0    
Common stock repurchased and retired, shares   2.2  
Common stock repurchased and retired, values $ 59.7 $ 107.9  
Authorized in July 2016 [Member]      
Equity, Class of Treasury Stock [Line Items]      
Expiration date May 31, 2019    
Approved repurchase amount $ 350.0    
Common stock repurchased and retired, values $ 106.5