Annual report pursuant to Section 13 and 15(d)

Income Taxes (Narrative) (Details)

v3.5.0.2
Income Taxes (Narrative) (Details) - USD ($)
$ in Millions
12 Months Ended
May 31, 2016
May 31, 2015
Income Tax Contingency [Line Items]    
Reserve for uncertain tax positions $ 54.2 $ 29.1
Impact of uncertain tax positions, if recognized, on effective income tax rate $ 54.2 $ 29.1
Federal [Member] | IRS [Member] | Earliest Tax Year [Member]    
Income Tax Contingency [Line Items]    
Fiscal year currently under audit 2012  
Fiscal years subject to potential audit 2015  
Federal [Member] | IRS [Member] | Latest Tax Year [Member]    
Income Tax Contingency [Line Items]    
Fiscal year currently under audit 2014  
Fiscal years subject to potential audit 2016