v3.3.1.900
Fair Value Measurements - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended
Nov. 30, 2015
Nov. 30, 2014
Nov. 30, 2015
Nov. 30, 2014
May. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]          
Available-for-sale securities with maturity dates within one year from purchase date $ 2,020,000,000   $ 2,020,000,000    
Available-for-sale securities with maturity dates over one year and less than five years from purchase date 245,000,000   245,000,000    
Interest income 2,000,000 $ 2,000,000 4,000,000 $ 3,000,000  
Fair value of long term debt 2,020,000,000   2,020,000,000   $ 1,160,000,000
Fair value transfers between fair value hierarchy levels     0    
Assets, fair value disclosure, nonrecurring 0   0   0
Liabilities, fair value disclosure, nonrecurring 0   0   0
Prepaid Expenses and Other Current Assets          
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]          
Outstanding receivables 150,000,000   150,000,000   150,000,000
Foreign exchange forwards and options          
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]          
Derivative liability, fair value of collateral 0   0    
Foreign exchange forwards and options | Cash and Cash Equivalents          
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]          
Derivative liability, fair value of collateral         $ 0
Interest rate swap          
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]          
Derivative liability, fair value of collateral $ 0   $ 0