v2.4.0.6
Fair Value Measurements - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Nov. 30, 2012
Nov. 30, 2011
Nov. 30, 2012
Nov. 30, 2011
May 31, 2012
Fair Value, Measurement Inputs, Disclosure [Line Items]          
Available-for-sale securities with maturity dates within one year from purchase date $ 937   $ 937   $ 1,129
Available-for-sale securities with maturity dates over one year and less than five years from purchase date 297   297   311
Interest income related to cash and equivalents and short-term investments 6 7 14 15  
Fair value of long term debt $ 237   $ 237   $ 283