XML 84 R59.htm IDEA: XBRL DOCUMENT  v2.3.0.11
Stock Based Compensation (Details 1) (USD $)
In Millions, except Per Share data, unless otherwise specified
12 Months Ended
May 31, 2011
May 31, 2010
May 31, 2009
Share Based Compensation Allocation And Classification In Financial Statements Abstract      
Stock-based compensation expense $ 98 $ 101 $ 99
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology Abstract      
Stock-based compensation valuation method Black-Scholes    
Weighted-average Black-Scholes value $ 28.12 $ 20.47 $ 23.66
Intrinsic value of options exercised $ 80 $ 77 $ 7
Expected lives (in years) 5.9 5.7 5.5
Expected volatility 34.00% 32.00% 23.00%
Risk-free interest rate 2.36% 3.24% 3.28%
Dividend Yield 0.558% 0.742% 0.492%
Share Based Compensation Arrangement Stock Options Abstract      
Stock option vesting period range 1 to 4 years    
Percentage of options vesting ratably over four years 83.00%    
Restricted stock expiration period ratably over 4 years    
Maximum term of stock options 10 years