Common Stock and Stock Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Class A Convertible Common Stock
Common Stock and Share Based Compensation [Line Items]
Common Stock, number of shares authorized (in shares)	200,000,000
Common stock conversion	Each share of Class A Common Stock is convertible into one share of Class B Common Stock.
Common stock, Class A conversion ratio to Class B (in shares)	1
Common Class B
Common Stock and Share Based Compensation [Line Items]
Common Stock, number of shares authorized (in shares)	1,200,000,000
Stock Incentive Plan 1990 [Member] | Common Class B
Common Stock and Share Based Compensation [Line Items]
Shares available for grant (in shares)	326,000,000
Stock options vesting period (in years)	4 years
Stock options expiration from the date of grant (in years)	10 years
Unrecognized compensation costs from stock options, net of estimated forfeitures	$ 199
Unrecognized compensation costs from stock options, net of estimated forfeitures, to be recognized as operating overhead expense over a weighted average period (in years)	2 years 3 months 18 days
Weighted average fair value per share of the options granted (in dollars per share)	$ 12.71	$ 11.08	$ 8.84
Minimum term of market traded options for estimates of expected volatility (in years)	1 year
Weighted average remaining contractual life for options outstanding (in years)	6 years 3 months 18 days
Weighted average remaining contractual life for options exercisable (in years)	4 years 8 months 12 days
Aggregate intrinsic value for options outstanding	1,823
Aggregate intrinsic value for options exercisable	1,218
Total intrinsic value of options exercised	293	453	267
Restricted Stock | Stock Incentive Plan 1990 [Member] | Common Class B
Common Stock and Share Based Compensation [Line Items]
Restricted and unrestricted stock granted to key employees under 1990 Plan, number of shares (in shares)	1,600,000	700,000	400,000
Restricted stock granted to key employees under 1990 Plan, weighted average values per share (in dollars per shares)	$ 46.86	$ 49.49	$ 35.11
Restricted stock vested, fair value	$ 25	$ 22	$ 15
Employee Stock [Member] | Common Class B
Common Stock and Share Based Compensation [Line Items]
Employee stock purchase plans, payroll deductions	10.00%
Employee stock purchase plan offering period	6 months
Shares purchased, price as percentage of lower of the fair market value	85.00%
Purchase of shares by employee (in shares)	1,600,000	1,700,000	1,600,000