Stock Based Compensation - Additional Information (Detail) (Common Class B, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Aug. 31, 2014	Aug. 31, 2013
Stock Incentive Plan 1990
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	$ 285
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 8 months 12 days
Weighted average fair value per share of the options granted (in dollars per share)	$ 16.91	$ 14.85
Minimum term of market traded options for estimates of expected volatility (in years)	1 year
Employee Stock
Common Stock and Share Based Compensation [Line Items]
Employee stock purchase plans, payroll deductions (percent)	10.00%
Employee stock purchase plan offering period (in months)	6 months
Shares purchased, price as percentage of lower of the fair market value (percent)	85.00%
Employee Stock | Stock Incentive Plan 1990
Common Stock and Share Based Compensation [Line Items]
Accelerated stock option expense	$ 4	$ 4