Common Stock and Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	May 31, 2018 USD ($) $ / shares shares	May 31, 2017 USD ($) $ / shares shares	May 31, 2016 USD ($) $ / shares shares
Class A Convertible Common Stock
Common Stock and Share Based Compensation [Line Items]
Common stock, no par value | $ / shares	$ 0
Common stock, number of shares authorized (in shares) | shares	400,000,000
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
Class B Common Stock
Common Stock and Share Based Compensation [Line Items]
Common stock, no par value | $ / shares	$ 0
Common stock, number of shares authorized (in shares) | shares	2,400,000,000
Stock Incentive Plan | Class B Common Stock
Common Stock and Share Based Compensation [Line Items]
Shares available for grant (in shares) | shares	718,000,000
Stock options vesting period (in years)	4 years
Stock options expiration from the date of grant (in years)	10 years
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)	5 years 8 months 12 days
Weighted average remaining contractual life for options exercisable (in years)	4 years 4 months 24 days
Aggregate intrinsic value for options outstanding	$ 2,896
Aggregate intrinsic value for options exercisable	2,352
Total intrinsic value of options exercised	889	$ 594	$ 946
Stock options | Stock Incentive Plan
Common Stock and Share Based Compensation [Line Items]
Unrecognized compensation costs from stock options, net of estimated forfeitures	$ 195
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
Stock options | Stock Incentive Plan | Class B Common Stock
Common Stock and Share Based Compensation [Line Items]
Weighted average fair value per share of the options granted (in dollars per share) | $ / shares	$ 9.82	$ 9.38	$ 12.66
Employee Stock | Class B Common Stock
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) | shares	3,100,000	3,100,000	2,500,000
Restricted stock | Stock Incentive Plan
Common Stock and Share Based Compensation [Line Items]
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 4 months 24 days
Unrecognized compensation costs from restricted stock, net of estimated forfeitures	$ 104
Restricted stock | Stock Incentive Plan | Class B Common Stock
Common Stock and Share Based Compensation [Line Items]
Restricted and unrestricted stock granted to key employees under 1990 Plan, number of shares (in shares) | shares	1,800,000	400,000	1,000,000
Restricted stock granted to key employees under 1990 Plan, weighted average values per share (in dollars per shares) | $ / shares	$ 62.51	$ 57.59	$ 54.87
Restricted stock vested, fair value	$ 113	$ 60	$ 49