Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2018	Feb. 28, 2018	May 31, 2018	May 31, 2017	May 31, 2016	May 31, 2015
Income Tax Contingency [Line Items]
Federal income tax rate			29.20%	35.00%	35.00%
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense		$ 2,010	$ 1,875
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, provisional income tax expense			$ 158
Income tax benefits attributable to employee stock-based compensation				$ 177	$ 281
Effective tax rate, change from prior period				(5.50%)
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, increase (decrease) in provisional income tax expense	$ 135
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, installments period			8 years
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, deferred tax asset, provisional income tax expense, gross			$ 158
Total gross unrecognized tax benefits, excluding related interest and penalties	698		698	$ 461	506	$ 438
Total gross unrecognized tax benefits, excluding related interest and penalties, amount which would affect the Company's effective tax rate if recognized in future periods	478		478
Increase (decrease) in liability for payment of interest and penalties	(14)		(14)	(38)	45
Accrued interest and penalties related to uncertain tax positions (excluding federal benefit)	157		157	171
Estimated decrease in total gross unrecognized tax benefits as a result of resolutions of global tax examinations and expiration of applicable statutes of limitations	163		163
Reinvestment of the cumulative undistributed earnings of certain foreign subsidiaries	12,200		$ 12,200
Tax holiday, expiration period			2021
Decrease in income tax expense related to tax holiday			$ 126	$ 187	$ 173
Decrease in income tax expense related to tax holiday per diluted share, (in dollars per share)			$ 0.08	$ 0.11	$ 0.10
Valuation allowance increase (decrease) related to tax benefits of certain subsidiaries with operating losses			$ 13	$ 30	$ 43
Foreign tax credit carry-forwards	0		0	$ 208
Available domestic and foreign loss carry-forwards	$ 289		289
Deferred income taxes and other liabilities
Income Tax Contingency [Line Items]
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense			$ 1,078