Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	May 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate on continuing operations (percent)	11.40%	2.50%
Total gross unrecognized tax benefits, excluding related interest and penalties	$ 498		$ 461
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	247
Change in income tax penalties and interest accrued	9
Accrued interest and penalties related to uncertain tax positions (excluding federal benefit)	180		$ 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	$ 78