Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Current:
Federal	$ 398	$ 304	$ 596
State	82	71	80
Foreign	439	568	369
Total	919	943	1,045
Deferred:
Federal	(279)	(57)	(66)
State	(9)	(16)	(11)
Foreign	15	(7)	(36)
Total	(273)	(80)	(113)
Income tax expense	$ 646	$ 863	$ 932