Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013
Current:
Federal	$ 596	$ 259	$ 378
State	80	104	79
Foreign	369	499	442
Total	1,045	862	899
Deferred:
Federal	(66)	19	(4)
State	(11)	(3)	(4)
Foreign	(36)	(27)	(86)
Total	(113)	(11)	(94)
Income tax expense	$ 932	$ 851	$ 805