Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2017	Aug. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 596	$ 715
OTHER COMPREHENSIVE INCOME (LOSS):
Foreign currency translation adjustments, net of tax benefit of $25 in 2017 and tax expense of $4 in 2016	109	12
Amortization of prior service credit, net of tax benefit of $11 in 2017 and $11 in 2016	(19)	(19)
Other comprehensive income (loss)	90	(7)
COMPREHENSIVE INCOME	$ 686	$ 708