Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 935	$ 775	$ 1,770	$ 1,371
OTHER COMPREHENSIVE INCOME (LOSS):
Foreign currency translation adjustments, net of tax benefit of $7 and $31 in 2018 and tax benefit of $7 and tax expense of $18 in 2017	(31)	(90)	(193)	19
Amortization of prior service credit, net of tax benefit of $7 and $14 in 2018 and tax benefit of $11 and $22 in 2017	(23)	(19)	(46)	(38)
Other comprehensive income (loss)	(54)	(109)	(239)	(19)
COMPREHENSIVE INCOME	$ 881	$ 666	$ 1,531	$ 1,352