Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 560	$ 935	$ 1,305	$ 1,770
OTHER COMPREHENSIVE INCOME (LOSS):
Foreign currency translation adjustments, net of tax expense of $7 and $4 in 2019 and tax benefit of $7 and $31 in 2018	72	(31)	(11)	(193)
Amortization of prior service credit, net of tax benefit of $6 and $12 in 2019 and tax benefit of $7 and $14 in 2018	(20)	(23)	(41)	(46)
Other comprehensive income (loss)	52	(54)	(52)	(239)
COMPREHENSIVE INCOME	$ 612	$ 881	$ 1,253	$ 1,531