Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 562	$ 507	$ 1,977	$ 1,890
OTHER COMPREHENSIVE INCOME (LOSS):
Foreign currency translation adjustments, net of tax of $3, $11, $19 and $28	110	(99)	(108)	(270)
Amortization of prior service credit, net of tax of $12, $12, $34 and $30	(19)	(19)	(57)	(61)
Other comprehensive loss	91	(118)	(165)	(331)
COMPREHENSIVE INCOME	$ 653	$ 389	$ 1,812	$ 1,559