Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Aug. 31, 2015	Aug. 31, 2014
Basic earnings per common share:
Net earnings allocable to common shares	[1]	$ 691	$ 653
Weighted-average common shares		282.0	285.0
Basic earnings per common share		$ 2.45	$ 2.29
Diluted earnings per common share:
Net earnings allocable to common shares	[1]	$ 691	$ 653
Weighted-average common shares		282.0	285.0
Dilutive effect of share-based awards		4.0	4.0
Weighted-average diluted shares		286.0	289.0
Diluted earnings per common share		$ 2.42	$ 2.26
Anti-dilutive options excluded from diluted earnings per common share		3.5	2.1

[1] Net earnings available to participating securities were immaterial in all periods presented.