Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Aug. 31, 2016	Aug. 31, 2015
Basic earnings per common share:
Net earnings allocable to common shares	[1]	$ 714	$ 691
Weighted-average common shares		265.0	282.0
Basic earnings per common share		$ 2.69	$ 2.45
Diluted earnings per common share:
Net earnings allocable to common shares	[1]	$ 714	$ 691
Weighted-average common shares		265.0	282.0
Dilutive effect of share-based awards		4.0	4.0
Weighted-average diluted shares		269.0	286.0
Diluted earnings per common share		$ 2.65	$ 2.42
Anti-dilutive options excluded from diluted earnings per common share		5.1	3.5

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