Computation of Earnings Per Share - Schedule of Basic and Diluted Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016
Basic earnings per common share:
Net earnings allocable to common shares	[1]	$ 561	$ 506	$ 1,974	$ 1,888
Weighted-average common shares		266.0	272.0	266.0	278.0
Basic earnings per common share		$ 2.11	$ 1.86	$ 7.43	$ 6.79
Diluted earnings per common share:
Net earnings allocable to common shares	[1]	$ 561	$ 506	$ 1,974	$ 1,888
Weighted-average common shares		266.0	272.0	266.0	278.0
Dilutive effect of share-based awards		5.0	3.0	4.0	3.0
Weighted-average diluted shares		271.0	275.0	270.0	281.0
Diluted earnings per common share		$ 2.07	$ 1.84	$ 7.31	$ 6.71
Anti-dilutive options excluded from diluted earnings per common share		4.0	4.8	4.7	4.0

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