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		6 Months Ended
		Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Basic earnings per common share:
Net earnings allocable to common shares	[1]	$ 559	$ 933	$ 1,303	$ 1,768
Weighted-average common shares		261.0	262.0	261.0	263.0
Basic earnings per common share		$ 2.15	$ 3.56	$ 5.00	$ 6.71
Diluted earnings per common share:
Net earnings allocable to common shares	[1]	$ 559	$ 933	$ 1,303	$ 1,768
Weighted-average common shares		261.0	262.0	261.0	263.0
Dilutive effect of share-based awards		1.0	4.0	1.0	5.0
Weighted-average diluted shares		262.0	266.0	262.0	268.0
Diluted earnings per common share		$ 2.13	$ 3.51	$ 4.97	$ 6.60
Anti-dilutive options excluded from diluted earnings per common share		11.2	4.0	11.0	3.8

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