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. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Basic earnings per common share:
Net earnings allocable to common shares	[1]	$ 314	$ 738	$ 1,617	$ 2,506
Weighted-average common shares		261.0	261.0	261.0	262.0
Basic earnings per common share		$ 1.21	$ 2.83	$ 6.21	$ 9.55
Diluted earnings per common share:
Net earnings allocable to common shares	[1]	$ 314	$ 738	$ 1,617	$ 2,506
Weighted-average common shares		261.0	261.0	261.0	262.0
Dilutive effect of share-based awards		1.0	2.0	1.0	4.0
Weighted-average diluted shares		262.0	263.0	262.0	266.0
Diluted earnings per common share		$ 1.20	$ 2.80	$ 6.17	$ 9.41
Anti-dilutive options excluded from diluted earnings per common share		11.7	7.2	11.2	5.0

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