Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2020	Aug. 31, 2019
Income Statement [Abstract]
REVENUE	$ 19,321	$ 17,048
OPERATING EXPENSES:
Salaries and employee benefits	6,852	6,087
Purchased transportation	4,977	4,028
Rentals and landing fees	936	920
Depreciation and amortization	926	879
Fuel	565	870
Maintenance and repairs	806	768
Other	2,669	2,519
OPERATING EXPENSES	17,731	16,071
OPERATING INCOME	1,590	977
OTHER INCOME (EXPENSE):
Interest, net	(184)	(137)
Other retirement plans income	201	168
Other, net	(1)	(12)
OTHER INCOME (EXPENSE)	16	19
INCOME BEFORE INCOME TAXES	1,606	996
PROVISION FOR INCOME TAXES	361	251
NET INCOME	$ 1,245	$ 745
EARNINGS PER COMMON SHARE:
Basic	$ 4.75	$ 2.86
Diluted	4.72	2.84
DIVIDENDS DECLARED PER COMMON SHARE	$ 1.30	$ 1.30