Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Income Statement [Abstract]
REVENUE	$ 23,641	$ 21,510	$ 69,118	$ 61,394
OPERATING EXPENSES:
Salaries and employee benefits	8,244	8,010	24,155	22,305
Purchased transportation	6,272	5,660	18,172	16,044
Rentals and landing fees	1,225	1,131	3,535	3,073
Depreciation and amortization	986	956	2,952	2,818
Fuel	1,201	756	3,355	1,946
Maintenance and repairs	822	822	2,530	2,443
Business realignment costs	107	10	218	10
Other	3,458	3,160	9,880	8,695
OPERATING EXPENSES	22,315	20,505	64,797	57,334
OPERATING INCOME	1,326	1,005	4,321	4,060
OTHER (EXPENSE) INCOME:
Interest, net	(163)	(187)	(478)	(555)
Other retirement plans income	211	202	380	553
Other, net	1	29	(11)	3
OTHER (EXPENSE) INCOME	49	44	(109)	1
INCOME BEFORE INCOME TAXES	1,375	1,049	4,212	4,061
PROVISION FOR INCOME TAXES	263	157	944	698
NET INCOME	$ 1,112	$ 892	$ 3,268	$ 3,363
EARNINGS PER COMMON SHARE:
Basic	$ 4.26	$ 3.36	$ 12.36	$ 12.75
Diluted	4.20	3.30	12.17	12.55
DIVIDENDS DECLARED PER COMMON SHARE	$ 0.75	$ 0.65	$ 3.00	$ 2.60