Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021
Income Statement [Abstract]
REVENUE	$ 22,814	$ 23,474	$ 46,056	$ 45,477
OPERATING EXPENSES:
Salaries and employee benefits	7,792	8,135	15,651	15,911
Purchased transportation	5,665	6,241	11,432	11,900
Rentals and landing fees	1,195	1,177	2,354	2,310
Depreciation and amortization	1,046	995	2,070	1,966
Fuel	1,593	1,145	3,415	2,154
Maintenance and repairs	882	839	1,786	1,708
Business realignment and optimization costs	36	44	74	111
Other	3,429	3,301	6,907	6,422
OPERATING EXPENSES	21,638	21,877	43,689	42,482
OPERATING INCOME	1,176	1,597	2,367	2,995
OTHER (EXPENSE) INCOME:
Interest, net	(127)	(155)	(269)	(315)
Other retirement plans income	101	(47)	202	169
Other, net	(91)	(15)	(87)	(12)
OTHER (EXPENSE) INCOME	(117)	(217)	(154)	(158)
INCOME BEFORE INCOME TAXES	1,059	1,380	2,213	2,837
PROVISION FOR INCOME TAXES	271	336	550	681
NET INCOME	$ 788	$ 1,044	$ 1,663	$ 2,156
EARNINGS PER COMMON SHARE:
Basic	$ 3.08	$ 3.94	$ 6.46	$ 8.11
Diluted	3.07	3.88	6.41	7.97
DIVIDENDS DECLARED PER COMMON SHARE	$ 1.15	$ 0.75	$ 3.45	$ 2.25