Business Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Segment Reporting Information [Line Items]
Revenue	$ 21,738	$ 22,169	$ 65,584	$ 68,225
Operating income (loss)	1,243	1,042	4,004	3,409
Operating Segments [Member] | FedEx Express Segment [Member]
Segment Reporting Information [Line Items]
Revenue	10,101	10,345	30,440	32,336
Operating income (loss)	233	119	575	634
Operating Segments [Member] | FedEx Ground Segment [Member]
Segment Reporting Information [Line Items]
Revenue	8,703	8,658	25,762	25,211
Operating income (loss)	942	844	2,945	2,136
Operating Segments [Member] | FedEx Freight Segment [Member]
Segment Reporting Information [Line Items]
Revenue	2,125	2,186	6,776	7,363
Operating income (loss)	340	386	1,308	1,477
Operating Segments [Member] | FedEx Services Segment [Member]
Segment Reporting Information [Line Items]
Revenue	64	87	201	225
Corporate, Other and Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	745	893	2,405	3,090
Operating income (loss)	$ (272)	$ (307)	$ (824)	$ (838)