Business Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021
Segment Reporting Information [Line Items]
Revenue	$ 22,814	$ 23,474	$ 46,056	$ 45,477
Operating income (loss)	1,176	1,597	2,367	2,995
Operating Segments [Member] | FedEx Express Segment [Member]
Segment Reporting Information [Line Items]
Revenue	10,864	11,605	21,991	22,571
Operating income (loss)	341	949	515	1,516
Operating Segments [Member] | FedEx Ground Segment [Member]
Segment Reporting Information [Line Items]
Revenue	8,393	8,264	16,553	15,941
Operating income (loss)	598	481	1,292	1,152
Operating Segments [Member] | FedEx Freight Segment [Member]
Segment Reporting Information [Line Items]
Revenue	2,454	2,272	5,177	4,523
Operating income (loss)	440	334	1,091	724
Operating Segments [Member] | FedEx Services Segment [Member]
Segment Reporting Information [Line Items]
Revenue	68	77	138	112
Corporate, Other and Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	1,035	1,256	2,197	2,330
Operating income (loss)	$ (203)	$ (167)	$ (531)	$ (397)