Business Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Segment Reporting Information [Line Items]
Revenues	$ 17,010	$ 16,526	$ 51,886	$ 48,136
Operating income (loss)	911	858	3,150	2,944
FedEx Express Segment [Member]
Segment Reporting Information [Line Items]
Revenues	9,005	9,098	27,831	26,574
Operating income (loss)	370	317	1,357	1,238
FedEx Ground Segment [Member]
Segment Reporting Information [Line Items]
Revenues	5,261	4,828	15,202	13,598
Operating income (loss)	577	614	1,830	1,716
FedEx Freight Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,750	1,613	5,627	4,950
Operating income (loss)	97	49	421	322
FedEx Services Segment [Member]
Segment Reporting Information [Line Items]
Revenues	402	397	1,248	1,213
Corporate, Other and Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	592	590	1,978	1,801
Operating income (loss)	$ (133)	$ (122)	$ (458)	$ (332)