Business Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2017	Aug. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 15,297	$ 14,663
Operating Income	1,117	1,264
FedEx Express Segment [Member]
Segment Reporting Information [Line Items]
Revenues	8,652	8,460
Operating Income	433	610
FedEx Ground Segment [Member]
Segment Reporting Information [Line Items]
Revenues	4,639	4,290
Operating Income	626	610
FedEx Freight Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,752	1,658
Operating Income	176	135
FedEx Services Segment [Member]
Segment Reporting Information [Line Items]
Revenues	400	395
Eliminations, Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	(146)	(140)
Operating Income	$ (118)	$ (91)