General - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 17,010	$ 16,526	$ 51,886	$ 48,136
Operating Segments | FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		9,005	9,098	27,831	26,574
Operating Segments | FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,844	1,836	5,678	5,373
Operating Segments | FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		433	435	1,345	1,317
Operating Segments | FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,119	996	3,131	2,796
Operating Segments | FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,396	3,267	10,154	9,486
Operating Segments | FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,738	1,841	5,508	5,469
Operating Segments | FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		806	793	2,541	2,378
Operating Segments | FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,544	2,634	8,049	7,847
Operating Segments | FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[1]	1,078	1,140	3,412	3,424
Operating Segments | FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		7,018	7,041	21,615	20,757
Operating Segments | FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		772	739	2,294	2,040
Operating Segments | FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		477	532	1,574	1,527
Operating Segments | FedEx Express Segment [Member] | International Economy Freight
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		495	492	1,568	1,354
Operating Segments | FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		76	93	244	276
Operating Segments | FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,820	1,856	5,680	5,197
Operating Segments | FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		167	201	536	620
Operating Segments | FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		5,261	4,828	15,202	13,598
Operating Segments | FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,750	1,613	5,627	4,950
Operating Segments | FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		402	397	1,248	1,213
Other and eliminations [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[2]	$ 592	$ 590	$ 1,978	$ 1,801

[1] International domestic revenues relate to our intra-country operations.

[2] Includes the FedEx Logistics, Inc. (“FedEx Logistics” (formerly FedEx Trade Networks, Inc.)) operating segment.