General - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended
		Aug. 31, 2021	Aug. 31, 2020
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 22,003	$ 19,321
Operating Segments [Member] | FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		10,966	9,647
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,170	1,861
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		482	426
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,231	1,096
Operating Segments [Member] | FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,883	3,383
Operating Segments [Member] | FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,839	2,317
Operating Segments [Member] | FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		669	616
Operating Segments [Member] | FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,508	2,933
Operating Segments [Member] | FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[1]	1,114	1,088
Operating Segments [Member] | FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		8,505	7,404
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		775	833
Operating Segments [Member] | FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		873	653
Operating Segments [Member] | FedEx Express Segment [Member] | International Economy Freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		414	371
Operating Segments [Member] | FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		47	75
Operating Segments [Member] | FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,109	1,932
Operating Segments [Member] | FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		352	311
Operating Segments [Member] | FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		7,677	7,040
Operating Segments [Member] | FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,251	1,826
Operating Segments [Member] | FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		35	8
Other and eliminations [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[2]	$ 1,074	$ 800

[1] International domestic revenue relates to our international intra-country operations.

[2] Includes the FedEx Office and Print Services, Inc. (“FedEx Office”), FedEx Logistics, Inc. (“FedEx Logistics”), and FedEx Dataworks, Inc. (including ShopRunner, Inc.) (“FedEx Dataworks”) operating segments. The financial results of FedEx Dataworks are included in the period ended August 31, 2021.