General - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Feb. 28, 2023	Feb. 28, 2022	Feb. 28, 2023	Feb. 28, 2022
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 22,169	$ 23,641	$ 68,225	$ 69,118
Operating Segments [Member] | FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		10,345	11,304	32,336	33,875
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,165	2,275	6,718	6,694
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		478	479	1,477	1,435
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,346	1,422	3,886	3,960
Operating Segments [Member] | FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,989	4,176	12,081	12,089
Operating Segments [Member] | FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,566	2,991	8,286	8,937
Operating Segments [Member] | FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		698	697	2,116	2,072
Operating Segments [Member] | FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,264	3,688	10,402	11,009
Operating Segments [Member] | FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[1]	1,003	1,016	3,013	3,277
Operating Segments [Member] | FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		8,256	8,880	25,496	26,375
Operating Segments [Member] | FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		719	712	2,299	2,262
Operating Segments [Member] | FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		687	948	2,387	2,815
Operating Segments [Member] | FedEx Express Segment [Member] | International Economy Freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		358	378	1,123	1,230
Operating Segments [Member] | FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		47	40	126	134
Operating Segments [Member] | FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,811	2,078	5,935	6,441
Operating Segments [Member] | FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		278	346	905	1,059
Operating Segments [Member] | FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		8,658	8,800	25,211	24,741
Operating Segments [Member] | FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,186	2,253	7,363	6,776
Operating Segments [Member] | FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		87	65	225	177
Other and eliminations [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[2]	$ 893	$ 1,219	$ 3,090	$ 3,549

[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. (“FedEx Dataworks”) operating segments.