General - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended
		Aug. 31, 2020	Aug. 31, 2019
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 19,321	$ 17,048
Operating Segments | FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		9,647	8,945
Operating Segments | FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,861	1,866
Operating Segments | FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		426	479
Operating Segments | FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,096	956
Operating Segments | FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,383	3,301
Operating Segments | FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,317	1,817
Operating Segments | FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		616	855
Operating Segments | FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,933	2,672
Operating Segments | FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[1]	1,088	1,076
Operating Segments | FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		7,404	7,049
Operating Segments | FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		833	695
Operating Segments | FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		653	464
Operating Segments | FedEx Express Segment [Member] | International Economy Freight
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		371	516
Operating Segments | FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		75	66
Operating Segments | FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,932	1,741
Operating Segments | FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		311	155
Operating Segments | FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		7,040	5,179
Operating Segments | FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,826	1,905
Operating Segments | FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		8	4
Other and eliminations [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[2]	$ 800	$ 1,015

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

[2] Includes the FedEx Logistics, Inc. (“FedEx Logistics”) and FedEx Office and Print Services, Inc. (“FedEx Office”) operating segments.