Business Segments and Disaggregated Revenue - Schedule of Geographical Information (Details) - USD ($) $ in Millions		12 Months Ended
		May 31, 2023	May 31, 2022	May 31, 2021
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	$ 90,155	$ 93,512	$ 83,959
Assets Noncurrent	[1]	68,533	65,629	62,197
U.S. [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	64,890	64,941	58,792
Assets Noncurrent	[1]	56,449	53,311	49,407
International [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	25,265	28,571	25,167
Assets Noncurrent	[1]	12,084	12,318	12,790
FedEx Express Segment [Member] | International [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	23,090	25,564	23,085
FedEx Ground Segment [Member] | International [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	860	857	735
FedEx Freight Segment [Member] | International [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	264	235	190
FedEx Services Segment [Member] | International [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	1	1	1
Other international revenue [Member] | International [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	[1]	$ 1,050	$ 1,914	$ 1,156

[1] International revenue includes shipments that either originate in or are destined to locations outside the United States, which could include U.S. payors. Noncurrent assets include property and equipment, operating lease right-of-use assets, goodwill, and other long-term assets. Our flight equipment is registered in the U.S. and is included as U.S. assets; however, many of our aircraft operate internationally.