Goodwill and Other Intangible Assets - Schedule of Goodwill (Details) - USD ($) $ in Millions		12 Months Ended
		May 31, 2022	May 31, 2021	May 31, 2020
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31				$ 8,414
Accumulated impairment charges		$ (2,042)		(2,042)
Goodwill		6,544	$ 6,992	6,372
Goodwill Roll Forward
Beginning Goodwill at May 31		6,992	6,372
Goodwill acquired	[1]		161
Other	[2]	(448)	459
Ending Goodwill at May 31		6,544	6,992
Accumulated impairment charges		(2,042)		(2,042)
Corporate, Other and Eliminations [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31				1,938
Accumulated impairment charges		(1,909)		(1,909)
Goodwill		53	57	29
Goodwill Roll Forward
Beginning Goodwill at May 31		57	29
Goodwill acquired	[1]		40
Other	[2]	(4)	(12)
Ending Goodwill at May 31		53	57
Accumulated impairment charges		(1,909)		(1,909)
FedEx Express Segment [Member] | Operating Segments [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31				4,869
Goodwill		4,925	5,358	4,869
Goodwill Roll Forward
Beginning Goodwill at May 31		5,358	4,869
Goodwill acquired	[1]		18
Other	[2]	(433)	471
Ending Goodwill at May 31		4,925	5,358
FedEx Ground Segment [Member] | Operating Segments [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31				840
Goodwill		932	943	840
Goodwill Roll Forward
Beginning Goodwill at May 31		943	840
Goodwill acquired	[1]		103
Other	[2]	(11)
Ending Goodwill at May 31		932	943
FedEx Freight Segment [Member] | Operating Segments [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31				767
Accumulated impairment charges		(133)		(133)
Goodwill		634	634	634
Goodwill Roll Forward
Beginning Goodwill at May 31		634	634
Ending Goodwill at May 31		634	$ 634
Accumulated impairment charges		$ (133)		$ (133)

[1] Goodwill acquired relates to the acquisition of ShopRunner. See Note 4 for more information.

[2] Primarily currency translation adjustments and purchase price allocation-related adjustments.