Goodwill and Other Intangible Assets - Schedule of Goodwill (Details) - USD ($) $ in Millions		12 Months Ended
		May 31, 2017	May 31, 2016	May 31, 2017	May 31, 2015
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31					$ 5,120
Accumulated impairment charges				$ (1,310)	(1,310)
GOODWILL		$ 7,154	$ 6,747	7,154	3,810
Goodwill Roll Forward
Beginning Goodwill at May 31		6,747	3,810
Goodwill acquired	[1]		2,964
Purchase adjustments and other	[2]	407	(27)
Ending Goodwill at May 31		7,154	6,747
Accumulated impairment charges				(1,310)	(1,310)
FedEx Express Segment [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31					1,677
GOODWILL		1,589	1,677	3,780	1,677
Goodwill Roll Forward
Beginning Goodwill at May 31		1,589	1,677
Purchase adjustments and other	[2]	2,191	(88)
Ending Goodwill at May 31		3,780	1,589
TNT Segment [Member]
Net Goodwill Detail [Abstract]
GOODWILL		2,964	2,964	1,180
Goodwill Roll Forward
Beginning Goodwill at May 31		2,964
Goodwill acquired	[1]		2,964
Purchase adjustments and other	[2]	(1,784)
Ending Goodwill at May 31		1,180	2,964
FedEx Ground Segment [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31					1,145
GOODWILL		1,211	1,145	1,211	1,145
Goodwill Roll Forward
Beginning Goodwill at May 31		1,211	1,145
Purchase adjustments and other	[2]		66
Ending Goodwill at May 31		1,211	1,211
FedEx Freight Segment [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31					773
Accumulated impairment charges				(133)	(133)
GOODWILL		635	640	635	640
Goodwill Roll Forward
Beginning Goodwill at May 31		635	640
Purchase adjustments and other	[2]		(5)
Ending Goodwill at May 31		635	635
Accumulated impairment charges				(133)	(133)
FedEx Services Segment [Member]
Net Goodwill Detail [Abstract]
Gross Goodwill at May 31					1,525
Accumulated impairment charges				(1,177)	(1,177)
GOODWILL		348	348	348	348
Goodwill Roll Forward
Beginning Goodwill at May 31		348	348
Ending Goodwill at May 31		$ 348	$ 348
Accumulated impairment charges				$ (1,177)	$ (1,177)

[1] Goodwill acquired relates to the acquisition of TNT Express in 2016. See Note 3 for related disclosures.

[2] Primarily purchase-related adjustments, currency translation adjustments, and acquired goodwill related to immaterial acquisitions. FY17 includes goodwill attributed to FedEx Express as part of the acquisition of TNT Express.