Business Segment Information - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended																12 Months Ended
		May 31, 2017		Feb. 28, 2017	[1]	Nov. 30, 2016	[1]	Aug. 31, 2016	[1]	May 31, 2016		Feb. 29, 2016	[2]	Nov. 30, 2015	[2]	Aug. 31, 2015	[2]	May 31, 2017	May 31, 2016	May 31, 2015
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 15,728	[1]	$ 14,997		$ 14,931		$ 14,663		$ 12,979	[2]	$ 12,654		$ 12,453		$ 12,279		$ 60,319	$ 50,365	$ 47,453
Assets Noncurrent		$ 35,924								$ 33,970								35,924	33,970	26,134
FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		27,358	26,451	27,239
FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		6,958	6,763	6,704
FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		1,750	1,662	1,629
FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		3,528	3,379	3,342
FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		12,236	11,804	11,675
FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		5,827	5,697	6,251
FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		2,412	2,282	2,301
FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		8,239	7,979	8,552
FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[3]																	1,299	1,285	1,406
FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		21,774	21,068	21,633
FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		2,528	2,481	2,300
FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		1,502	1,384	1,588
FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		118	126	180
FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		4,148	3,991	4,068
FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[4]																	1,436	1,392	1,538
TNT Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		7,401
FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		18,075	16,574	12,984
FedEx Ground Segment [Member] | FedEx Ground [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		16,497	15,050	12,568
FedEx Ground Segment [Member] | FedEx Supply Chain [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		1,578	1,524	416
FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		6,443	6,200	6,191
FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues																		1,621	1,593	1,545
Corporate, eliminations and other
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[5]																	$ (579)	$ (453)	$ (506)

[1] The fourth quarter, third quarter, second quarter, and first quarter of 2017 include $124 million, $78 million, $58 million and $68 million, respectively, of TNT Express integration expenses and restructuring charges, and $20 million, $16 million, $10 million and $28 million, respectively, of increased intangible asset amortization as a result of the TNT Express acquisition. The fourth quarter of 2017 includes $39 million of charges for legal reserves related to certain pending CBP matters involving FedEx Trade Networks, $22 million of charges in connection with the settlement of and certain expected losses relating to independent contractor litigation matters at FedEx Ground and $24 million related to the retirement plans MTM gain.

[2] The fourth quarter of 2016 includes a $1.5 billion retirement plans MTM loss and TNT Express transaction, financing and integration-planning expenses and immaterial financial results from the time of acquisition totaling $79 million. In addition, the fourth quarter of 2016 includes a $76 million favorable tax impact from an internal corporate legal entity restructuring to facilitate the integration of FedEx Express and TNT Express and $11 million of expenses related to independent contractor litigation matters at FedEx Ground. The third quarter of 2016 includes provisions related to independent contractor litigation matters at FedEx Ground for $204 million and expenses related to the settlement of a CBP notice of action in the amount of $69 million (in each case, net of recognized immaterial insurance recovery), as well as TNT Express transaction, financing and integration-planning expenses of $25 million. The second quarter of 2016 includes provisions related to independent contractor litigation matters at FedEx Ground for $41 million and $19 million of TNT Express transaction, financing and integration-planning expenses.

[3] International domestic revenues represent our intra-country operations.

[4] Includes FedEx Trade Networks and FedEx SupplyChain Systems.

[5] Includes TNT Express’s revenue for 2016 from the time of acquisition (May 25, 2016).