Recent Accounting Guidance - Additional Information (Details) - USD ($) $ / shares in Units, $ 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	[2]	Feb. 29, 2016	[2]	Nov. 30, 2015	[2]	Aug. 31, 2015	[2]	May 31, 2017		May 31, 2016	[4]	May 31, 2015	[5]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Lease liability and related right-of-use asset	$ 13,000																$ 13,000
Operating income	$ 1,581	[1]	$ 1,025		$ 1,167		$ 1,264		$ (68)		$ 864		$ 1,137		$ 1,144		5,037	[3]	$ 3,077		$ 1,867
ASU 201609 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Share-based payment tax benefit																	$ 55
Share-based payment change effect on diluted EPS																	$ 0.17
ASU 201703 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating income																	$ 471

[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] Includes TNT Express integration expenses and restructuring charges of $327 million, increased intangible asset amortization of $74 million as a result of the TNT Express acquisition, and a gain of $24 million associated with our mark-to-market pension accounting. These expenses are included in “Eliminations, corporate and other,” the FedEx Express segment and the TNT Express segment. Also includes $39 million of charges for legal reserves related to certain pending U.S. Customs and Border Protection (“CBP”) matters involving FedEx Trade Networks and $22 million of charges in connection with the settlement of and certain expected losses relating to independent contractor litigation matters at FedEx Ground. See Note 18 below for additional information.

[4] Includes a $1.5 billion loss associated with our mark-to-market pension accounting. Also includes provisions for the settlement of and expected losses related to independent contractor litigation matters at FedEx Ground for $256 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, and transaction and integration-planning expenses related to our TNT Express acquisition of $113 million.

[5] Includes a $2.2 billion loss associated with our mark-to-market pension accounting, $276 million of impairment and related charges resulting from the decision to permanently retire and adjust the retirement schedule of certain aircraft and related engines, and a $197 million charge to increase the legal reserve associated with the settlement of a legal matter at FedEx Ground to the amount of the settlement.