Condensed Consolidating Statements of Comprehensive Income (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
Condensed Statement Of Income Captions [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
OPERATING EXPENSES:
Salaries and employee benefits																	21,542		18,581		17,110
Purchased transportation																	13,630		9,966		8,483
Rentals and landing fees																	3,240		2,854		2,682
Depreciation and amortization																	2,995		2,631		2,611
Fuel																	2,773		2,399		3,720
Maintenance and repairs																	2,374		2,108		2,099
Impairment and other charges																					276
Retirement plans mark-to-market adjustment	(24)								1,500								(24)		1,498		2,190
Other																	8,752		7,251		6,415
OPERATING EXPENSES																	55,282		47,288		45,586
OPERATING INCOME	1,581	[1]	1,025		1,167		1,264		(68)	[2]	864		1,137		1,144		5,037	[3]	3,077	[4]	1,867	[5]
OTHER INCOME (EXPENSE):
Interest, net																	(479)		(315)		(221)
Other, net																	21		(22)		(19)
INCOME BEFORE INCOME TAXES																	4,579		2,740		1,627
PROVISION FOR INCOME TAXES																	1,582		920		577
NET INCOME	$ 1,020	[1]	$ 562		$ 700		$ 715		$ (70)	[2]	$ 507		$ 691		$ 692		2,997		1,820		1,050
COMPREHENSIVE INCOME																	2,751		1,479		716
Consolidation Eliminations [Member]
Condensed Statement Of Income Captions [Line Items]
REVENUES																	(302)		(325)		(381)
OPERATING EXPENSES:
Purchased transportation																	(125)		(134)		(197)
Rentals and landing fees																	(6)		(6)		(5)
Other																	(171)		(185)		(179)
OPERATING EXPENSES																	(302)		(325)		(381)
OTHER INCOME (EXPENSE):
Equity in earnings of subsidiaries																	(3,065)		(2,099)		(1,387)
INCOME BEFORE INCOME TAXES																	(3,065)		(2,099)		(1,387)
NET INCOME																	(3,065)		(2,099)		(1,387)
COMPREHENSIVE INCOME																	(3,065)		(2,099)		(1,387)
Parent Company [Member]
OPERATING EXPENSES:
Salaries and employee benefits																	123		119		106
Rentals and landing fees																	5		5		5
Depreciation and amortization																	1		1		1
Maintenance and repairs																	1		1		1
Intercompany charges, net																	(434)		(645)		(450)
Other																	304		519		337
OTHER INCOME (EXPENSE):
Equity in earnings of subsidiaries																	2,997		1,820		1,050
Interest, net																	(507)		(355)		(247)
Intercompany charges, net																	508		369		253
Other, net																	(1)		(14)		(6)
INCOME BEFORE INCOME TAXES																	2,997		1,820		1,050
NET INCOME																	2,997		1,820		1,050
COMPREHENSIVE INCOME																	2,922		1,746		1,053
Guarantor Subsidiaries [Member[
Condensed Statement Of Income Captions [Line Items]
REVENUES																	44,823		42,143		39,420
OPERATING EXPENSES:
Salaries and employee benefits																	16,696		15,880		14,626
Purchased transportation																	8,260		7,380		5,802
Rentals and landing fees																	2,517		2,484		2,322
Depreciation and amortization																	2,538		2,399		2,370
Fuel																	2,476		2,324		3,632
Maintenance and repairs																	2,086		1,954		1,949
Impairment and other charges																					276
Retirement plans mark-to-market adjustment																	(75)		1,414		2,075
Intercompany charges, net																	182		425		117
Other																	5,734		5,274		4,946
OPERATING EXPENSES																	40,414		39,534		38,115
OPERATING INCOME																	4,409		2,609		1,305
OTHER INCOME (EXPENSE):
Equity in earnings of subsidiaries																	68		279		337
Interest, net																	27		27		23
Intercompany charges, net																	(296)		(354)		(265)
Other, net																	(134)		(14)		(32)
INCOME BEFORE INCOME TAXES																	4,074		2,547		1,368
PROVISION FOR INCOME TAXES																	1,439		818		390
NET INCOME																	2,635		1,729		978
COMPREHENSIVE INCOME																	2,580		1,704		929
Non Guarantor Subsidiaries [Member]
Condensed Statement Of Income Captions [Line Items]
REVENUES																	15,798		8,547		8,414
OPERATING EXPENSES:
Salaries and employee benefits																	4,723		2,582		2,378
Purchased transportation																	5,495		2,720		2,878
Rentals and landing fees																	724		371		360
Depreciation and amortization																	456		231		240
Fuel																	297		75		88
Maintenance and repairs																	287		153		149
Retirement plans mark-to-market adjustment																	51		84		115
Intercompany charges, net																	252		220		333
Other																	2,885		1,643		1,311
OPERATING EXPENSES																	15,170		8,079		7,852
OPERATING INCOME																	628		468		562
OTHER INCOME (EXPENSE):
Interest, net																	1		13		3
Intercompany charges, net																	(212)		(15)		12
Other, net																	156		6		19
INCOME BEFORE INCOME TAXES																	573		472		596
PROVISION FOR INCOME TAXES																	143		102		187
NET INCOME																	430		370		409
COMPREHENSIVE INCOME																	$ 314		$ 128		$ 121

[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.