General - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 17,824	$ 16,313	$ 34,876	$ 31,610
FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		9,604	9,076	18,826	17,476
FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		5,142	4,525	9,941	8,770
FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,918	1,673	3,877	3,337
FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		429	416	846	816
FedEx Trade Networks Operating Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		966	834	1,850	1,633
Operating Segments | FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		9,604	9,076	18,826	17,476
Operating Segments | FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,948	1,787	3,834	3,537
Operating Segments | FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		444	432	912	882
Operating Segments | FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,060	922	2,012	1,800
Operating Segments | FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,452	3,141	6,758	6,219
Operating Segments | FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,896	1,865	3,770	3,628
Operating Segments | FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		885	815	1,735	1,585
Operating Segments | FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,781	2,680	5,505	5,213
Operating Segments | FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[1]	1,203	1,228	2,334	2,284
Operating Segments | FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		7,436	7,049	14,597	13,716
Operating Segments | FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		792	688	1,522	1,301
Operating Segments | FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		564	541	1,097	995
Operating Segments | FedEx Express Segment [Member] | International Economy Freight
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		554	481	1,073	862
Operating Segments | FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		83	100	168	183
Operating Segments | FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,993	1,810	3,860	3,341
Operating Segments | FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		175	217	369	419
Operating Segments | FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		5,142	4,525	9,941	8,770
Operating Segments | FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,918	1,673	3,877	3,337
Operating Segments | FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		429	416	846	816
Eliminations [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ (235)	$ (211)	$ (464)	$ (422)

[1] International domestic revenues relate to our intra-country operations.