General - Schedule of Revenue by Service Type (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		$ 17,324	$ 17,824	$ 34,372	$ 34,876
Operating Segments | FedEx Express Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		9,084	9,604	18,029	18,826
Operating Segments | FedEx Express Segment [Member] | U.S. overnight box [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,864	1,948	3,730	3,834
Operating Segments | FedEx Express Segment [Member] | U.S. overnight envelope [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		457	444	936	912
Operating Segments | FedEx Express Segment [Member] | U.S. deferred [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		980	1,060	1,936	2,012
Operating Segments | FedEx Express Segment [Member] | Total U.S. domestic package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		3,301	3,452	6,602	6,758
Operating Segments | FedEx Express Segment [Member] | International priority [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,817	1,896	3,634	3,770
Operating Segments | FedEx Express Segment [Member] | International economy [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		873	885	1,728	1,735
Operating Segments | FedEx Express Segment [Member] | Total international export package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		2,690	2,781	5,362	5,505
Operating Segments | FedEx Express Segment [Member] | International domestic [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[1]	1,165	1,203	2,241	2,334
Operating Segments | FedEx Express Segment [Member] | Total package revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		7,156	7,436	14,205	14,597
Operating Segments | FedEx Express Segment [Member] | U.S. freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		698	792	1,393	1,522
Operating Segments | FedEx Express Segment [Member] | International priority freight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		473	564	937	1,097
Operating Segments | FedEx Express Segment [Member] | International Economy Freight
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		541	554	1,057	1,073
Operating Segments | FedEx Express Segment [Member] | International Airfreight [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		70	83	136	168
Operating Segments | FedEx Express Segment [Member] | Total freight revenue [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,782	1,993	3,523	3,860
Operating Segments | FedEx Express Segment [Member] | Other [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		146	175	301	369
Operating Segments | FedEx Ground Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		5,315	5,142	10,494	9,941
Operating Segments | FedEx Freight Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		1,844	1,918	3,749	3,877
Operating Segments | FedEx Services Segment [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues		5	4	9	13
Other and eliminations [Member]
Entity Wide Information Revenue From External Customer [Line Items]
Revenues	[2]	$ 1,076	$ 1,156	$ 2,091	$ 2,219

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

[2] Includes the FedEx Logistics, Inc. (“FedEx Logistics”) and FedEx Office and Print Services, Inc. (“FedEx Office”) operating segments.