Description of Business Segments and Summary of Significant Accounting Policies - Schedule of Depreciable Lives and Net Book Value of Our Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2022	May 31, 2021
Property Plant And Equipment [Line Items]
Net Book Value at May 31,	$ 38,091	$ 35,752
Wide-body Aircraft and Related Equipment [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	15 to 30 years
Net Book Value at May 31,	$ 15,949	14,812
Narrow-body and Feeder Aircraft and Related Equipment [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	5 to 30 years
Net Book Value at May 31,	$ 2,163	2,307
Package Handling and Ground Support Equipment [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 30 years
Net Book Value at May 31,	$ 6,447	5,269
Information Technology [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	2 to 10 years
Net Book Value at May 31,	$ 1,907	1,863
Vehicles And Trailers [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 15 years
Net Book Value at May 31,	$ 4,004	4,033
Facilities and Other [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	2 to 40 years
Net Book Value at May 31,	$ 7,621	$ 7,468