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, 2023	May 31, 2022
Property Plant And Equipment [Line Items]
Net Book Value at May 31,	$ 40,698	$ 38,091
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,	$ 16,973	15,949
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,	$ 2,038	2,163
Package Handling and Ground Support Equipment [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 15 years
Net Book Value at May 31,	$ 7,562	6,447
Information Technology [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 7 years
Net Book Value at May 31,	$ 1,859	1,907
Vehicles And Trailers [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 15 years
Net Book Value at May 31,	$ 3,996	4,004
Facilities and Other [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	1 to 33 years
Net Book Value at May 31,	$ 8,270	$ 7,621