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, 2024	May 31, 2023
Property Plant And Equipment [Line Items]
Net Book Value at May 31,	$ 41,491	$ 40,698
Wide-body Aircraft and Related Equipment [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	18 to 30 years
Net Book Value at May 31,	$ 17,936	16,973
Wide-body Aircraft and Related Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	30 years
Wide-body Aircraft and Related Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	18 years
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,	$ 1,849	2,038
Narrow-body and Feeder Aircraft and Related Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	30 years
Narrow-body and Feeder Aircraft and Related Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	5 years
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,	$ 7,607	7,562
Package Handling and Ground Support Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	15 years
Package Handling and Ground Support Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	3 years
Information Technology [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 7 years
Net Book Value at May 31,	$ 1,722	1,859
Information Technology [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	7 years
Information Technology [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	3 years
Vehicles And Trailers [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	3 to 15 years
Net Book Value at May 31,	$ 4,053	3,996
Vehicles And Trailers [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	15 years
Vehicles And Trailers [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	3 years
Facilities and Other [Member]
Property Plant And Equipment [Line Items]
Depreciable lives range	1 to 33 years
Net Book Value at May 31,	$ 8,324	$ 8,270
Facilities and Other [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	33 years
Facilities and Other [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment useful life	1 year