DESCRIPTION OF BUSINESS SEGMENTS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Depreciable Lives and Net Book Value of Property and Equipment (Details) - USD ($) $ in Millions	May 31, 2026	May 31, 2025
Wide-body aircraft and related equipment
Property Plant And Equipment [Line Items]
Net book value	$ 18,027	$ 18,202
Wide-body aircraft and related equipment \| Minimum
Property Plant And Equipment [Line Items]
Range	18 years
Wide-body aircraft and related equipment \| Maximum
Property Plant And Equipment [Line Items]
Range	30 years
Narrow-body and feeder aircraft and related equipment
Property Plant And Equipment [Line Items]
Net book value	$ 1,635	1,750
Narrow-body and feeder aircraft and related equipment \| Minimum
Property Plant And Equipment [Line Items]
Range	5 years
Narrow-body and feeder aircraft and related equipment \| Maximum
Property Plant And Equipment [Line Items]
Range	30 years
Package handling and ground support equipment
Property Plant And Equipment [Line Items]
Net book value	$ 7,430	7,573
Package handling and ground support equipment \| Minimum
Property Plant And Equipment [Line Items]
Range	3 years
Package handling and ground support equipment \| Maximum
Property Plant And Equipment [Line Items]
Range	15 years
Information technology
Property Plant And Equipment [Line Items]
Net book value	$ 1,422	1,568
Information technology \| Minimum
Property Plant And Equipment [Line Items]
Range	3 years
Information technology \| Maximum
Property Plant And Equipment [Line Items]
Range	7 years
Vehicles and trailers
Property Plant And Equipment [Line Items]
Net book value	$ 4,285	4,075
Vehicles and trailers \| Minimum
Property Plant And Equipment [Line Items]
Range	3 years
Vehicles and trailers \| Maximum
Property Plant And Equipment [Line Items]
Range	15 years
Facilities and other
Property Plant And Equipment [Line Items]
Net book value	$ 9,245	$ 8,474
Facilities and other \| Minimum
Property Plant And Equipment [Line Items]
Range	1 year
Facilities and other \| Maximum
Property Plant And Equipment [Line Items]
Range	33 years