Description of Business and Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Millions	12 Months Ended
	May 31, 2016	May 31, 2015
Property And Equipment [Line Items]
Net property and equipment	$ 24,284	$ 20,875
Wide Body Aircraft And Related Equipment [Member]
Property And Equipment [Line Items]
Depreciable lives range	15 to 30 years
Net property and equipment	$ 8,356	7,548
Narrow Body And Feeder Aircraft And Related Equipment [Member]
Property And Equipment [Line Items]
Depreciable lives range	5 to 18 years
Net property and equipment	$ 3,180	2,943
Package Handling And Ground Support Equipment [Member]
Property And Equipment [Line Items]
Depreciable lives range	3 to 30 years
Net property and equipment	$ 3,249	2,410
Vehicles [Member]
Property And Equipment [Line Items]
Depreciable lives range	3 to 15 years
Net property and equipment	$ 3,084	2,717
Computer And Electronic Equipment [Member]
Property And Equipment [Line Items]
Depreciable lives range	2 to 10 years
Net property and equipment	$ 1,051	866
Facilities And Other Property [Member]
Property And Equipment [Line Items]
Depreciable lives range	2 to 40 years
Net property and equipment	$ 5,364	$ 4,391