Description of Business and Summary of Significant Accounting Policies (Details 3) $ in Millions	12 Months Ended
	May 31, 2016 USD ($)	May 31, 2015 USD ($)	May 31, 2014 USD ($)	May 31, 2013	May 31, 2012
Depreciation [Abstract]
Depreciation expense, excluding gains and losses on sales of property and equipment	$ 2,600	$ 2,600	$ 2,600
Depreciable Life Range For Majority Of Aircraft Costs	15 to 30
Number of Aircraft With Shortened Depreciable Lives		23		76	54
Number of Aircraft Engines With Shortened Depreciable Lives		57
Incremental Depreciation Expense			$ 74
TNT PPE Fair Value	$ 1,100