Business Segment Information (Details 2) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Feb. 29, 2016	Nov. 30, 2015	May 31, 2015	May 31, 2016	May 31, 2015	May 31, 2014
Business Segment Information Table Detail [Line Items]
Asset Impairment Charges			$ 276		$ 276
Mark to Market pension accounting					$ 2,200
U.S. CBP notice of action settlement	$ 69			$ 69
Ground independent contractor litigation provision	$ 204	$ 41	$ 197	256
Corporate, eliminations and other [Member]
Business Segment Information Table Detail [Line Items]
Mark to Market pension accounting				$ 1,500		$ 15