Income Taxes - Schedule of Components of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Current provision
Federal	$ 269	$ 513	$ 795
State and local	88	72	102
Foreign	285	200	214
Current Provision, Total	642	785	1,111
Deferred provision (benefit)
Federal	989	155	(474)
State and local	59	(18)	(47)
Foreign	(108)	(2)	(13)
Deferred Provision, Total	940	135	(534)
Provision for Income Taxes, Total	$ 1,582	$ 920	$ 577