Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2017
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Balance at beginning of year	$ 161	$ 67	$ 49
Increases for tax positions taken in the current year		3
Increases for tax positions taken in prior years	31	103	8
Increase for business acquisition			17
Decreases for tax positions taken in prior years	(4)	(10)	(1)
Settlements	(21)	(2)	(4)
Decreases from lapse of statute of limitations			(2)
Changes due to currency translation	(3)
Balance at end of year	$ 164	$ 161	$ 67