Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Balance at beginning of year	$ 129	$ 164	$ 161
Increases for tax positions taken in the current year	3	3
Increases for tax positions taken in prior years	69	4	31
Decreases for tax positions taken in prior years	(6)	(10)	(4)
Settlements	(6)	(31)	(21)
Changes due to currency translation	3	(1)	(3)
Balance at end of year	$ 192	$ 129	$ 164