Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 240	$ 282	$ 564	$ 468
Other comprehensive income (loss), net of tax:
Currency translation adjustments	4	11	66	(3)
Cash flow hedge adjustments	6	(7)	(39)	2
Postretirement benefits adjustments	5	3	12	7
Net other comprehensive income (loss)	15	7	39	6
Comprehensive income	$ 255	$ 289	$ 603	$ 474