Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 219	$ 231	$ 783	$ 699
Other comprehensive income (loss), net of tax:
Currency translation adjustments	47	6	113	3
Cash flow hedge adjustments	(33)	(1)	(72)	1
Postretirement benefits adjustments	5	3	17	10
Net other comprehensive income (loss)	19	8	58	14
Comprehensive income	$ 238	$ 239	$ 841	$ 713