Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
Jul. 31, 2019	Jul. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 186	$ 200
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(13)	(12)
Cash flow hedge adjustments	9	23
Postretirement benefits adjustments	3	3
Net other comprehensive income (loss)	(1)	14
Comprehensive income	$ 185	$ 214

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