Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 156	$ 150
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(24)	(16)
Cash flow hedge adjustments	16	5
Postretirement benefits adjustments	4	4
Net other comprehensive income (loss)	(4)	(7)
Comprehensive income	$ 152	$ 143