Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 177	$ 157	$ 526	$ 478
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(14)	14	(19)	13
Cash flow hedge adjustments	7	(2)	3	(3)
Postretirement benefits adjustments	5	5	24	14
Net other comprehensive income (loss)	(2)	17	8	24
Comprehensive income	$ 175	$ 174	$ 534	$ 502