Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 190	$ 186	$ 545	$ 543
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(30)	(62)	(58)	(108)
Cash flow hedge adjustments	8	34	20	61
Postretirement benefits adjustments	5	4	15	20
Net other comprehensive income (loss)	(17)	(24)	(23)	(27)
Comprehensive income	$ 173	$ 162	$ 522	$ 516