Supplemental Information (Net Sales by Geography) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Net sales:
Net sales	$ 3,946	$ 3,784	$ 3,614
UNITED STATES
Net sales:
Net sales	1,624	1,562	1,522
Europe [Member]
Net sales:
Net sales	1,264	1,147	1,073
Australia [Member]
Net sales:
Net sales	469	510	482
Other Countries [Member]
Net sales:
Net sales	$ 589	$ 565	$ 537