Supplemental Information (Net Sales by Product Category) (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Net sales:
Net sales	$ 2,994	$ 3,089	$ 3,134
Spirits [Member]
Net sales:
Net sales	2,805	2,901	2,955
Wine [Member]
Net sales:
Net sales	$ 189	$ 188	$ 179