Disaggregated revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 910	$ 914	$ 1,676	$ 1,637
United States [Member]
Disaggregation of Revenue [Line Items]
Net sales	447	438
Developed International [Member]
Disaggregation of Revenue [Line Items]
Net sales	234	248
Emerging [Member]
Disaggregation of Revenue [Line Items]
Net sales	164	159
Travel Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	38	44
Non-branded and bulk [Member]
Disaggregation of Revenue [Line Items]
Net sales	27	25
Whiskey [Member]
Disaggregation of Revenue [Line Items]
Net sales	706	713
Tequila [Member]
Disaggregation of Revenue [Line Items]
Net sales	70	64
Vodka [Member]
Disaggregation of Revenue [Line Items]
Net sales	34	35
Wine [Member]
Disaggregation of Revenue [Line Items]
Net sales	62	63
Rest of portfolio [Member]
Disaggregation of Revenue [Line Items]
Net sales	11	14
Non-branded and bulk [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 27	$ 25