Disaggregated revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 904	$ 878	$ 2,580	$ 2,515
United States [Member]
Disaggregation of Revenue [Line Items]
Net sales	413	387	1,217	1,180
Developed International [Member]
Disaggregation of Revenue [Line Items]
Net sales	269	275	718	716
Emerging [Member]
Disaggregation of Revenue [Line Items]
Net sales	165	163	460	445
Travel Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	33	34	109	108
Non-branded and bulk [Member]
Disaggregation of Revenue [Line Items]
Net sales	24	19	76	66
Whiskey [Member]
Disaggregation of Revenue [Line Items]
Net sales	709	688	2,017	1,958
Tequila [Member]
Disaggregation of Revenue [Line Items]
Net sales	68	63	200	185
Vodka [Member]
Disaggregation of Revenue [Line Items]
Net sales	36	39	96	105
Wine [Member]
Disaggregation of Revenue [Line Items]
Net sales	51	50	153	155
Rest of portfolio [Member]
Disaggregation of Revenue [Line Items]
Net sales	16	19	38	46
Non-branded and bulk [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 24	$ 19	$ 76	$ 66