Disaggregated revenues (Details) - USD ($) $ in Millions		3 Months Ended
		Jul. 31, 2018	Jul. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales		$ 766	$ 723
United States [Member]
Disaggregation of Revenue [Line Items]
Net sales		357	355
Developed International [Member]
Disaggregation of Revenue [Line Items]
Net sales	[1]	215	193
Emerging [Member]
Disaggregation of Revenue [Line Items]
Net sales	[2]	131	123
Travel Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	[3]	38	30
Non-branded and bulk [Member]
Disaggregation of Revenue [Line Items]
Net sales	[4]	25	22
Whiskey [Member]
Disaggregation of Revenue [Line Items]
Net sales	[5]	602	557
Tequila [Member]
Disaggregation of Revenue [Line Items]
Net sales	[6]	62	58
Vodka [Member]
Disaggregation of Revenue [Line Items]
Net sales	[7]	26	31
Wine [Member]
Disaggregation of Revenue [Line Items]
Net sales	[8]	40	42
Rest of portfolio [Member]
Disaggregation of Revenue [Line Items]
Net sales		11	13
Non-branded and bulk [Member]
Disaggregation of Revenue [Line Items]
Net sales	[4]	$ 25	$ 22

[1] Represents sales of branded products to “advanced economies” as defined by the International Monetary Fund (IMF), excluding the United States. Our largest developed international markets are the United Kingdom, Australia, and Germany.

[2] Represents sales of branded products to “emerging and developing economies” as defined by the IMF. Our largest emerging markets are Mexico and Poland.

[3] Represents sales of branded products to global duty-free customers, travel retail customers, and the U.S. military regardless of customer location.

[4] Includes sales of used barrels, bulk whiskey and wine, and contract bottling regardless of customer location.

[5] Includes all whiskey spirits and whiskey-based flavored liqueurs, ready-to-drink, and ready-to-pour products. The brands included in this category are the Jack Daniel's family of brands, Woodford Reserve, Canadian Mist, GlenDronach, BenRiach, Glenglassaugh, Old Forester, Early Times, Slane Irish Whiskey, and Coopers' Craft.

[6] Includes el Jimador, Herradura, New Mix, Pepe Lopez, and Antiguo.

[7] Includes Finlandia.

[8] Includes Korbel Champagne and Sonoma-Cutrer wines.