Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Oct. 31, 2018	Jul. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Income Statement [Abstract]
Sales	$ 1,161		$ 1,166		$ 2,148	$ 2,095
Excise taxes	251		252		472	458
Net sales	910		914		1,676	1,637
Cost of sales	320		304		563	534
Gross profit	590		610		1,113	1,103
Advertising expenses	102		109		200	196
Selling, general, and administrative expenses	161		162		329	323
Other expense (income), net	(5)		(10)		(12)	(11)
Operating income	332		349		596	595
Non-operating postretirement expense	2		3		4	5
Interest income	(2)		(1)		(4)	(2)
Interest expense	22		16		44	32
Income before income taxes	310		331		552	560
Income taxes	61		92		103	143
Net income	$ 249	$ 200	$ 239	$ 178	$ 449	$ 417
Earnings per share:
Basic (dollars per share)	$ 0.52		$ 0.50		$ 0.93	$ 0.87
Diluted (dollars per share)	$ 0.52		$ 0.49		$ 0.93	$ 0.86