Document and Entity Information - shares	6 Months Ended
	Oct. 31, 2017	Nov. 30, 2017
Document Information [Line Items]
Entity Registrant Name	BROWN FORMAN CORP
Entity Central Index Key	0000014693
Document Type	10-Q
Document Period End Date	Oct. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--04-30
Entity Filer Category	Large Accelerated Filer
Common stock, Class A, voting [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		169,061,063
Common stock, Class B, nonvoting [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		215,276,608