Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Apr. 30, 2018	May 31, 2018	Oct. 31, 2017
Document Information [Line Items]
Entity Registrant Name	BROWN FORMAN CORP
Entity Central Index Key	0000014693
Document Type	10-K
Document Period End Date	Apr. 30, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--04-30
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 14.9
Common stock, Class A, voting [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		169,048,402
Common Stock, Class B, nonvoting [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		312,063,220