Document and Entity Information - shares	9 Months Ended
	Jan. 31, 2018	Feb. 28, 2018
Document Information [Line Items]
Entity Registrant Name	BROWN FORMAN CORP
Entity Central Index Key	0000014693
Document Type	10-Q
Document Period End Date	Jan. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
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		169,062,093
Common stock, Class B, nonvoting [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		311,827,161