Document And Entity Information - shares	8 Months Ended
	Sep. 30, 2021	Nov. 12, 2021
Document Information Line Items
Entity Registrant Name	HENNESSY CAPITAL INVESTMENT CORP. VI
Trading Symbol	HCVI
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001842937
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	true
Entity Ex Transition Period	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-40846
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-1626937
Entity Address, Address Line One	3415 N
Entity Address, Address Line Two	Pines Way
Entity Address, Address Line Three	Suite 204
Entity Address, City or Town	Wilson
Entity Address, State or Province	WY
Entity Address, Postal Zip Code	83014
City Area Code	(307)
Local Phone Number	201-1903
Title of 12(b) Security	Shares of Class A common stock, par value $0.0001 per share, included as part of the Units
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Class A Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		34,092,954
Class B Common Stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		8,625,000