Document and Entity Information - shares	9 Months Ended
	Jul. 31, 2023	Sep. 05, 2023
Cover [Abstract]
Entity Registrant Name	FUELCELL ENERGY, INC.
Entity Central Index Key	0000886128
Document Type	10-Q
Document Period End Date	Jul. 31, 2023
Current Fiscal Year End Date	--10-31
Document Quarterly Report	true
Document Transition Report	false
Amendment Flag	false
Entity File Number	1-14204
Entity Tax Identification Number	06-0853042
Entity Address, Address Line One	3 Great Pasture Road
Entity Address, City or Town	Danbury
Entity Address, State or Province	CT
Entity Incorporation, State or Country Code	DE
Entity Address, Postal Zip Code	06810
City Area Code	203
Local Phone Number	825-6000
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	FCEL
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		450,626,333
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3