Document and Entity Information - shares	6 Months Ended
	Apr. 30, 2024	Jun. 05, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Apr. 30, 2024
Document Transition Report	false
Entity File Number	1-14204
Entity Registrant Name	FUELCELL ENERGY, INC.
Entity Incorporation, State or Country Code	DE
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 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		497,046,680
Entity Central Index Key	0000886128
Amendment Flag	false
Current Fiscal Year End Date	--10-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2