Loss Per Share - Schedule of Calculation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jan. 31, 2024	Jan. 31, 2023
Numerator
Net loss attributable to FuelCell Energy, Inc.	$ (19,793)	$ (18,622)
Series B preferred stock dividends	(800)	(800)
Net loss attributable to common stockholders	$ (20,593)	$ (19,422)
Denominator
Weighted average common shares outstanding - basic	451,637,041	405,803,753
Weighted average common shares outstanding - diluted	451,637,041	405,803,753
Net loss to common stockholders per share - basic	$ (0.05)	$ (0.05)
Net loss to common stockholders per share - diluted	$ (0.05)	$ (0.05)
Series B Preferred Stock
Numerator
Series B preferred stock dividends	$ (800)	$ (800)