Consolidated Statements of Changes in (Deficit) Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Deferred Compensation [Member]	Noncontrolling Interest In Subsidiaries [Member]
Balance at at Oct. 31, 2011	$ (14,375)	$ 13	$ 687,857	$ (701,336)	$ 15	$ (53)	$ 53	$ (924)
Balance at (in shares) at Oct. 31, 2011		138,400,497
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common stock (in shares)		45,012,306
Sale of common stock	64,003	5	63,998
Common stock issued for acquisition	0
Share based compensation	2,054		2,054
Stock issued under benefit plans (in shares)		2,443,320
Stock issued under benefit plans	548		548
Preferred stock dividends	(3,201)		(3,201)
Noncontrolling interest in subsidiaries	(411)							(411)
Sale of noncontrolling interest in subsidiary	954
Effect of foreign currency translation	51				51
Net loss attributable to FuelCell Energy, Inc.	(35,495)			(35,495)
Adjustment for Modification of Redeemable Preferred Stock of Subsidiary			0
Balance at at Oct. 31, 2012	14,128	18	751,256	(736,831)	66	(53)	53	(381)
Balance at (in shares) at Oct. 31, 2012		185,856,123
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common stock (in shares)	4,300,000	4,295,800
Sale of common stock	5,548	1	5,547
Common stock issued for acquisition (in shares)	3,526,764
Common stock issued for acquisition	3,563	1	3,562
Common stock issued to settle make-whole obligation, value	600
Share based compensation	2,226		2,226
Stock issued under benefit plans (in shares)		2,631,715
Stock issued under benefit plans	(173)		(173)
Reclass of noncontrolling interest due to liquidation of subsidiaries	0	0	(562)	0	0	0	0	562
Preferred stock dividends	(3,200)		(3,200)
Noncontrolling interest in subsidiaries	(961)							(961)
Sale of noncontrolling interest in subsidiary								954
Effect of foreign currency translation	35				35
Net loss attributable to FuelCell Energy, Inc.	(34,358)			(34,358)
Balance at at Oct. 31, 2013	(13,192)	20	758,656	(771,189)	101	(53)	53	(780)
Balance at (in shares) at Oct. 31, 2013	196,310,402	196,310,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common stock (in shares)		59,683,252
Sale of common stock	105,966	6	105,960
Common stock issued for convertible note conversions including interest, shares	24,766,752
Common stock issued for convertible note conversions including interest, value		3	33,303
Common stock issued for acquisition	0
Common stock issued to settle make-whole obligation, shares	5,514,272
Common stock issued to settle make-whole obligation, value			12,883
Share based compensation	2,908		2,908
Stock issued under benefit plans (in shares)		913,627
Stock issued under benefit plans	(1,079)		(1,079)
Preferred stock dividends	(3,200)		(3,200)
Adjustment for deferred compensation	(28,302)
Treasury Stock, Shares, Acquired						(42)
Deferred Compensation Arrangement with Individual, Compensation Expense							42
Noncontrolling interest in subsidiaries	(758)							(758)
Effect of foreign currency translation	(260)				(260)
Net loss attributable to FuelCell Energy, Inc.	(38,125)			(38,125)
Balance at at Oct. 31, 2014	$ 98,449	$ 29	$ 909,431	$ (809,314)	$ (159)	$ (95)	$ 95	$ (1,538)
Balance at (in shares) at Oct. 31, 2014	287,160,003	287,160,003