Unaudited condensed consolidated interim statements of equity - USD ($) $ in Millions	Total	Equity attributable to the shareholders of Li-Cycle Holdings Corp.	Number of common shares	Common stock and additional paid-in capital	Accumulated deficit	Accumulated other comprehensive loss	Non-controlling interest
Beginning balance, common shares, outstanding (in shares) at Dec. 31, 2022			22,012,500
Beginning balance, equity at Dec. 31, 2022	$ 501.6	$ 501.4		$ 635.3	$ (133.6)	$ (0.3)	$ 0.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Settlement of RSUs (in shares)			100,000
Settlement of RSUs	0.0
Exercise of stock options (in shares)			162,500
Exercise of stock options	0.0
Stock-based compensation - RSUs	8.5	8.5		8.5
Stock-based compensation - options	2.8	2.8		2.8
Payment to the holders of non-controlling interest in subsidiary	(0.6)	(0.4)		(0.4)			(0.2)
Comprehensive loss	(99.1)	(99.1)			(99.1)
Net loss	(99.1)	(99.1)			(99.1)
Ending balance, common shares, outstanding (in shares) at Sep. 30, 2023			22,275,000
Ending balance, equity at Sep. 30, 2023	413.2	413.2		646.2	(232.7)	(0.3)	0.0
Beginning balance, common shares, outstanding (in shares) at Jun. 30, 2023			22,225,000
Beginning balance, equity at Jun. 30, 2023	439.9	439.9		642.2	(202.0)	(0.3)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Settlement of RSUs (in shares)			37,500
Settlement of RSUs	0.0
Exercise of stock options (in shares)			12,500
Exercise of stock options	0.0
Stock-based compensation - RSUs	3.0	3.0		3.0
Stock-based compensation - options	1.0	1.0		1.0
Comprehensive loss	(30.7)	(30.7)			(30.7)
Net loss	(30.7)	(30.7)			(30.7)
Ending balance, common shares, outstanding (in shares) at Sep. 30, 2023			22,275,000
Ending balance, equity at Sep. 30, 2023	$ 413.2	413.2		646.2	(232.7)	(0.3)	0.0
Beginning balance, common shares, outstanding (in shares) at Dec. 31, 2023	22,200,000		22,200,000
Beginning balance, equity at Dec. 31, 2023	$ 376.4	376.4		648.3	(271.6)	(0.3)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Settlement of RSUs (in shares)			300,000
Settlement of RSUs	0.0
Issuance of common stock in connection with the ATM Program (in shares)			700,000
Issuance of common stock in connection with the ATM Program	1.2	1.2		1.2
Stock-based compensation - RSUs	6.1	6.1		6.1
Stock-based compensation - options	0.0	0.0		0.0
Comprehensive loss	(88.4)	(88.4)			(88.4)
Net loss	$ (88.4)	(88.4)			(88.4)
Ending balance, common shares, outstanding (in shares) at Sep. 30, 2024	23,200,000		23,200,000
Ending balance, equity at Sep. 30, 2024	$ 295.3	295.3		655.6	(360.0)	(0.3)	0.0
Beginning balance, common shares, outstanding (in shares) at Jun. 30, 2024			22,500,000
Beginning balance, equity at Jun. 30, 2024	235.7	235.7		652.5	(416.5)	(0.3)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Settlement of RSUs (in shares)			0
Settlement of RSUs	0.0
Issuance of common stock in connection with the ATM Program (in shares)			700,000
Issuance of common stock in connection with the ATM Program	1.2	1.2		1.2
Stock-based compensation - RSUs	3.0	3.0		3.0
Stock-based compensation - options	(1.1)	(1.1)		(1.1)
Comprehensive loss	56.5	56.5			56.5
Net loss	$ 56.5	56.5			56.5
Ending balance, common shares, outstanding (in shares) at Sep. 30, 2024	23,200,000		23,200,000
Ending balance, equity at Sep. 30, 2024	$ 295.3	$ 295.3		$ 655.6	$ (360.0)	$ (0.3)	$ 0.0