Condensed Consolidated Statements of Stockholders’ (Deficit) Equity - USD ($) shares in Millions, $ in Millions	Total	Preferred stock	Total INNOVATE Stockholders' Equity (Deficit)	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Non- controlling Interest
Beginning balance (in shares) at Dec. 31, 2019				46.1
Beginning balance at Dec. 31, 2019	$ 443.6		$ 349.8	$ 0.0	$ 281.1	$ (3.3)	$ (96.7)	$ 168.7	$ 93.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	5.9		5.9		5.9
Fair value adjustment of redeemable noncontrolling interest	(1.4)		(1.4)		(1.4)
Taxes paid in lieu of shares issued for share-based compensation (in shares)				(0.4)
Taxes paid in lieu of shares issued for share-based compensation	(0.9)		(0.9)			(0.9)
Preferred stock dividend	(0.6)		(0.6)		(0.6)
Issuance of common stock (in shares)				1.6
Transactions with noncontrolling interests	(50.4)		6.9		6.9				(57.3)
Other	1.7		1.7		1.7
Net loss	(91.1)		(87.3)				(87.3)		(3.8)
Other comprehensive income (loss)	105.9		97.7					97.7	8.2
Ending balance (in shares) at Sep. 30, 2020				47.3
Ending balance at Sep. 30, 2020	412.7		371.8	$ 0.0	293.6	(4.2)	(184.0)	266.4	40.9
Beginning balance at Dec. 31, 2019	21.6
Temporary Equity
Fair value adjustment of redeemable noncontrolling interest	1.4
Issuance of redeemable noncontrolling interest	5.6	$ 0.0
Transactions with noncontrolling interests	(4.0)
Net loss	(3.0)
Other comprehensive income	1.3
Ending balance at Sep. 30, 2020	22.9
Beginning balance (in shares) at Dec. 31, 2019				46.1
Beginning balance at Dec. 31, 2019	443.6		349.8	$ 0.0	281.1	(3.3)	(96.7)	168.7	93.8
Ending balance (in shares) at Dec. 31, 2020				76.7
Ending balance at Dec. 31, 2020	600.2		559.8	$ 0.1	355.7	(4.2)	(188.7)	396.9	40.4
Beginning balance at Dec. 31, 2019	21.6
Ending balance at Dec. 31, 2020	15.7
Beginning balance (in shares) at Jun. 30, 2020				46.6
Beginning balance at Jun. 30, 2020	365.2		319.3	$ 0.0	288.5	(4.2)	(166.7)	201.7	45.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	3.0		3.0		3.0
Fair value adjustment of redeemable noncontrolling interest	(0.2)		(0.2)		(0.2)
Preferred stock dividend	(0.2)		(0.2)		(0.2)
Issuance of common stock (in shares)				0.7
Transactions with noncontrolling interests	(1.2)		0.8		0.8				(2.0)
Other	1.7		1.7		1.7
Net loss	(20.1)		(17.3)				(17.3)		(2.8)
Other comprehensive income (loss)	64.5		64.7					64.7	(0.2)
Ending balance (in shares) at Sep. 30, 2020				47.3
Ending balance at Sep. 30, 2020	412.7		371.8	$ 0.0	293.6	(4.2)	(184.0)	266.4	40.9
Beginning balance at Jun. 30, 2020	18.7
Temporary Equity
Fair value adjustment of redeemable noncontrolling interest	0.2
Issuance of redeemable noncontrolling interest	5.6
Transactions with noncontrolling interests	0.0
Net loss	(1.5)
Other comprehensive income	(0.1)
Ending balance at Sep. 30, 2020	22.9
Beginning balance (in shares) at Dec. 31, 2020				76.7
Beginning balance at Dec. 31, 2020	600.2		559.8	$ 0.1	355.7	(4.2)	(188.7)	396.9	40.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	1.7		1.7		1.7
Fair value adjustment of redeemable noncontrolling interest	(0.3)		(0.3)		(0.3)
Taxes paid in lieu of shares issued for share-based compensation	(1.0)		(1.0)			(1.0)
Preferred stock dividend	(1.4)		(1.4)		(1.4)
Issuance of common stock (in shares)				1.1
Issuance of common stock	0.7		0.7		0.7
Purchase of preferred stock by subsidiary	(0.3)		(0.3)		(0.3)
Transactions with noncontrolling interests	(31.3)		(21.6)		(21.6)				(9.7)
Other	(3.3)		(3.3)		(3.3)
Net loss	(225.9)		(222.8)				(222.8)		(3.1)
Other comprehensive income (loss)	(393.8)		(393.7)					(393.7)	(0.1)
Ending balance (in shares) at Sep. 30, 2021				77.8
Ending balance at Sep. 30, 2021	(54.7)		(82.2)	$ 0.1	331.2	(5.2)	(411.5)	3.2	27.5
Beginning balance at Dec. 31, 2020	15.7
Temporary Equity
Fair value adjustment of redeemable noncontrolling interest	0.4
Issuance of redeemable noncontrolling interest		19.1
Redemption of Series A and A-2 Preferred Stock	(10.4)
Transactions with noncontrolling interests	9.4
Net loss	(4.8)
Ending balance at Sep. 30, 2021	70.3
Beginning balance (in shares) at Jun. 30, 2021				77.8
Beginning balance at Jun. 30, 2021	511.5		488.3	$ 0.1	354.8	(5.2)	(199.6)	338.2	23.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	0.4		0.4		0.4
Preferred stock dividend	(1.1)		(1.1)		(1.1)
Purchase of preferred stock by subsidiary	(0.1)		(0.1)		(0.1)
Transactions with noncontrolling interests	(17.1)		(22.4)		(22.4)				5.3
Other	(0.4)		(0.4)		(0.4)
Net loss	(212.9)		(211.9)				(211.9)		(1.0)
Other comprehensive income (loss)	(335.0)		(335.0)					(335.0)
Ending balance (in shares) at Sep. 30, 2021				77.8
Ending balance at Sep. 30, 2021	(54.7)		$ (82.2)	$ 0.1	$ 331.2	$ (5.2)	$ (411.5)	$ 3.2	$ 27.5
Beginning balance at Jun. 30, 2021	6.2
Temporary Equity
Fair value adjustment of redeemable noncontrolling interest	0.1
Issuance of redeemable noncontrolling interest	40.9	$ 19.1
Transactions with noncontrolling interests	5.6
Net loss	(1.6)
Ending balance at Sep. 30, 2021	$ 70.3