Basic and Diluted Earnings (Loss) Per Common Share - Schedule of Reconciliation of Net Income (Loss) to Net Income (Loss) Used in Basic and Diluted EPS Calculations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Earnings Per Share [Abstract]
Net income (loss)	$ 12.4	$ (21.0)	$ (4.7)	$ (46.8)
Net (income) loss attributable to non-controlling interests and redeemable non-controlling interests	(1.7)	1.2	(1.4)	2.5
Net income (loss) attributable to INNOVATE Corp.	10.7	(19.8)	(6.1)	(44.3)
Less: Preferred stock dividends	0.3	2.2	0.7	2.5
Net income (loss) attributable to common stockholders and participating preferred stockholders	$ 10.4	$ (22.0)	$ (6.8)	$ (46.8)
Earnings (loss) allocable to common shares:
Weighted-average common shares outstanding - basic (in shares)	13,374,803	13,146,750	13,360,333	13,130,930
Unvested restricted stock (in shares)	267,063	0	0	0
Series A-3 and Series A-4 Preferred Stock (as converted) (in shares)	371,604	0	0	0
Total (in shares)	14,013,470	13,146,750	13,360,333	13,130,930
Percentage of earnings (loss) allocated to:
Common stock (as percent)	95.40%	100.00%	100.00%	100.00%
Unvested restricted stock (as a percent)	1.90%	0.00%	0.00%	0.00%
Series A-3 and Series A-4 Preferred Stock (as a percent)	2.70%	0.00%	0.00%	0.00%
Numerator for earnings (loss) per share:
Net income (loss) attributable to common stockholders - basic	$ 9.9	$ (22.0)	$ (6.8)	$ (46.8)
Effect of assumed shares under the treasury stock method for stock options and unvested restricted stock	0.0	0.0	0.0	0.0
Net income (loss) attributable to common stockholders and participating preferred stockholders, diluted	$ 9.9	$ (22.0)	$ (6.8)	$ (46.8)
Denominator for earnings (loss) per share:
Weighted-average common shares outstanding - basic (in shares)	13,374,803	13,146,750	13,360,333	13,130,930
Effect of assumed shares under the treasury stock method for stock options and unvested restricted stock (in shares)	593,201	0	0	0
Weighted-average common shares outstanding - diluted (in shares)	13,968,004	13,146,750	13,360,333	13,130,930
Earnings (Loss) per share
Basic (in usd per share)	$ 0.74	$ (1.67)	$ (0.51)	$ (3.56)
Diluted (in usd per share)	$ 0.71	$ (1.67)	$ (0.51)	$ (3.56)

Basic and Diluted Earnings (Loss) Per Common Share - Schedule of Reconciliation of Net Income (Loss) to Net Income (Loss) Used in Basic and Diluted EPS Calculations (Details) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2026

Jun. 30, 2025

Jun. 30, 2026

Jun. 30, 2025

Earnings Per Share [Abstract]

Net income (loss)

$ 12.4

$ (21.0)

$ (4.7)

$ (46.8)