Condensed Consolidated Statements of Stockholders’ Equity - USD ($) shares in Millions, $ in Millions	Total	Total HC2 Stockholders' Equity	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	2.9	2.9		2.9
Fair value adjustment of redeemable noncontrolling interest	(1.2)	(1.2)		(1.2)
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	(0.4)	(0.4)		(0.4)
Issuance of common stock (in shares)			0.9
Issuance of common stock	0.0	0.0
Transactions with noncontrolling interests	(49.2)	6.1		6.1				(55.3)
Net loss (loss)	(71.0)	(70.0)				(70.0)		(1.0)
Other comprehensive income (loss)	41.4	33.0					33.0	8.4
Ending balance (in shares) at Jun. 30, 2020			46.6
Ending balance at Jun. 30, 2020	365.2	319.3	$ 0.0	288.5	(4.2)	(166.7)	201.7	45.9
Beginning balance at Dec. 31, 2019	21.6
Increase (Decrease) in Temporary Equity [Roll Forward]
Fair value adjustment of redeemable noncontrolling interest	1.2
Transactions with noncontrolling interests	(4.0)
Net income (loss)	(1.5)
Other comprehensive income	1.4
Ending balance at Jun. 30, 2020	18.7
Beginning balance (in shares) at Mar. 31, 2020			46.5
Beginning balance at Mar. 31, 2020	60.5	14.1	$ 0.0	282.7	(4.2)	(179.8)	(84.6)	46.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	0.3	0.3		0.3
Preferred stock dividend	(0.2)	(0.2)		(0.2)
Issuance of common stock (in shares)			0.1
Issuance of common stock	0.0	0.0		0.0
Transactions with noncontrolling interests	(12.4)	2.8		2.8				(15.2)
Net loss (loss)	27.1	13.1				13.1		14.0
Other comprehensive income (loss)	287.0	286.3					286.3	0.7
Ending balance (in shares) at Jun. 30, 2020			46.6
Ending balance at Jun. 30, 2020	365.2	319.3	$ 0.0	288.5	(4.2)	(166.7)	201.7	45.9
Beginning balance at Mar. 31, 2020	18.6
Increase (Decrease) in Temporary Equity [Roll Forward]
Fair value adjustment of redeemable noncontrolling interest	(2.9)
Transactions with noncontrolling interests	1.5
Net income (loss)	1.4
Other comprehensive income	0.1
Ending balance at Jun. 30, 2020	18.7
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	1.3	1.3		1.3
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	(0.3)	(0.3)		(0.3)
Issuance of common stock (in shares)			1.1
Issuance of common stock	0.7	0.7		0.7
Purchase of preferred stock by subsidiary	(0.2)	(0.2)		(0.2)
Transactions with noncontrolling interests	(14.2)	0.8		0.8				(15.0)
Other	(2.9)	(2.9)		(2.9)
Net loss (loss)	(13.0)	(10.9)				(10.9)		(2.1)
Other comprehensive income (loss)	(58.8)	(58.7)					(58.7)	(0.1)
Ending balance (in shares) at Jun. 30, 2021			77.8
Ending balance at Jun. 30, 2021	511.5	488.3	$ 0.1	354.8	(5.2)	(199.6)	338.2	23.2
Beginning balance at Dec. 31, 2020	15.7
Increase (Decrease) in Temporary Equity [Roll Forward]
Fair value adjustment of redeemable noncontrolling interest	0.3
Redemption of Series A and A-2 Preferred Stock	(10.4)
Transactions with noncontrolling interests	3.8
Net income (loss)	(3.2)
Ending balance at Jun. 30, 2021	6.2
Beginning balance (in shares) at Mar. 31, 2021			77.6
Beginning balance at Mar. 31, 2021	413.5	389.6	$ 0.1	355.7	(5.2)	(176.1)	215.1	23.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	0.6	0.6		0.6
Fair value adjustment of redeemable noncontrolling interest	(0.1)	(0.1)		(0.1)
Preferred stock dividend	(0.1)	(0.1)		(0.1)
Issuance of common stock (in shares)			0.2
Issuance of common stock	0.5	0.5		0.5
Purchase of preferred stock by subsidiary	(0.2)	(0.2)		(0.2)
Transactions with noncontrolling interests	(2.1)	(1.6)		(1.6)				(0.5)
Net loss (loss)	(23.7)	(23.5)				(23.5)		(0.2)
Other comprehensive income (loss)	123.1	123.1					123.1	0.0
Ending balance (in shares) at Jun. 30, 2021			77.8
Ending balance at Jun. 30, 2021	511.5	$ 488.3	$ 0.1	$ 354.8	$ (5.2)	$ (199.6)	$ 338.2	$ 23.2
Beginning balance at Mar. 31, 2021	18.0
Increase (Decrease) in Temporary Equity [Roll Forward]
Fair value adjustment of redeemable noncontrolling interest	0.1
Redemption of Series A and A-2 Preferred Stock	(10.4)
Transactions with noncontrolling interests	0.0
Net income (loss)	(1.5)
Ending balance at Jun. 30, 2021	$ 6.2