Prior Period Consolidated Financial Statements - Consolidated Statement of Cash Flows (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Cash flows - operating activities
Net income (loss)	$ (12.8)	$ (4.2)	$ (6.2)	$ 16.1
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net investment losses			21.3	31.0
Depreciation and intangible asset amortization			12.9	7.9
Share-based compensation expense			4.5	4.4
Loss (gain) from equity method investments, net of dividends or distributions			11.5	(3.8)
Changes in:
Insurance liabilities			126.8	275.2
Amounts due under reinsurance agreements			14.3	(310.4)
Income tax liabilities			(15.7)	93.0
Other operating assets and liabilities			(17.3)	(36.2)
Other, net			1.8	2.8
Net cash provided by operating activities			153.9	80.0
Cash flows - investing activities
Net cash used in investing activities			(44.6)	(296.1)
Cash flows - financing activities
Net cash provided by (used in) financing activities			(129.0)	132.5
Net decrease in cash			(19.7)	(83.6)
Cash at beginning of period			42.8	133.7
Cash at end of period	$ 23.1	50.1	23.1	50.1
Previously Reported
Cash flows - operating activities
Net income (loss)		(12.5)		2.0
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net investment losses				31.0
Depreciation and intangible asset amortization				7.9
Share-based compensation expense				4.4
Loss (gain) from equity method investments, net of dividends or distributions				(3.8)
Changes in:
Insurance liabilities				411.8
Amounts due under reinsurance agreements				(344.3)
Income tax liabilities				(6.3)
Other operating assets and liabilities				(25.8)
Other, net				3.1
Net cash provided by operating activities				80.0
Cash flows - investing activities
Net cash used in investing activities				(296.1)
Cash flows - financing activities
Net cash provided by (used in) financing activities				132.5
Net decrease in cash				(83.6)
Cash at beginning of period			42.8	133.7
Cash at end of period		50.1		50.1
Effect of the Adoption of ASU 2018-12
Cash flows - operating activities
Net income (loss)		8.3		14.1
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net investment losses				0.0
Depreciation and intangible asset amortization				0.0
Share-based compensation expense				0.0
Loss (gain) from equity method investments, net of dividends or distributions				0.0
Changes in:
Insurance liabilities				(136.6)
Amounts due under reinsurance agreements				33.9
Income tax liabilities				99.3
Other operating assets and liabilities				(10.4)
Other, net				(0.3)
Net cash provided by operating activities				0.0
Cash flows - investing activities
Net cash used in investing activities				0.0
Cash flows - financing activities
Net cash provided by (used in) financing activities				0.0
Net decrease in cash				0.0
Cash at beginning of period			$ 0.0	0.0
Cash at end of period		$ 0.0		$ 0.0