Basis of Presentation and Accounting Policies - Effects of Adoption (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Earned Premiums (Changes in Deferred Profit Liability for the Nine and Three Months Ended: 2023 - $51.6 and $15.9; 2022 - $56.8 and $19.1)	$ 1,117.8	$ 1,290.9	$ 3,465.6	$ 3,948.5
Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses (Changes in Liability for Future Policyholder Benefits for the Nine and Three Months Ended: 2023 - $8.6 and $6.1; 2022 - $21.9 and $1.6)	975.2	1,085.3	3,011.9	3,359.6
Insurance Expenses	259.0	300.5	794.4	913.0
Income Tax Benefit	44.4	13.0	87.0	64.8
Net Loss	$ (146.3)	$ (74.8)	$ (323.5)	$ (233.3)
Basic (in dollars per share)	$ (2.28)	$ (1.17)	$ (5.05)	$ (3.66)
Diluted (in dollars per share)	$ (2.28)	$ (1.17)	$ (5.05)	$ (3.66)
Deferred Policy Acquisition Costs	$ 622.2	$ 683.8	$ 622.2	$ 683.8	$ 635.6	$ 688.0
Deferred Income Tax Assets	258.5		258.5		129.0
Total Assets	12,549.3		12,549.3		13,313.6
Life and Health	3,098.1		3,098.1		3,276.2
Total Liabilities	10,188.1		10,188.1		10,643.0
Retained Earnings	982.4		982.4		1,366.4
Accumulated Other Comprehensive Loss	(473.4)		(473.4)		(514.9)
Stockholders' Equity Attributable to Parent	2,361.3		2,361.3		2,670.6
Other Comprehensive Loss Before Income Taxes	8.8	(81.6)	52.3	(218.0)
Other Comprehensive Income (Loss), Net of Taxes	7.4	(64.4)	41.5	(172.2)
Total Comprehensive Loss	$ (138.9)	(139.2)	$ (282.0)	(405.5)
Revision of Prior Period, Accounting Standards Update, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Earned Premiums (Changes in Deferred Profit Liability for the Nine and Three Months Ended: 2023 - $51.6 and $15.9; 2022 - $56.8 and $19.1)		(16.1)		(50.8)
Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses (Changes in Liability for Future Policyholder Benefits for the Nine and Three Months Ended: 2023 - $8.6 and $6.1; 2022 - $21.9 and $1.6)		(17.1)		(66.5)
Insurance Expenses		(0.8)		0.0
Income Tax Benefit		(0.4)		(3.3)
Net Loss		$ 1.4		$ 12.4
Basic (in dollars per share)		$ 0.02		$ 0.19
Diluted (in dollars per share)		$ 0.02		$ 0.19
Deferred Policy Acquisition Costs					10.0
Deferred Income Tax Assets					(60.4)
Total Assets					(50.4)
Life and Health					(277.8)
Total Liabilities					(277.8)
Retained Earnings					(13.7)
Accumulated Other Comprehensive Loss					241.1
Stockholders' Equity Attributable to Parent					227.4
Accounting Standards Update 2018-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Earned Premiums (Changes in Deferred Profit Liability for the Nine and Three Months Ended: 2023 - $51.6 and $15.9; 2022 - $56.8 and $19.1)		$ 1,307.0		$ 3,999.3
Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses (Changes in Liability for Future Policyholder Benefits for the Nine and Three Months Ended: 2023 - $8.6 and $6.1; 2022 - $21.9 and $1.6)		1,102.4		3,426.1
Insurance Expenses		301.3		913.0
Income Tax Benefit		13.4		68.1
Net Loss		$ (76.2)		$ (245.7)
Basic (in dollars per share)		$ (1.19)		$ (3.85)
Diluted (in dollars per share)		$ (1.19)		$ (3.85)
Deferred Policy Acquisition Costs					625.6
Deferred Income Tax Assets					189.4
Total Assets					13,364.0
Life and Health					3,554.0
Total Liabilities					10,920.8
Retained Earnings					1,380.1
Accumulated Other Comprehensive Loss					(756.0)
Stockholders' Equity Attributable to Parent					$ 2,443.2
Other Comprehensive Loss Before Income Taxes		$ (412.5)		$ (1,638.9)
Other Comprehensive Income (Loss), Net of Taxes		(325.8)		$ (1,294.7)
Total Comprehensive Loss		$ (402.0)