Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Income (Loss)	$ 70.2	$ (80.1)
Other Comprehensive Income Before Income Taxes
Change in Net Unrecognized Postretirement Benefit Costs	(0.9)	(0.5)
Change in Discount Rate on Future Life Policyholder Benefits	141.1	(109.8)
Other Comprehensive Income Before Income Taxes	32.5	76.9
Other Comprehensive Income Tax Expense	(6.7)	(16.7)
Other Comprehensive Income, Net of Taxes	25.8	60.2
Total Comprehensive Income (Loss)	96.0	(19.9)
Less: Total Comprehensive Loss attributable to Noncontrolling Interest	(1.1)	0.0
Total Comprehensive Income (Loss)	97.1	(19.9)
No Credit Losses Recognized in Condensed Consolidated Statements of Income (Loss)
Other Comprehensive Income Before Income Taxes
Changes in Net Unrealized Holding (Losses) Gains on Investment Securities with:	(109.0)	187.2
Credit Losses Recognized in Condensed Consolidated Statements of Income (Loss)
Other Comprehensive Income Before Income Taxes
Changes in Net Unrealized Holding (Losses) Gains on Investment Securities with:	$ 1.3	$ 0.0