CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Change in Net Unrealized Gain on Securities Before Adjustment, Tax expense (benefit)	$ (119.2)	$ 219.6
Change in the Effect of Discount Rate ASsumptions on the LIability for Future Policy Benefits, Net of Reinsurance net of tax expense (benefit)	234.1	(152.9)
Change in Net Gain on Hedges, Tax Benefit	(14.1)	4.7
Change in Foreign Currency Translation Adjustment, Tax Expense	0.3	(0.2)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	$ 9.4	$ (1.6)