STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Change in Net Unrealized Gain on Securities Before Adjustment, Tax Expense (Benefit)	$ (346.9)	$ 250.2	$ 757.0
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance, Tax Expense (Benefit)	316.8	(138.2)	(511.7)
Change in Net Gain on Hedges, Tax Benefit	(9.8)	(23.8)	(17.0)
Change in Foreign Currency Translation Adjustment, Tax Expense (Benefit)	4.2	(4.3)	0.2
Change in Unrecognized Pension and Postretirement Benefit Costs, Tax Expense (Benefit)	$ 42.1	$ (34.8)	$ (9.3)