CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income	$ 153.0	$ 161.0
Other Comprehensive Income (Loss)
Change in Net Unrealized Gain on Securities Before Adjustment (net of tax benefit of $434.2; $436.5)	(1,646.0)	(1,666.7)
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance (net of tax expense of $331.8; $380.8)	1,256.5	1,446.1
Change in Net Gain on Hedges (net of tax expense (benefit) of $(5.4); $6.6)	(20.7)	22.8
Change in Foreign Currency Translation Adjustment (net of tax expense of $1.8; $2.1)	7.3	(63.6)
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense of $1.2; $1.9)	(3.8)	(7.0)
Total Other Comprehensive Loss	(399.1)	(254.4)
Comprehensive Loss	$ (246.1)	$ (93.4)