CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 370.4	$ 182.9	$ 623.9	$ 335.9
Other Comprehensive Income (Loss)
Change in Net Unrealized Gain (Loss) on Securities Before Adjustment (net of tax expense (benefit) of $(721.3); $226.9; $(1,496.4); $(207.3))	(2,681.1)	858.8	(5,574.9)	(787.2)
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance (net of tax expense (benefit) of $420.5; $(165.8); $957.4; $166.0)	1,550.1	(625.6)	3,547.8	630.9
Change in Net Gain on Hedges (net of tax benefit of $1.6; $—; $4.5; $5.4)	(5.0)	0.4	(15.4)	(20.3)
Change in Foreign Currency Translation Adjustment (net of tax expense (benefit) of $5.3; $(0.2); $6.1; $1.6)	(61.1)	9.3	(93.0)	16.6
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense of $2.0; $1.2; $2.9; $2.4)	(5.0)	(4.1)	(9.2)	(7.9)
Net Other Comprehensive Income (Loss)	(1,192.1)	247.0	(2,126.3)	(152.1)
Comprehensive Income (Loss)	$ (821.7)	$ 429.9	$ (1,502.4)	$ 183.8