CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net Income	$ 202.0	$ 510.3	$ 953.2	$ 1,118.0
Other Comprehensive Income (Loss)
Change in Net Unrealized Loss on Securities (net of tax benefit of $313.8; $520.8; $249.2; $2,017.2)	(1,185.8)	(1,925.9)	(920.0)	(7,500.7)
Change in the Effect of Discount Rate Assumptions on the Liability for Future Policy Benefits, Net of Reinsurance (net of tax expense of $445.0; $599.4; $368.2; $2,485.7)	1,688.4	2,222.9	1,374.6	9,252.4
Change in Net Loss on Hedges (net of tax benefit of $38.9; $8.1; $44.7; $12.6)	(144.4)	(32.9)	(168.1)	(48.3)
Change in Foreign Currency Translation Adjustment (net of tax expense (benefit) of $(0.7); $5.4; $0.3; $11.5)	(55.1)	(71.5)	7.9	(164.9)
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense of $1.2; $1.1; $1.1; $4.0)	(3.9)	(5.9)	(3.3)	(15.1)
Net Other Comprehensive Income (Loss)	307.0	198.5	297.7	1,553.6
Comprehensive Income (Loss)	$ 509.0	$ 708.8	$ 1,250.9	$ 2,671.6