Schedule of Effect of Change in Discount Rate Assumptions on the Liability for Future Policy Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Schedule of Effect of Change in Discount Rate Assumptions on the Liability for Future Policy Benefits [Roll Forward]
OCI, Liability for Future Policy Benefit, Gain (Loss), after Reclassification Adjustment and Tax	$ 260.1	$ 3,371.4	$ (313.8)	$ 7,029.5
OCI, Liability for Future Policy Benefit, Gain (Loss), after REclassification Adjustment, Tax	76.1	903.5	(76.8)	1,886.3
Future Policy Benefits, Before Reinsurance [Member]
Schedule of Effect of Change in Discount Rate Assumptions on the Liability for Future Policy Benefits [Roll Forward]
AOCI, Liability for Future Policy Benefit, before Tax	(27.1)	(2,277.5)	(27.1)	(2,277.5)	$ (437.9)	$ 445.0	$ (7,168.8)	$ (12,565.6)
OCI, Liability for Future Policy Benefit, Gain (Loss), after Reclassification Adjustment, before Tax	410.8	4,891.3	(472.1)	10,288.1
Reinsurance Recoverable
Schedule of Effect of Change in Discount Rate Assumptions on the Liability for Future Policy Benefits [Roll Forward]
AOCI, Liability for Future Policy Benefit, before Tax	(666.9)	(379.8)	(666.9)	(379.8)	(592.3)	(748.4)	236.6	992.5
OCI, Liability for Future Policy Benefit, Gain (Loss), after Reclassification Adjustment, before Tax	(74.6)	(616.4)	81.5	(1,372.3)
Effect of Change in Discount Rate Assumptions on the LFPB
Schedule of Effect of Change in Discount Rate Assumptions on the Liability for Future Policy Benefits [Roll Forward]
Beginning of Period Balance	(260.0)	(4,912.6)	313.9	(8,570.7)
End of Period Balance	0.1	(1,541.2)	0.1	(1,541.2)
AOCI Tax, Attributable to Parent	$ 694.1	$ 1,116.1	$ 694.1	$ 1,116.1	$ 770.2	$ 617.3	$ 2,019.6	$ 3,002.4