Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Mortgage Loans on Real Estate
Mortgage Loans	$ 2,435.4	$ 2,560.4
Percent of Total	100.00%	100.00%
Loan to Value Ratio Below or Equal to 65 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 1,389.6	$ 1,346.1
Percent of Total	57.00%	52.60%
Loan To Value Ratio Above 65 To 75 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 937.2	$ 1,076.8
Percent of Total	38.50%	42.00%
Loan To Value Ratio Above 75 To 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 75.0	$ 114.9
Percent of Total	3.10%	4.50%
Loan To Value Ratio Above 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 33.6	$ 22.6
Percent of Total	1.40%	0.90%
Total
Mortgage Loans on Real Estate
Percent of Total	100.00%	100.00%
AA Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 92.3	$ 27.3
Percent of Total	3.80%	1.10%
A Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 843.9	$ 709.6
Percent of Total	34.60%	27.70%
BBB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 1,458.0	$ 1,802.6
Percent of Total	59.90%	70.40%
BB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 41.2	$ 20.9
Percent of Total	1.70%	0.80%
Total
Mortgage Loans on Real Estate
Percent of Total	100.00%	100.00%