Schedule of Participating Mortgage Loans by Internal Credit Rating and Loan to Value (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Mortgage Loans on Real Estate
Mortgage Loans	$ 2,224.5	$ 2,318.2
Percent of Total	100.00%	100.00%
Loan to Value Ratio Below or Equal to 65 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 1,639.6	$ 1,409.9
Percent of Total	73.80%	60.80%
Loan To Value Ratio Above 65 To 75 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 367.6	$ 707.0
Percent of Total	16.50%	30.50%
Loan To Value Ratio Above 75 To 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 152.3	$ 136.5
Percent of Total	6.80%	5.90%
Loan To Value Ratio Above 85 Percent
Mortgage Loans on Real Estate
Mortgage Loans	$ 65.0	$ 64.8
Percent of Total	2.90%	2.80%
AA Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 117.8	$ 85.2
Percent of Total	5.30%	3.70%
A Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 1,099.1	$ 942.5
Percent of Total	49.40%	40.60%
BBB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 915.5	$ 1,249.5
Percent of Total	41.20%	53.90%
BB Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 85.0	$ 41.0
Percent of Total	3.80%	1.80%
B Credit Rating
Mortgage Loans on Real Estate
Mortgage Loans	$ 7.1	$ 0.0
Percent of Total	0.30%	0.00%