Mortgage Loans by Property Type and Geographic Region (Details) - USD ($) $ in Millions		Dec. 31, 2025	Dec. 31, 2024
Mortgage Loans on Real Estate
Mortgage Loans	[1]	$ 2,109.5	$ 2,224.5
Percent of Total	[1]	100.00%	100.00%
New England
Mortgage Loans on Real Estate
Mortgage Loans		$ 49.9	$ 52.6
Percent of Total		2.40%	2.40%
Mid-Atlantic
Mortgage Loans on Real Estate
Mortgage Loans		$ 159.9	$ 167.2
Percent of Total		7.60%	7.50%
East North Central
Mortgage Loans on Real Estate
Mortgage Loans		$ 275.3	$ 297.2
Percent of Total		13.10%	13.40%
West North Central
Mortgage Loans on Real Estate
Mortgage Loans		$ 135.9	$ 151.1
Percent of Total		6.40%	6.80%
South Atlantic
Mortgage Loans on Real Estate
Mortgage Loans		$ 497.2	$ 532.5
Percent of Total		23.50%	23.90%
East South Central
Mortgage Loans on Real Estate
Mortgage Loans		$ 96.7	$ 95.1
Percent of Total		4.60%	4.30%
West South Central
Mortgage Loans on Real Estate
Mortgage Loans		$ 190.5	$ 193.6
Percent of Total		9.00%	8.70%
Mountain
Mortgage Loans on Real Estate
Mortgage Loans		$ 255.3	$ 278.7
Percent of Total		12.10%	12.50%
Pacific
Mortgage Loans on Real Estate
Mortgage Loans		$ 448.8	$ 456.5
Percent of Total		21.30%	20.50%
Apartment
Mortgage Loans on Real Estate
Mortgage Loans		$ 642.5	$ 658.2
Percent of Total		30.50%	29.60%
Industrial
Mortgage Loans on Real Estate
Mortgage Loans		$ 659.0	$ 690.4
Percent of Total		31.20%	31.00%
Office
Mortgage Loans on Real Estate
Mortgage Loans		$ 313.3	$ 338.4
Percent of Total		14.90%	15.20%
Retail
Mortgage Loans on Real Estate
Mortgage Loans		$ 467.0	$ 496.2
Percent of Total		22.10%	22.30%
Other Property
Mortgage Loans on Real Estate
Mortgage Loans		$ 27.7	$ 41.3
Percent of Total		1.30%	1.90%

[1] Loan-to-Value Ratio utilizes the most recent internal valuation of the property