Concentrations of Credit Risk (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Concentration Risk [Line Items]
Total Residential Real Estate	$ 6,327.1	$ 6,413.5
Florida
Concentration Risk [Line Items]
Total Residential Real Estate	1,648.1	1,603.2
California
Concentration Risk [Line Items]
Total Residential Real Estate	1,463.8	1,508.1
Illinois
Concentration Risk [Line Items]
Total Residential Real Estate	640.3	686.9
New York
Concentration Risk [Line Items]
Total Residential Real Estate	505.4	498.7
Colorado
Concentration Risk [Line Items]
Total Residential Real Estate	344.1	364.2
Texas
Concentration Risk [Line Items]
Total Residential Real Estate	318.7	312.4
All other
Concentration Risk [Line Items]
Total Residential Real Estate	$ 1,406.7	$ 1,440.0