Concentrations of Credit Risk - Commercial Real Estate Loans (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Commercial Mortgages
TOTAL LOANS	$ 47,617.0	$ 42,893.3
Mortgages
Commercial Mortgages
Office	1,035.1	1,054.0
Apartment/ Multi-family	1,633.9	1,392.7
Retail	620.9	572.2
Industrial/ Warehouse	687.1	596.2
Other	575.3	548.0
TOTAL LOANS	4,552.3	4,163.1
Commercial Real Estate
Commercial Mortgages
TOTAL LOANS	5,134.2	4,773.0
Construction, Acquisition and Development Loans	$ 581.9	$ 609.9