Investment Securities - Investments In Private Equity Funds Subject to Lock-Up Periods (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt and Equity Securities, FV-NI [Line Items]
1 – 3 years	$ 57.2
3 – 5 years	8.0
5 – 10 years	161.7
>10 years	24.3
Total	2,958.5	$ 2,150.2
Private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Total	$ 251.2