Investment Securities - Investments In Private Equity Funds Subject to Lock-Up Periods (Details) - Private equity funds $ in Millions	Sep. 30, 2022 USD ($)
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	$ 185.1
1 – 3 years
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	27.5
3 – 5 years
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	19.0
5 – 10 years
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	135.4
Greater than 10 years
Debt and Equity Securities, FV-NI [Line Items]
Fair Value	$ 3.2