Fair Value - Unfunded Loan and Lease Commitments and Letters of Credit (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Unfunded loan and lease commitments and letters of credit
Aggregate commitments to extend credit, standby letters of credit and commercial letters of credit	$ 7,000.0	$ 6,700.0
Fair Value, Inputs, Level 3 [Member]
Unfunded loan and lease commitments and letters of credit
Estimated fair value of unfunded loan and lease commitments and letters of credit	$ 48.5	$ 44.3