Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Entity Information
Unused credit card lines		$ 2,539.8
Off-Balance Sheet, Credit Loss, Liability	$ 16.2	3.8	$ 3.7
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	(68.4)	14.7	$ (55.5)
Cumulative Effect, Period of Adoption, Adjusted Balance
Entity Information
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	12.4	0.1
Unused Credit Card Lines
Entity Information
Credit extension commitments	827.6	681.6
Unused credit card lines	5,173.3
Standby Letters of Credit
Entity Information
Credit extension commitments	$ 93.8	$ 57.5