Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Entity Information [Line Items]
Off-Balance Sheet, Credit Loss, Liability	$ 9.7	$ 3.2	$ 9.7	$ 3.2	$ 6.2	$ 3.8	$ 3.4	$ 3.7
Provision for (reversal of) credit loss expense	(4.6)	(0.2)	(60.2)	4.6
Credit Extension Commitments	5,011.0		5,011.0			2,539.8
Unused Credit Card Lines
Entity Information [Line Items]
Credit Extension Commitments	814.9		814.9			681.6
Standby Letter of Credit
Entity Information [Line Items]
Credit Extension Commitments	92.4		92.4			$ 57.5
Cumulative effect, period of adoption, adjusted balance
Entity Information [Line Items]
Provision for (reversal of) credit loss expense	$ 3.5	$ (0.2)	$ 5.9	$ (0.5)