Other Operating Expense (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other Income and Expenses [Abstract]
Business Promotion		$ 74.8	$ 76.7	$ 65.5
Staff Related		35.0	34.6	33.9
FDIC Insurance Premiums		112.0	17.8	14.6
Charitable Contributions		15.6	19.4	18.0
Other Expenses		235.5	210.8	167.1
Total Other Operating Expense		472.9	359.3	299.1
Noninterest expense		$ 5,284.2	$ 4,982.9	$ 4,535.9
Federal deposit insurance corporation premium expense, special assessment	$ 84.6