Other Real Estate Owned (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance	$ 16.8	$ 2.0	$ 2.0	$ 2.5
Acquired through acquisition	0.0	0.0	15.8	0.0
Additions	0.3	0.4	0.4	0.7
Dispositions	(0.5)	(0.1)	(1.6)	(0.9)
Ending balance	16.4	$ 2.3	16.4	$ 2.3
Carrying values of foreclosed residential real estate properties	0.0		0.0
Consumer mortgage loans collateralized by residential real estate property in the process of foreclosure	$ 0.0		$ 0.0