Other Real Estate Owned (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance	$ 17.5	$ 2.2	$ 2.0	$ 2.5
Acquired through acquisition	0.0	0.0	15.8	0.0
Additions	0.1	0.0	0.1	0.3
Dispositions	(0.8)	(0.2)	(1.1)	(0.8)
Ending balance	16.8	$ 2.0	16.8	$ 2.0
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