Securities Sold Under Agreements To Repurchase (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Securities sold under agreements to repurchase average	$ 455.0	$ 370.0	$ 299.6
Securities sold under agreements to repurchase maximum outstanding	$ 537.6	$ 398.4	$ 336.8