Loans (Summary of Recorded Investments of Modifications) (Details) - Commercial Loan - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment related to modifications qualifying as TDRs that occurred during the quarters	$ 51.4	$ 10.0
Recorded investment at the time of default of TDRs that experienced a payment default (payment default is one missed payment) during the quarters and for which the payment default occurred within one year of the modification	$ 0.7	$ 0.8

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