Loans Held for Sale, Loans and Allowance for Credit Losses - Summary of Loans Held for Sale by Portfolio Segment at Lower of Amortized Cost or Fair Value (Parenthetical) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Accrued interest receivable	$ 45.3	$ 44.5
Loans Held for Sale
Accounts Notes And Loans Receivable [Line Items]
Accrued interest receivable	$ 0.1	$ 0.4