Loan Sale and Servicing Activities and Variable Interest Entities Loan Sale and Servicing Activities and Variable Interest Entities (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Low Income Housing Tax Credit Investments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortization, tax credits, and other tax benefits recognized low income housing tax credit investments (less than)	$ 100.0	$ 100.0