v3.20.4
Loans (Narrative) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Purchased loans $ 1,600 $ 1,600
Federal Reserve Bank [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans Pledged for Federal Reserve Bank Debt 17,600  
Federal Home Loan Bank (FHLB) [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Loans Pledged for Federal Home Loan Bank Debt $ 20,800