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 | |