Variable Interest Entities Affordable Housing Tax Credit Investments (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Low Income Housing Tax Credit Investments [Member] - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Variable Interest Entity [Line Items] | ||
| Affordable housing tax credit investments included in other assets | $ 932 | $ 1,021 |
| Unfunded affordable housing tax credit commitments included in other liabilities | 213 | 289 |
| Loans and letters of credit commitments | 265 | 329 |
| Funded portion of loans and letters of credit commitments | $ 157 | $ 166 |