Commitments - Extensions of Credit (Details) - USD ($) $ in Billions |
Mar. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Extended lines of credit | ||
| Commitments, guarantees: | ||
| Unused amounts in lines of credit to third-party entities and commitments for future financing to clients | $ 1.6 | $ 2.1 |
| Financing for client purchase agreements | ||
| Commitments, guarantees: | ||
| Unused amounts in lines of credit to third-party entities and commitments for future financing to clients | $ 4.7 | $ 5.2 |