COMMITMENTS AND CONTINGENCIES - Schedule of Fair Value, Off-balance Sheet Risks (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Financing assets (excluding leases) | ||
| Other Commitments [Line Items] | ||
| Credit related commitments | $ 52,221 | $ 51,726 |
| Financial standby letters of credit | ||
| Other Commitments [Line Items] | ||
| Credit related commitments | 2,903 | 2,583 |
| Other letters of credit | ||
| Other Commitments [Line Items] | ||
| Credit related commitments | 210 | 227 |
| Deferred Purchase Agreements | ||
| Other Commitments [Line Items] | ||
| Credit related commitments | 1,852 | 1,723 |
| Purchase and Funding Commitments | ||
| Other Commitments [Line Items] | ||
| Credit related commitments | $ 57 | $ 102 |