COMMITMENTS AND CONTINGENT LIABILITIES - Commitments to Extend Credit (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Commercial and industrial | ||
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
| Contract amount represents credit risk | $ 58,865 | $ 47,736 |
| Consumer loan portfolio | ||
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
| Contract amount represents credit risk | 24,273 | 21,659 |
| Commercial real estate | ||
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
| Contract amount represents credit risk | 5,721 | 4,036 |
| Standby letters of credit and guarantees on industrial revenue bonds | ||
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
| Contract amount represents credit risk | $ 1,977 | $ 895 |