SECURITIES - Narrative (Details) - USD ($) |
Mar. 31, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Schedule of Available-for-sale and Held-to-maturity Securities [Line Items] | ||
| Accrued interest receivable on debt securities | $ 138,000,000 | $ 139,000,000 |
| Held-to-maturity, zero expected credit loss, percent of portfolio | 96.00% | |
| Allowance for credit loss recognized | $ 0 | |
| Securities Sold under Agreements to Repurchase | ||
| Schedule of Available-for-sale and Held-to-maturity Securities [Line Items] | ||
| Debt securities at fair value | $ 3,700,000,000 | $ 3,400,000,000 |