INVESTMENT SECURITIES - Realized and Unrealized Gain (Loss) on Securities (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Investments, Debt and Equity Securities [Abstract] | ||||
| Net unrealized gains (losses) for equity securities with readily determinable fair value (RDFV) | $ 116 | $ 9 | $ (129) | $ 19 |
| Proceeds from debt/equity securities sales and redemptions | 859 | 1,229 | 3,023 | 2,453 |
| Gross realized gains on debt securities | 11 | 11 | 42 | 21 |
| Gross realized losses and impairments on debt securities | $ (15) | $ (12) | $ (54) | $ (29) |