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Investment Securities - Narrative (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2023
Marketable Securities [Abstract] |  |  |  |  |
Gains (losses) on available-for-sale securities | $ 0 | $ 0 | $ 0 | $ 0 |
Available-for-sale, accrued interest, after allowance for credit loss | 28,000,000 |  | 28,000,000 |  | $ 32,000,000
Transfers between available for sale and held to maturity debt securities | 0 | 0 | 0 | 0 |
Held-to-maturity, accrued interest, after allowance for credit loss | 3,000,000 |  | 3,000,000 |  | 3,000,000
Allowance for credit loss | 0 |  | 0 |  | 0
Carrying amount of equity investments without a readily determinable fair value | 91,000,000 |  | 91,000,000 |  | $ 89,000,000
Unrealized gains for equity investments with readily determinable fair values (prior year QTD less than) | $ 4,000,000 | $ 1,000,000 | $ 11,000,000 | $ 7,000,000 |

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