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Investment Securities - Additional Information (Details) - USD ($) |  |  | 3 Months Ended | 6 Months Ended
--- | --- | --- | --- | ---
Jun. 30, 2024 | Dec. 31, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |  |
Accrued interest receivable | $ 245,000,000 | $ 227,000,000 |  |  |  |
Proceeds from sale of debt securities, available-for-sale |  |  | $ 0 | $ 0 | $ 0 | $ 0
Investment securities | 40,600,000,000 | 45,100,000,000 | 40,600,000,000 |  | 40,600,000,000 |
Securities received as collateral | $ 6,000,000 | $ 16,000,000 | $ 6,000,000 |  | $ 6,000,000 |
Investment securities available for sale | Government Contracts Concentration Risk | US Treasury and Agency securities |  |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |  |
Percentage of portfolio | 96.00% | 97.00% |  |  |  |

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