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Investment Securities - Additional Information (Detail) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2024 USD ($) Security | Mar. 31, 2023 USD ($) | Dec. 31, 2023 USD ($)
Summary of Investment Holdings [Line Items] |  |  |
Gross realized gains(loss) on sale of investment securities | $ 0 | $ 0 |
Gains (losses) on equity securities | $ 2,000,000 |  |
Number of debt securities with aggregate gross unrealized losses | Security | 4,088 |  |
Unrealized losses on individual debt securities | $ (1,500,000,000) |  |
Cost method equity securities | 928,000,000 |  |
Investment securities pledged to secure debt carrying value | 9,600,000,000 |  | $ 8,200,000,000
Carrying value of investment securities pledged related to repurchase transactions | 357,000,000 |  | 393,000,000
Available-for-Sale Securities [Member] |  |  |
Summary of Investment Holdings [Line Items] |  |  |
Allowance for credit losses | $ 0 |  | $ 0

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