Investment Securities - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Fair value of securities pledged	$ 8,400	$ 10,900
Fair value of securities pledged as collateral where counterparty has right to repledge or resell	269	$ 2,100
Held-to-maturity investment securities transferred to available-for-sale	43,600
Unrealized gains and losses on held-to-maturity investment securities transferred to available-for-sale	$ 141

Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions where counterparty has the right to re-pledge such.

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- References

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification.

+ References

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Held-to-maturity investment securities transferred to available-for-sale.

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