Investment Securities - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt securities, Held to maturity, Allowance for credit loss	$ 0
Asset Pledged as Collateral [Member]
Debt Securities, Available-for-sale [Line Items]
Fair value of securities pledged	19,400	$ 15,300
Asset Pledged as Collateral with Right [Member]
Debt Securities, Available-for-sale [Line Items]
Fair value of securities pledged	$ 292	$ 858

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details