Securities - Narrative (Detail) - USD ($)	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, allowance for credit losses	$ 0		$ 0
Securities held-to-maturity, allowance for credit losses	0		0
Securities held-to-maturity, past due	15,294,000,000		15,076,000,000
Securities held-to-maturity, nonaccrual	0		0
Debt Securities, Available-for-Sale, Realized Loss	0	$ 0
Equity securities without readily determinable fair values, impairment loss adjustment	4,000,000	$ 4,000,000
Past Due
Debt Securities, Available-for-sale [Line Items]
Securities held-to-maturity, past due	0		0
Other assets
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank stock	95,000,000		95,000,000
Federal Reserve Bank stock	$ 438,000,000		$ 438,000,000

Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Amount excluding accrued interest, of investment in debt security measured at amortized cost (held-to-maturity) on nonaccrual status.

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Amount of impairment loss on investment in equity security without readily determinable fair value.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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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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