Securities - Narrative (Detail) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Dec. 31, 2024 |
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| 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 | 18,139,000,000 | 17,798,000,000 | |
| Debt securities, available-for-sale, realized loss | 0 | $ 0 | |
| Securities held-to-maturity, nonaccrual | 0 | 0 | |
| Equity securities without readily determinable fair values, impairment loss adjustment | 3,000,000 | $ 4,000,000 | |
| Total Past Due 30 Days or More | |||
| Debt Securities, Available-for-sale [Line Items] | |||
| Securities held-to-maturity | 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 | |
| X | ||||||||||
- Definition 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). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition 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). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Amount excluding accrued interest, of investment in debt security measured at amortized cost (held-to-maturity) on nonaccrual status. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of impairment loss on investment in equity security without readily determinable fair value. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition 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). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition 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). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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