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Fair Value Measurements - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Weighted-average discount rates for fair value estimations | 50.00% |  |
Residential Mortgage Loans |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Capitalized servicing rights, valuation allowance | $ 0 | $ 0 | $ 0
Minimum |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Discount rates for fair value estimations | 10.00% |  |
Maximum |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Discount rates for fair value estimations | 90.00% |  |
Level 3 |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves | $ 287,000,000 | $ 381,000,000 | 191,000,000
Level 3 | Commitment Expiration |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Held-for-sale measurement input (as a percent) | 0.06 | 0.05 |
Level 3 | Residential Mortgage Loans |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Capitalized servicing rights, valuation allowance | $ 0 | $ 0 |
Valuation Allowances Recorded |  |  | 24,000,000
Nonrecurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Loans measured at fair value on nonrecurring basis | 847,000,000 | 923,000,000 | 853,000,000
Nonrecurring | Level 2 |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Loans measured at fair value on nonrecurring basis | 187,000,000 | 234,000,000 | 329,000,000
Nonrecurring | Level 3 |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Loans measured at fair value on nonrecurring basis | $ 660,000,000 | $ 689,000,000 | $ 524,000,000

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