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Mortgage Banking Activity - Residential Mortgage Loans (Details) - USD ($) $ in Millions | 9 Months Ended | 12 Months Ended
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Sep. 30, 2025 | Dec. 31, 2024
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward] |  |
Balance at beginning of period | $ 551 |
Balance at end of period | 501 | $ 551
Mortgage loans |  |
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward] |  |
Balance at beginning of period | 81 | 62
Originations and purchases | 853 | 951
Sales, net of gains | (800) | (932)
Balance at end of period | $ 134 | $ 81

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- Definition Financing Receivable Held-for-sale, Reconciliation to Cash Flow, Originations and Purchases + References No definition available. + Details
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- Definition Amount of gain (loss) on sale of financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481326/860-20-50-5 + Details
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- Definition Amount, after valuation allowance, of financing receivable held for sale and not part of disposal group. Excludes loan covered under loss sharing agreement and loan classified as investment in debt security. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Details
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