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Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals) - USD ($) | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Dec. 31, 2024 | Jan. 01, 2022
Other Commitments [Line Items] |  |  |  |  |
Investment Program, Proportional Amortization Method, Elected, Impairment Loss |  |  | $ 0 | $ 0 |
Loans Repurchased Under Make Whole Requests |  |  | $ 2,800,000 | 3,200,000 |
Loans Sold To Outside Investors Loss Reimbursement Settlement Paid |  |  |  | 0 |
Make Whole Requests, Loan Origination Date, Majority |  |  | Jan. 01, 2022 |  |
Loans Sold To Outside Investors Original Amount |  |  |  |  | $ 3,800,000,000
Loans Sold To Outside Investors Remaining Outstanding Amount | $ 1,600,000,000 |  | $ 1,600,000,000 |  |
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount | 36,276,000 |  | 36,276,000 | 38,776,000 |
Financing Receivable, before Allowance for Credit Loss | 30,951,964,000 |  | 30,951,964,000 | 29,768,586,000 |
Loss on Sale of Investments |  |  |  | 0 |
Residential Mortgage [Member] |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount | 500,000 |  | 500,000 | 600,000 |
Residential Mortgage [Member] | Recourse |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 9,600,000 |  | 9,600,000 | 13,700,000 |
Residential Mortgage [Member] | Recourse | Credit Risk |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 236,200,000 |  | 236,200,000 | 133,800,000 |
Loss on Sale of Investments |  |  | 0 |  |
Affordable Housing Projects and Other [Member] |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |
Other Investments | 183,500,000 |  | 183,500,000 | 204,800,000 |
Investment Program, Proportional Amortization Method, Applied, Amortization Expense | 9,200,000 | $ 8,500,000 | 26,300,000 |  |
Investment, Proportional Amortization Method, Elected, Amount | 181,500,000 |  | 181,500,000 | 202,800,000 |
Accrued Liabilities | 26,700,000 |  | 26,700,000 | 29,700,000 |
Loan Pool CRA Investments [Member] |  |  |  |  |
Other Commitments [Line Items] |  |  |  |  |
Other Investments | $ 61,700,000 |  | $ 61,700,000 | $ 54,100,000 |

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