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Commitments, Contingencies, Guarantees and Others - Unfunded Lending Commitments: Contractual Amount and Carrying Value (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
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Loss Contingencies [Line Items] |  |
Total unfunded lending commitments, contractual amount | $ 723,800 | $ 458,054
Off-balance sheet lending commitment, carrying value | 100 | 103
Credit Card: |  |
Loss Contingencies [Line Items] |  |
Credit car lines, contractual amount | 675,646 | 411,603
Other loan commitments |  |
Loss Contingencies [Line Items] |  |
Credit car lines, contractual amount | 46,774 | 45,145
Off-balance sheet lending commitment, carrying value | 71 | 73
Advised line of credit | 6,200 | 6,000
Letter of credit |  |
Loss Contingencies [Line Items] |  |
Standby letters of credit and commercial letters of credit, contractual amount | 1,380 | 1,306
Off-balance sheet lending commitment, carrying value | $ 29 | $ 30

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