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Commitments, Contingencies, Guarantees and Others - Other Contingencies (Details) - FDIC Special Assessment - USD ($) $ in Millions | 6 Months Ended | 11 Months Ended |
--- | --- | --- | ---
Jun. 30, 2025 | Sep. 30, 2024 | Jul. 08, 2025
Loss Contingencies [Line Items] |  |  |
Operating expenses | $ 325 | $ 289 |
Subsequent Event |  |  |
Loss Contingencies [Line Items] |  |  |
Special assessment fees |  |  | $ 200

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