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Regulatory Capital - Additional Information (Detail) $ in Billions | Sep. 30, 2025 USD ($) | Mar. 30, 2020
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Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Maximum asset value required to be maintained leverage ratio | $ 10 |
Tier 1 capital ratio of risk-weighted assets | 0.025 |
Maximum [Member] |  |
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |
Leverage ratio |  | 0.09

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- Definition Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 505 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477270/942-505-50-1 + Details
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