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Stockholders' Equity - Additional Information (Detail) | 9 Months Ended
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Sep. 30, 2018 USD ($)
2016 [Member] |
Stockholders Equity [Line Items] |
Implementation of the capital conservation buffer, Percentage | 0.625%
Capital conservation buffer implementation phase-in period | 4 years
2019 [Member] |
Stockholders Equity [Line Items] |
Capital Conservation Buffer Maximum Level | 2.50%
Maximum [Member] |
Stockholders Equity [Line Items] |
Quantitative limit for trust preferred securities to be included in tier 1 capital | $ 15,000,000,000

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- Definition Tier one capital conservation buffer maximum level. + References No definition available. + Details
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