Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2015
Stockholders Equity [Line Items]
Minimum Tier 1 Ratio to be well capitalized	8.00%
Minimum Common Equity Tier 1 Ratio to be well capitalized	6.50%
Minimum Total Capital Ratio to be well capitalized	10.00%
Minimum Leverage Ratio to be well capitalized	5.00%
2015 [Member]
Stockholders Equity [Line Items]
Implementation of the deductions and other adjustments to CET1	4 years
Implementation of the deductions and other adjustments to CET1, Percentage	40.00%
After 2015 [Member]
Stockholders Equity [Line Items]
Implementation of the deductions and other adjustments to CET1, Additional Percentage	20.00%
2016 [Member]
Stockholders Equity [Line Items]
Implementation of the capital conservation buffer, Percentage	0.625%
Capital conservation buffer implementation phase-out 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

Common equity tier one risk based capital required to be well capitalized to risk weighted assets.

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- Definition

Implementation of deductions and other adjustments to CET one.

+ References

No definition available.

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- Definition

Implementation of deductions and other adjustments to CET one additional Percentage.

+ References

No definition available.

+ Details

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- Definition

Implementation of deductions and other adjustments to CET one percentage.

+ References

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- Definition

Quantitative limit for trust preferred securities to be included in tier one capital.

+ References

No definition available.

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- Definition

Tier one capital conservation buffer maximum level.

+ References

No definition available.

+ Details

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- Definition

Tier one capital conservation buffer to risk weighted assets required under regulatory.

+ References

No definition available.

+ Details

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- Definition

Tier one risk based capital conservation buffer initial requirements phasing duration.

+ References

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- Definition

The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

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- Definition

The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

+ References

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- Definition

The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

+ References

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