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Regulatory Capital - Additional Information (Detail) - USD ($)	Jan. 01, 2019	Dec. 31, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer risk-weighted assets	2.50%
Maximum asset value required to be maintained leverage ratio		$ 10,000,000,000
Leverage ratio		9.00%
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Leverage ratio		8.00%
Maximum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Leverage ratio		10.00%

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- Definition

Maximum Asset Value Required To Be Maintained Leverage Ratio.

+ References

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- Definition

Tier one risk based capital to risk weighted assets conservation buffer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Tier 1 Leverage Capital divided by average assets as defined in the regulations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1H
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826

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