Note FDIC loss share asset (FDIC loss share - Additional Information) (Detail) $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($) D	Mar. 31, 2017
Business Acquisition, Contingent Consideration [Line Items]
True Up Payment Term \| D	45
Calculation Percent Asset Discount Per Bid	$ 1,100
Intrinsic Loss Estimate	$ 4,600
Servicing Amount Period Trueup Payment	twelve-month period
Fair Value Inputs Discount Rate	4.57%	5.47%
Payment Percentage True-up Payment
Business Acquisition, Contingent Consideration [Line Items]
Fixed Percentage True Up Payment	50.00%
Intrinsic Loss Estimate True-up Payment
Business Acquisition, Contingent Consideration [Line Items]
Percent Calculation Intrinsic Loss Estimate	$ 925
Fixed Percentage True Up Payment	20.00%
Asset Discount True-up Payment
Business Acquisition, Contingent Consideration [Line Items]
Fixed Percentage True Up Payment	25.00%
Cumulative Shared Loss Payments True-up Payment
Business Acquisition, Contingent Consideration [Line Items]
Fixed Percentage True Up Payment	25.00%
Servicing Percentage True-up Payment
Business Acquisition, Contingent Consideration [Line Items]
Fixed Percentage True Up Payment	1.00%
Single Family Loan
Business Acquisition, Contingent Consideration [Line Items]
Weighted Average Life Of Loan Subject To F D I C Agreement	7 years 1 month
Banco Popular de Puerto Rico
Business Acquisition, Contingent Consideration [Line Items]
Loss Sharing Agreement Allocation Percentage	80.00%

Represents 25% of the asset discount (per bid) in true-up payment obligation formula under FDIC loss sharing agreements

No definition available.

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- Definition

Pre-determined percentages in True-up Payment Obligation Formula under FDIC loss sharing agreements.

+ References

No definition available.

+ Details

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- Definition

Intrinsic loss estimate in true-up payment obligation formula under FDIC loss sharing agreements

+ References

No definition available.

+ Details

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- Definition

Loss Sharing Agreement Allocation Percentage

+ References

No definition available.

+ Details

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- Definition

Represents 20% of intrinsic loss estimate of $4.6 billion in true-up payment obligation formula under FDIC loss sharing agreements

+ References

No definition available.

+ Details

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- Definition

Period length used to calculate each servicing amount in true-up payment formula under FDIC loss sharing agreements

+ References

No definition available.

+ Details

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- Definition

Term to make true-up payment under the FDIC loss sharing agreements.

+ References

No definition available.

+ Details

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- Definition

Weighted average life of loan portfolios subject to the FDIC loss Sharing agreements.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

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- Details

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- Details

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- Details

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