FDIC loss share - Additional Information (Detail) (USD $)	6 Months Ended	3 Months Ended							3 Months Ended
	Jun. 30, 2013 D	Jun. 30, 2013 Payment Percentage True Up Payment [Member]	Jun. 30, 2013 Intrinsic Loss Estimate Trueup Payment [Member]	Jun. 30, 2013 Asset Discount Trueup Payment [Member]	Jun. 30, 2013 Cumulative Shared Loss Payments Trueup Payment [Member]	Jun. 30, 2013 Servicing Percentage Trueup Payment [Member]	Jun. 30, 2013 Banco Popular De Puerto Rico [Member]	Jun. 30, 2013 Banco Popular De Puerto Rico [Member] Other Consumer And Commercial Loans [Member]	Jun. 30, 2013 Federal Deposit Insurance Corporation [Member]	Jun. 30, 2013 Federal Deposit Insurance Corporation [Member] Residential Mortgage	Jun. 30, 2013 Federal Deposit Insurance Corporation [Member] Other Consumer And Commercial Loans [Member]
Business Acquisition, Contingent Consideration [Line Items]
Loss Sharing Term										10	5
Loss Share Agreements Reimbursement Term								8
True Up Payment Term	45
Percent Calculation Intrinsic Loss Estimate			$ 925,000,000
Calculation Percent Asset Discount Per Bid	1,100,000,000
Intrinsic Loss Estimate	$ 4,600,000,000
Servicing Amount Period Trueup Payment	twelve-month period
Fixed Percentage True Up Payment		50.00%	20.00%	25.00%	25.00%	1.00%
Loss Sharing Agreement Allocation Percentage							80.00%		80.00%