Loans and leases - Total Gross Loans and Leases Outstanding (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Loans
Commercial, financial, etc.	$ 16,500,202	$ 14,419,490
Real estate:
Residential	11,161,323	7,889,569
Commercial	22,333,036	20,312,648
Construction	3,772,413	4,203,324
Consumer	11,550,274	12,020,229
Total loans	65,317,248	58,845,260
Leases
Commercial	1,472,938	1,532,615
Total loans and leases	66,790,186	60,377,875
Less: unearned discount	(219,229)	(281,870)
Total loans and leases, net of unearned discount	$ 66,570,957	$ 60,096,005

Loans and Leases Receivable Consumer Installment Revolving and Home equity.

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Loans receivable gross.

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Amount before allowance of commercial leases and leveraged lease transactions where the entity is long-term creditor. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes leases covered under loss sharing agreements.

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Amount before allowance of consumer mortgage. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes subordinated loans such as home equity lines of credit and loans and leases covered under loss sharing agreements.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance of commercial construction loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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Amount before allowance of loans issued to agricultural, commercial and industrial, and financial institutions. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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Amount before allowance of mortgage loans on existing land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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