Loans and Leases - Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized premiums and discounts, deferred loan fees and costs, and fair value adjustments	$ 169,000,000	$ 111,000,000
Unearned Income	665,000,000	700,000,000
Loans pledged at the FHLB	11,100,000,000	10,900,000,000
Loans pledged at the FRB	33,900,000,000	33,500,000,000
Direct Financing Leases	2,800,000,000	2,700,000,000
Leveraged leases	874,000,000	881,000,000
Leveraged leases, pre-tax income (loss)	25,000,000	25,000,000
Leveraged leases, tax expense (benefit)	9,000,000	9,000,000
Minimum future lease payments receivable - 2015	681,000,000
Minimum future lease payments receivable - 2016	625,000,000
Minimum future lease payments receivable - 2017	501,000,000
Minimum future lease payments receivable - 2018	405,000,000
Minimum future lease payments receivable - 2019	329,000,000
Residual value write-downs related to leases	$ 4,000,000	$ 13,000,000

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The net investment in direct financing leases as of the balance sheet date consisting of: (a) minimum lease payments due on direct financing leases, (b) unguaranteed residual value, and (c) any unamortized initial direct costs; less: (i) executory costs, (ii) unearned income, and (iii) the accumulated allowance for uncollectible minimum lease payments.

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-Publisher FASB

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Total carrying amount as of the balance sheet date of unearned revenue or income, not otherwise specified in the taxonomy, which is expected to be taken into income in future periods and obligations not separately disclosed in the balance sheet (other liabilities).

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The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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- Definition

The net investment in arrangements meeting the criteria to be classified as leveraged excluding deferred taxes.

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- Definition

Pretax lease income allocated in proportionate amounts from unearned income.

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The tax effect from the current year income from arrangements meeting the criteria for classification as a leveraged lease.

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- Definition

Future rental payments receivable within one year of the balance sheet date under an operating lease.

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Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

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Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

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Future rental payments receivable within the third year from the balance sheet date under an operating lease.

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Future rental payments receivable within the second year from the balance sheet date under an operating lease.

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- Definition

The sum of the carrying amounts, as of the date of the latest financial statement presented, of loans receivable which are owned but transferred to serve as collateral for the payment of related debt obligations, primarily secured borrowings and repurchase agreements, and for which the transferees are not permitted to sell or re-pledge them to an unrelated party.

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The carrying amount, as of the date of the latest financial statement presented, of loans receivable which are owned but transferred to serve as collateral for the payment of FHLB debt obligations, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

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- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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