Loans & Leases (Loans and Leases - Additional Information) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Schedule Of Accounts Notes Loans And Financing Receivable [Table][Abstract]
Unamortized premiums and discounts, deferred loan fees and costs, and fair value adjustments	$ 240	$ 220
Unearned Income	503	624
Loans pledged at the FHLB	13,100	11,900
Loans pledged at the FRB	40,000	33,700
Direct Financing Leases	3,300	3,100
Leveraged leases	701	801
Leveraged leases, pre-tax income (loss)	38	27
Gain On Early Termination Of Leverage Leases	16	7
Leveraged leases, tax expense (benefit)	10	1
Minimum future lease payments receivable - 2016	813
Minimum future lease payments receivable - 2017	716
Minimum future lease payments receivable - 2018	611
Minimum future lease payments receivable - 2019	482
Minimum future lease payments receivable - 2020	361
Residual value write-downs related to commercial leases	$ 1	$ 8

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Schedule itemizing specific types of trade accounts and notes receivable, and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables.

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

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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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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 third year from the balance sheet date under an operating lease.

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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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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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