Loans and Leases - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized premiums and discounts, deferred loan fees and costs, and fair value adjustments	$ 111,000,000	$ 73,000,000
Direct Financing Leases	3,000,000,000	3,000,000,000
Leveraged leases	1,300,000,000	1,300,000,000
Leveraged leases, pre-tax income (loss)	25,000,000	37,000,000
Leveraged leases, tax expense (benefit)	(9,000,000)	6,000,000
Minimum future lease payments receivable - 2014	664,000,000
Minimum future lease payments receivable - 2015	591,000,000
Minimum future lease payments receivable - 2016	505,000,000
Minimum future lease payments receivable - 2017	389,000,000
Minimum future lease payments receivable - 2018	289,000,000
Residual value write-downs related to leases	(6,000,000)	(21,000,000)
Loans and leases net of unearned income	700,000,000	758,000,000
Loans pledged at the FHLB	10,900,000,000	12,700,000,000
Loans pledged at the FRB	33,500,000,000	30,900,000,000
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residual value write-downs related to leases	$ 13,000,000	$ 9,000,000