Loans and Leases - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases net of unearned income	$ 758,000,000	$ 942,000,000
Unamortized premiums and discounts, deferred loan fees and costs, and fair value adjustments	73,000,000	45,000,000
Direct Financing Leases	3,000,000,000	2,900,000,000
Leveraged leases	1,300,000,000	1,700,000,000
Leveraged leases, pre-tax income (loss)	37,000,000	33,000,000
Leveraged leases, tax expense (benefit)	(6,000,000)	10,000,000
Minimum future lease payments receivable - 2013	612,000,000
Minimum future lease payments receivable - 2014	593,000,000
Minimum future lease payments receivable - 2015	472,000,000
Minimum future lease payments receivable - 2016	389,000,000
Minimum future lease payments receivable - 2017	312,000,000
Impairment of Long-Lived Assets Held-for-use	(21,000,000)
Loans pledged at the FHLB	12.7	11.2
Loans pledged at the FRB	30.9	26.8
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impairment of Long-Lived Assets Held-for-use	$ 9,000,000	$ 4,000,000