Composition of loans held-in-portfolio-noncovered loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	$ 24,657,720		$ 24,951,299
Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	651,554		786,765
Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	7,129,273		6,691,414
Finance Leases Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	538,014		548,706
Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	465,848		648,409
Consumer Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	3,920,038		3,789,936
Non Covered Under Loss Sharing Agreements With F D I C [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	20,753,853	[1]	20,602,596	[1]
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Multi Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	932,434		808,933
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Real Estate Non Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	2,643,533		2,665,499
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	2,640,074		2,817,266
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	3,412,590		3,681,629
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	258,453		239,939
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	6,022,422		5,518,460
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Finance Leases Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	538,014		548,706
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	465,848	[2]	648,409	[2]
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	3,840,485		3,673,755
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member | Consumer Credit Card Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	1,195,413		1,230,029
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member | Home Equity Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	506,206		557,894
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member | Personal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	1,357,441		1,130,593
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member | Consumer Loans Auto Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	546,481		518,476
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member | Consumer Other Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	$ 234,944		$ 236,763

[1] Non-covered loans held-in-portfolio at September 30, 2012 are net of $97 million in unearned income and exclude $337 million in loans held-for-sale. (December 31, 2011 - $101 million in unearned income and $363 million in loans held-for-sale.)

[2] The legacy portfolio is comprised of commercial loans, construction loans and lease financings related to certain lending products exited by the Corporation as part of restructuring efforts carried out in prior years at the BPNA reportable segment.