Composition of loans held-in-portfolio-noncovered loans (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	$ 24,682,139		$ 24,951,299
Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	719,508		786,765
Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	7,016,449		6,691,414
Finance Leases Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	537,917		548,706
Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	509,829		648,409
Consumer Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	3,964,445		3,789,936
Non-covered loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	20,665,809	[1]	20,602,596	[1]
Non-covered loans | Commercial Multi Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	871,924		808,933
Non-covered loans | Commercial Real Estate Non Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	2,625,014		2,665,499
Non-covered loans | Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	2,636,039		2,817,266
Non-covered loans | Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	3,469,838		3,681,629
Non-covered loans | Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	249,743		239,939
Non-covered loans | Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	5,899,973		5,518,460
Non-covered loans | Finance Leases Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	537,917		548,706
Non-covered loans | Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	509,829	[2]	648,409	[2]
Non-covered loans | Consumer Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	3,865,532		3,673,755
Non-covered loans | Consumer Portfolio Segment Member | Consumer Credit Card Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	1,209,868		1,230,029
Non-covered loans | Consumer Portfolio Segment Member | Home Equity Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	525,093		557,894
Non-covered loans | Consumer Portfolio Segment Member | Personal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	1,352,993		1,130,593
Non-covered loans | Consumer Portfolio Segment Member | Consumer Loans Auto Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	539,899		518,476
Non-covered loans | Consumer Portfolio Segment Member | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-in-portfolio	$ 237,679		$ 236,763

[1] Non-covered loans held-in-portfolio at June 30, 2012 are net of $98 million in unearned income and exclude $365 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.