LHFI by Credit Quality Indicator (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 121,470	[1]	$ 122,495	[1]
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	54,048		49,538
Commercial and Industrial | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	52,292		47,683
Commercial and Industrial | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,562		1,507
Commercial and Industrial | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	194		348
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,127		5,094
Commercial Real Estate | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,564		3,845
Commercial Real Estate | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	497		961
Commercial Real Estate | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	66		288
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	713		1,240
Commercial Construction [Member] | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	506		581
Commercial Construction [Member] | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	173		369
Commercial Construction [Member] | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	34		290
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23,389	[2]	23,243	[2]
Residential Nonguaranteed [Member] | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	17,410	[2]	16,139	[2]
Residential Nonguaranteed [Member] | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,850	[2]	4,132	[2]
Residential Nonguaranteed [Member] | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,129	[2],[3]	2,972	[2],[3]
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	14,805	[2]	15,765	[2]
Home Equity | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,339	[2]	11,084	[2]
Home Equity | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,297	[2]	2,903	[2]
Home Equity | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,169	[2],[3]	1,778	[2],[3]
Residential Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	753	[2]	980	[2]
Residential Construction | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	561	[2]	661	[2]
Residential Construction | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	123	[2]	202	[2]
Residential Construction | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	69	[2],[3]	117	[2],[3]
Consumer Other Direct
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,396	[4]	2,059	[4]
Consumer Other Direct | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,980	[4]	1,614	[4]
Consumer Other Direct | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	350	[4]	359	[4]
Consumer Other Direct | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	66	[3],[4]	86	[3],[4]
Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,998	[4]	10,165	[4]
Consumer Indirect | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,300	[4]	7,397	[4]
Consumer Indirect | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,038	[4]	1,990	[4]
Consumer Indirect | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	660	[3],[4]	778	[3],[4]
Consumer Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	632	[4]	540	[4]
Consumer Credit Card | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	435	[4]	347	[4]
Consumer Credit Card | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	152	[4]	142	[4]
Consumer Credit Card | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 45	[3],[4]	$ 51	[3],[4]

[1] 2 Includes loans of consolidated VIEs365 3,322

[2] Excludes $4.3 billion and $6.7 billion at December 31, 2012 and 2011, respectively, of guaranteed residential loans. At both December 31, 2012 and 2011, the majority of these loans had FICO scores of 700 and above.

[3] For substantially all loans with refreshed FICO scores below 620, the borrower’s FICO score at the time of origination exceeded 620 but has since deteriorated as the loan has seasoned.

[4] Excludes $5.4 billion and $7.2 billion at December 31, 2012 and 2011, respectively, of guaranteed student loans.