LHFI by Credit Quality Indicator (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 121,817	[1]	$ 122,495	[1]
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	52,407		49,538
Commercial and Industrial | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	50,496		47,683
Commercial and Industrial | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,623		1,507
Commercial and Industrial | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	288		348
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,491		5,094
Commercial Real Estate | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,788		3,845
Commercial Real Estate | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	584		961
Commercial Real Estate | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	119		288
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	808		1,240
Commercial Construction [Member] | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	524		581
Commercial Construction [Member] | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	209		369
Commercial Construction [Member] | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	75		290
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23,925	[2]	23,243	[2]
Residential Nonguaranteed [Member] | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	17,550	[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	4,071	[2]	4,132	[2]
Residential Nonguaranteed [Member] | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,304	[2],[3]	2,972	[2],[3]
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	15,019	[2]	15,765	[2]
Home Equity | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,454	[2]	11,084	[2]
Home Equity | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,339	[2]	2,903	[2]
Home Equity | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,226	[2],[3]	1,778	[2],[3]
Residential Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	805	[2]	980	[2]
Residential Construction | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	594	[2]	661	[2]
Residential Construction | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	137	[2]	202	[2]
Residential Construction | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	74	[2],[3]	117	[2],[3]
Consumer Other Direct
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,341	[4]	2,059	[4]
Consumer Other Direct | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,930	[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	343	[4]	359	[4]
Consumer Other Direct | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	68	[3],[4]	86	[3],[4]
Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,781	[4]	10,165	[4]
Consumer Indirect | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,156	[4]	7,397	[4]
Consumer Indirect | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,992	[4]	1,990	[4]
Consumer Indirect | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	633	[3],[4]	778	[3],[4]
Consumer Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	594	[4]	540	[4]
Consumer Credit Card | FICO Score 700 and Above
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	404	[4]	347	[4]
Consumer Credit Card | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	145	[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 VIEs374 3,322

[2] Excludes $4.8 billion and $6.7 billion at September 30, 2012 and December 31, 2011, respectively, of guaranteed residential loans. At both September 30, 2012 and December 31, 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 $5.8 billion and $7.2 billion at September 30, 2012 and December 31, 2011, respectively, of guaranteed student loans.