LHFI by Credit Quality Indicator (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 122,031	[1]	$ 121,470	[1]
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	55,070		54,048
Commercial and Industrial | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	53,339		52,292
Commercial and Industrial | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,504		1,562
Commercial and Industrial | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	227		194
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,308		4,127
Commercial Real Estate | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,876		3,564
Commercial Real Estate | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	378		497
Commercial Real Estate | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	54		66
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	667		713
Commercial Construction [Member] | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	534		506
Commercial Construction [Member] | Criticized Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	110		173
Commercial Construction [Member] | Criticized Nonaccruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23		34
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23,341	[2]	23,389	[2]
Residential Nonguaranteed [Member] | FICO Score 700 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	17,671	[2]	17,410	[2]
Residential Nonguaranteed [Member] | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,730	[2]	3,850	[2]
Residential Nonguaranteed [Member] | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,940	[2],[3]	2,129	[2],[3]
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	14,682	[2]	14,805	[2]
Home Equity | FICO Score 700 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,376	[2]	11,339	[2]
Home Equity | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,244	[2]	2,297	[2]
Home Equity | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,062	[2],[3]	1,169	[2],[3]
Residential Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	635	[2]	753	[2]
Residential Construction | FICO Score 700 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	482	[2]	561	[2]
Residential Construction | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	107	[2]	123	[2]
Residential Construction | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	46	[2],[3]	69	[2],[3]
Consumer Other Direct
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,483	[4]	2,396	[4]
Consumer Other Direct | FICO Score 700 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,051	[4]	1,980	[4]
Consumer Other Direct | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	367	[4]	350	[4]
Consumer Other Direct | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	65	[3],[4]	66	[3],[4]
Consumer Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,151	[4]	10,998	[4]
Consumer Indirect | FICO Score 700 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,391	[4]	8,300	[4]
Consumer Indirect | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,141	[4]	2,038	[4]
Consumer Indirect | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	619	[3],[4]	660	[3],[4]
Consumer Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	641	[4]	632	[4]
Consumer Credit Card | FICO Score 700 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	442	[4]	435	[4]
Consumer Credit Card | FICO Score Between 620 and 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	155	[4]	152	[4]
Consumer Credit Card | FICO Score Below 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 44	[3],[4]	$ 45	[3],[4]

[1] 2 Includes loans of consolidated VIEs345 365

[2] Excludes $3.6 billion and $4.3 billion at June 30, 2013 and December 31, 2012, respectively, of guaranteed residential loans. At June 30, 2013 and December 31, 2012, 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 of guaranteed student loans at June 30, 2013 and December 31, 2012