LHFI by Credit Quality Indicator (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 129,744	[1]	$ 127,877	[1]
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	61,337		57,974
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	6,105		5,481
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,096		855
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	24,173	[2],[3]	24,412	[2],[4]
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	14,519	[2]	14,809	[2]
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	508	[2]	553	[2]
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,675	[5]	2,829	[5]
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,501	[5]	11,272	[5]
Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	749	[5]	731	[5]
Pass | Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	59,854		56,443
Pass | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	5,902		5,245
Pass | Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,059		798
Criticized Accruing | Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,284		1,335
Criticized Accruing | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	165		197
Criticized Accruing | Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	27		45
Criticized Nonaccruing | Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	199		196
Criticized Nonaccruing | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	38		39
Criticized Nonaccruing | Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10		12
FICO Score 700 and Above [Member] | Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	19,038	[2]	19,100	[2]
FICO Score 700 and Above [Member] | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,558	[2]	11,661	[2]
FICO Score 700 and Above [Member] | Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	385	[2]	423	[2]
FICO Score 700 and Above [Member] | Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,161	[5]	2,370	[5]
FICO Score 700 and Above [Member] | Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,554	[5]	8,420	[5]
FICO Score 700 and Above [Member] | Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	528	[5]	512	[5]
FICO Score Between 620 and 699 | Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,603	[2]	3,652	[2]
FICO Score Between 620 and 699 | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,087	[2]	2,186	[2]
FICO Score Between 620 and 699 | Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	89	[2]	90	[2]
FICO Score Between 620 and 699 | Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	453	[5]	397	[5]
FICO Score Between 620 and 699 | Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,316	[5]	2,228	[5]
FICO Score Between 620 and 699 | Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	178	[5]	176	[5]
FICO Score Below 620 | Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,532	[2],[6]	1,660	[2],[6]
FICO Score Below 620 | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	874	[2],[6]	962	[2],[6]
FICO Score Below 620 | Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	34	[2],[6]	40	[2],[6]
FICO Score Below 620 | Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	61	[5],[6]	62	[5],[6]
FICO Score Below 620 | Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	631	[5],[6]	624	[5],[6]
FICO Score Below 620 | Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 43	[5],[6]	$ 43	[5],[6]

[1] Includes loans of consolidated VIEs of $307 million and $327 million at June 30, 2014 and December 31, 2013, respectively.

[2] Excludes $661 million and $3.4 billion at June 30, 2014 and December 31, 2013, respectively, of guaranteed residential loans. At June 30, 2014 and December 31, 2013, the majority of these loans had FICO scores of 700 and above.

[3] Includes $292 million of loans carried at fair value, the majority of which were accruing current.

[4] Includes $302 million of loans carried at fair value, the majority of which were accruing current.

[5] Excludes $5.4 billion and $5.5 billion of guaranteed student loans at June 30, 2014 and December 31, 2013, respectively.

[6] 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.