Composition of the Company's Loan Portfolio (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 132,151	[1]	$ 127,877	[1]
Loans Held for Sale	1,739	[2],[3]	1,699	[2]
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	71,094		64,310
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	39,222		43,190
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	21,835		20,377
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	63,140		57,974
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	6,704		5,481
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,250		855
Residential Guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	651		3,416
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23,718	[4],[5],[6]	24,412	[4],[5],[7]
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	14,389	[4]	14,809	[4]
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	464	[4]	553	[4]
Federally Guaranteed Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	5,314		5,545
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,110	[8]	2,829	[8]
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	11,594	[8]	11,272	[8]
Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	817	[8]	731	[8]
Loans Held For Investment [Member] | Federally Guaranteed Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 5,314

[1] Includes loans of consolidated VIEs of $298 million and $327 million at September 30, 2014 and December 31, 2013, respectively.

[2] Includes $1.6 billion and $1.4 billion of LHFS carried at fair value at September 30, 2014 and December 31, 2013, respectively.

[3] Includes loans held for sale, at fair value, of consolidated VIEs of $0 million and $261 million at September 30, 2014 and December 31, 2013, respectively.

[4] Excludes $651 million and $3.4 billion at September 30, 2014 and December 31, 2013, respectively, of guaranteed residential loans. At September 30, 2014 and December 31, 2013, the majority of these loans had FICO scores of 700 and above.

[5] Includes $284 million and $302 million of loans carried at fair value at September 30, 2014 and December 31, 2013, respectively.

[6] Includes $284 million of loans carried at fair value, the majority of which were accruing current.

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

[8] Excludes $5.3 billion and $5.5 billion of guaranteed student loans at September 30, 2014 and December 31, 2013, respectively.