Composition of the Company's Loan Portfolio (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 132,380	[1]	$ 133,112	[1]
Loans Held for Sale	3,404	[2]	3,232	[2]
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	73,447		73,392
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	38,445		38,775
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	20,488		20,945
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	65,574		65,440
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	6,389		6,741
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,484		1,211
Residential Guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	655		632
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	23,419	[3],[4]	23,443	[3],[4]
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	13,954	[3]	14,264	[3]
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	417	[3]	436	[3]
Federally Guaranteed Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,337		4,827
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,937	[5]	4,573	[5]
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,336	[5]	10,644	[5]
Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 878	[5]	$ 901	[5]

[1] Includes loans of consolidated VIEs of $277 million and $288 million at March 31, 2015 and December 31, 2014, respectively.

[2] Includes $2.1 billion and $1.9 billion of LHFS carried at fair value at March 31, 2015 and December 31, 2014, respectively.

[3] Excludes $655 million and $632 million of guaranteed residential loans at March 31, 2015 and December 31, 2014, respectively.

[4] Includes $268 million of loans carried at fair value, the majority of which were accruing current.

[5] Excludes $4.3 billion and $4.8 billion of guaranteed student loans at March 31, 2015 and December 31, 2014, respectively.