Composition of the Company's Loan Portfolio (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[1]	$ 132,538	$ 133,112
Loans Held for Sale	[2]	2,457	3,232
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		73,301	73,392
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		38,736	38,775
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		20,501	20,945
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		65,713	65,440
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		6,058	6,741
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		1,530	1,211
Residential Guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		625	632
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3],[4]	24,038	23,443
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	13,672	14,264
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	401	436
Federally Guaranteed Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		4,401	4,827
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[5]	5,329	4,573
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[5]	9,834	10,644
Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[5]	$ 937	$ 901

[1] Includes loans of consolidated VIEs of $266 million and $288 million at June 30, 2015 and December 31, 2014, respectively.

[2] Includes $1.9 billion of LHFS carried at fair value at both June 30, 2015 and December 31, 2014.

[3] Excludes $625 million and $632 million of guaranteed residential loans at June 30, 2015 and December 31, 2014, respectively.

[4] Includes $263 million of loans carried at fair value, the majority of which were accruing current.

[5] Excludes $4.4 billion and $4.8 billion of guaranteed student loans at June 30, 2015 and December 31, 2014, respectively.