Composition of the Company's Loan Portfolio (Detail) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[1]	$ 141,656	$ 136,442
Loans Held for Sale	[2]	2,468	1,838
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		68,603	67,062
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		6,228	6,236
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		2,617	1,954
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		77,448	75,252
Federal National Mortgage Association (FNMA) Insured Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		534	629
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3],[4]	26,037	24,744
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	12,481	13,171
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	397	384
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		39,449	38,928
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		5,562	4,922
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[5]	6,825	6,127
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[5]	11,195	10,127
Credit Card Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[5]	1,177	1,086
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		$ 24,759	$ 22,262

[1] Includes loans of consolidated VIEs of $227 million and $246 million at June 30, 2016 and December 31, 2015, respectively.

[2] Includes $2.2 billion and $1.5 billion of LHFS measured at fair value at June 30, 2016 and December 31, 2015, respectively.

[3] Excludes $534 million and $629 million of guaranteed residential loans at June 30, 2016 and December 31, 2015, respectively.

[4] Includes $246 million of loans measured at fair value, the majority of which were accruing current.

[5] Excludes $5.6 billion and $4.9 billion of guaranteed student loans at June 30, 2016 and December 31, 2015, respectively.