Composition of the Company's Loan Portfolio (Detail) - USD ($) $ in Millions		Dec. 31, 2016		Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[1]	$ 143,298		$ 136,442
Loans Held for Sale	[2]	4,169		1,838
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		69,213		67,062
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		4,996		6,236
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		4,015		1,954
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		78,224		75,252
Federal National Mortgage Association (FNMA) Insured Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		537		629
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	26,137	[4]	24,744	[5]
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	11,912		13,171
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[3]	404		384
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		38,990		38,928
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		6,167		4,922
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[6]	7,771		6,127
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[6]	10,736		10,127
Credit Card Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	[6]	1,410		1,086
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment		$ 26,084		$ 22,262

[1] Includes loans of consolidated VIEs of $211 million and $246 million at December 31, 2016 and December 31, 2015, respectively.

[2] Includes $3.5 billion and $1.5 billion of LHFS measured at fair value at December 31, 2016 and 2015, respectively.

[3] Excludes $537 million and $629 million of guaranteed residential loans at December 31, 2016 and 2015, respectively.

[4] Includes $222 million of loans measured at fair value, the majority of which were accruing current.

[5] Includes $257 million of loans measured at fair value, the majority of which were accruing current.

[6] Excludes $6.2 billion and $4.9 billion of guaranteed student loans at December 31, 2016 and 2015, respectively.