Loans - Status of Consumer Loan Portfolio (Detail) - USD ($) $ in Millions		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Accruing Loans Contractually Past Due 90 days or More		$ 17		$ 21
Total loans		82,917		77,741	$ 67,695
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		19,563		18,719
Nonaccrual Loans		885		915
Accruing Loans Contractually Past Due 90 days or More		16		20
Total loans		20,464		19,654
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		16,944		15,814
Nonaccrual Loans	[1],[2],[3]	814		847
Accruing Loans Contractually Past Due 90 days or More		0		0
Total loans		17,758		16,661	15,826
Consumer Loans [Member] | Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		1,529		1,716
Nonaccrual Loans	[1],[3]	71		68
Accruing Loans Contractually Past Due 90 days or More		0		0
Total loans		1,600	[4]	1,784	2,011
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		690		710
Nonaccrual Loans		0		0
Accruing Loans Contractually Past Due 90 days or More		9		10
Total loans		699	[5]	720	854
Consumer Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		400		479
Nonaccrual Loans	[1],[3]	0		0
Accruing Loans Contractually Past Due 90 days or More		7		10
Total loans		$ 407		$ 489	$ 510

[1] At December 31, 2015 and 2014, nonaccrual consumer mortgage loans include $768 million and $817 million, respectively, of loans that are carried at the lower of amortized cost or fair value of the collateral less cost to sell.

[2] Nonaccrual consumer mortgage loans for all periods does not include guaranteed loans purchased from the Government National Mortgage Association ("GNMA"). Repayment of these loans are predominantly insured by the Federal Housing Administration and as such, these loans have different risk characteristics from the rest of our consumer loan portfolio.

[3] Nonaccrual consumer mortgage loans include all receivables which are 90 or more days contractually delinquent as well as loans discharged under Chapter 7 bankruptcy and not re-affirmed and second lien loans where the first lien loan that we own or service is 90 or more days contractually delinquent.

[4] Home equity mortgage maturities reflect estimates based on historical payment patterns.

[5] As credit card receivables do not have stated maturities, the table reflects estimates based on historical payment patterns.