Loans - Status of Consumer Loan Portfolio (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Financing Receivable, Recorded Investment [Line Items]
Accruing Loans Contractually Past Due 90 days or More		$ 19	$ 21
Total loans		83,617	77,741	$ 72,198
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		19,135	18,719
Nonaccrual loans		868	915
Accruing Loans Contractually Past Due 90 days or More		18	20
Total loans		20,021	19,654
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		16,435	15,814
Nonaccrual loans	[1],[2],[3]	798	847
Accruing Loans Contractually Past Due 90 days or More		0	0
Total loans		17,233	16,661	16,097
Consumer Loans [Member] | Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		1,616	1,716
Nonaccrual loans	[1],[3]	70	68
Accruing Loans Contractually Past Due 90 days or More		0	0
Total loans		1,686	1,784	1,914
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		683	710
Nonaccrual loans		0	0
Accruing Loans Contractually Past Due 90 days or More		9	10
Total loans		692	720	681
Consumer Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		401	479
Nonaccrual loans		0	0
Accruing Loans Contractually Past Due 90 days or More		9	10
Total loans		$ 410	$ 489	$ 473

[1] At June 30, 2015 and December 31, 2014, nonaccrual consumer mortgage loans include $755 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.