Loans - Status of Consumer Loan Portfolio (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual Loans	$ 1,072		$ 1,305
Accruing Loans Contractually Past Due 90 days or More	25		34
Total loans	73,439		67,695		67,710
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	18,437		18,147
Nonaccrual Loans	919		1,026
Accruing Loans Contractually Past Due 90 days or More	21		28
Total loans	19,377		19,201
Consumer Loans [Member] | Total residential mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	17,307		16,811
Nonaccrual Loans	919	[1],[2],[3]	1,026	[1],[2],[3]
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	18,226		17,837
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	15,551		14,877
Nonaccrual Loans	851		949
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	16,402		15,826		15,720
Consumer Loans [Member] | Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	1,756		1,934
Nonaccrual Loans	68		77
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	1,824		2,011		2,087
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	676		840
Nonaccrual Loans	0		0
Accruing Loans Contractually Past Due 90 days or More	10		14
Total loans	686		854		856
Consumer Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	454		496
Nonaccrual Loans	0		0
Accruing Loans Contractually Past Due 90 days or More	11		14
Total loans	$ 465		$ 510		$ 538

[1] Residential mortgage nonaccrual 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 customer loan portfolio.

[2] Nonaccrual residential mortgages includes 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.

[3] At September 30, 2014 and December 31, 2013, residential mortgage loan nonaccrual balances include $827 million and $841 million, respectively, of loans that are carried at the lower of amortized cost or fair value of the collateral less cost to sell.