Loans - Status of Consumer Loan Portfolio (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Accruing Loans Contractually Past Due 90 days or More	$ 21		$ 34
Total loans	77,741		67,695		63,258
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	18,719		18,147
Nonaccrual loans	915		1,026
Accruing Loans Contractually Past Due 90 days or More	20		28
Total loans	19,654		19,201
Consumer Loans [Member] | Total residential mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	17,530		16,811
Nonaccrual loans	915	[1],[2],[3]	1,026	[1],[2],[3]
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	18,445		17,837
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	15,814		14,877
Nonaccrual loans	847		949
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	16,661		15,826		15,371
Consumer Loans [Member] | Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	1,716		1,934
Nonaccrual loans	68		77
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	1,784	[4]	2,011		2,324
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	710		840
Nonaccrual loans	0		0
Accruing Loans Contractually Past Due 90 days or More	10		14
Total loans	720	[5]	854		815
Consumer Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	479		496
Nonaccrual loans	0		0
Accruing Loans Contractually Past Due 90 days or More	10		14
Total loans	$ 489		$ 510		$ 598

[1] At December 31, 2014 and 2013, residential mortgage loan nonaccrual balances include $817 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.

[2] 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.

[3] 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.

[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.