Loans - Status of Consumer Loan Portfolio (Detail) (USD $)	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual Loans	$ 1,360,000,000		$ 1,629,000,000
Accruing Loans Contractually Past Due 90 days or More	46,000,000		80,000,000
Total loans	67,710,000,000		63,258,000,000		61,452,000,000
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	18,059,000,000		17,936,000,000
Nonaccrual Loans	1,105,000,000		1,129,000,000
Accruing Loans Contractually Past Due 90 days or More	37,000,000		43,000,000
Total loans	19,201,000,000		19,108,000,000
Consumer Loans [Member] | Total residential mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	16,702,000,000		16,571,000,000
Nonaccrual Loans	1,105,000,000	[1]	1,124,000,000	[1]
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	17,807,000,000		17,695,000,000
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	14,700,000,000		14,333,000,000
Nonaccrual Loans	1,020,000,000		1,038,000,000
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	15,720,000,000		15,371,000,000		15,086,000,000
Consumer Loans [Member] | Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	2,002,000,000		2,238,000,000
Nonaccrual Loans	85,000,000		86,000,000
Accruing Loans Contractually Past Due 90 days or More	0		0
Total loans	2,087,000,000		2,324,000,000		2,387,000,000
Consumer Loans [Member] | Credit Card Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	843,000,000		800,000,000
Nonaccrual Loans	0		0
Accruing Loans Contractually Past Due 90 days or More	13,000,000		15,000,000
Total loans	856,000,000		815,000,000		796,000,000
Consumer Loans [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans	514,000,000		565,000,000
Nonaccrual Loans	0		5,000,000
Accruing Loans Contractually Past Due 90 days or More	24,000,000		28,000,000
Total loans	$ 538,000,000		$ 598,000,000		$ 615,000,000

[1] 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.