Loans - Status of Consumer Loan Portfolio (Detail) - USD ($) $ in Millions		Sep. 30, 2016		Dec. 31, 2015	Sep. 30, 2015
Financing Receivable, Recorded Investment [Line Items]
Accruing Loans Contractually Past Due 90 days or More		$ 17		$ 17
Total loans		77,625		82,917	$ 84,942
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		19,115		19,563
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest		462		885
Accruing Loans Contractually Past Due 90 days or More		16		16
Total loans		19,593		20,464
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		16,702	[1]	16,944
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	[2],[3],[4],[5]	389		814
Accruing Loans Contractually Past Due 90 days or More		0	[1]	0
Total loans		17,091	[1],[6]	17,758	17,460
Consumer Loans [Member] | Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		1,381		1,529
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	[2],[4]	73		71
Accruing Loans Contractually Past Due 90 days or More		0		0
Total loans		1,454		1,600	1,639
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		659		690
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest		0		0
Accruing Loans Contractually Past Due 90 days or More		9		9
Total loans		668		699	682
Consumer Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Performing Loans		373		400
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest		0		0
Accruing Loans Contractually Past Due 90 days or More		7		7
Total loans		$ 380		$ 407	$ 409

[1] The decrease in nonaccrual loans at September 30, 2016 reflects the impact of transfers of certain residential mortgage loans to held for sale during the nine months ended September 30, 2016.

[2] At September 30, 2016 and December 31, 2015, nonaccrual consumer mortgage loans held for investment include $318 million and $768 million, respectively, of loans that are carried at the lower of amortized cost or fair value of the collateral less cost to sell.

[3] Nonaccrual consumer mortgage loans for all periods does not include guaranteed loans purchased from the Government National Mortgage Association. 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.

[4] Nonaccrual consumer mortgage loans held for investment include all loans 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.

[5] The trend in nonaccrual loans reflects the impact of transfers of certain residential mortgage loans to held for sale during the nine months ended September 30, 2016.

[6] The decrease in past due loans at September 30, 2016 reflects the impact of transfers of certain residential mortgage loans to held for sale during the nine months ended September 30, 2016. See Note 6, "Loans Held for Sale" for additional details.