Loans - Delinquency Ratio for Consumer Loan (Detail) - Consumer Loans [Member] - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans		$ 836	$ 938
Delinquency Ratio		4.05%	4.56%
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	[1],[2]	$ 765	$ 858
Delinquency Ratio	[1],[2]	4.23%	4.83%
Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	[1],[2]	$ 46	$ 56
Delinquency Ratio	[1],[2]	3.26%	3.50%
Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans		$ 14	$ 13
Delinquency Ratio		2.03%	1.86%
Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans		$ 11	$ 11
Delinquency Ratio		2.43%	2.26%

[1] At December 31, 2016 and 2015, consumer mortgage loan delinquency includes $711 million and $793 million, respectively, of loans that are carried at the lower of amortized cost or fair value of the collateral less cost to sell, including $358 million and $3 million, respectively, relating to loans held for sale.

[2] At December 31, 2016 and 2015, consumer mortgage loans and loans held for sale include $474 million and $567 million, respectively, of loans that were in the process of foreclosure.