Loans - Delinquency Ratio for Consumer Loan (Detail) - Consumer Loans [Member] - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans		$ 948	$ 1,103
Delinquency Ratio		4.67%	5.59%
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	[1],[2]	$ 868	$ 1,013
Delinquency Ratio	[1],[2]	4.97%	6.07%
Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	[1],[2]	$ 54	$ 62
Delinquency Ratio	[1],[2]	3.29%	3.48%
Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans		$ 13	$ 14
Delinquency Ratio		1.91%	1.94%
Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans		$ 13	$ 14
Delinquency Ratio		2.64%	2.52%

[1] At September 30, 2015 and December 31, 2014, consumer mortgage loan delinquency includes $794 million and $936 million, respectively, of loans that are carried at the lower of amortized cost or fair value of the collateral less cost to sell.

[2] At September 30, 2015 and December 31, 2014, consumer mortgage loans include $598 million and $658 million, respectively, of loans that were in the process of foreclosure.