Loans - Delinquency Ratio for Consumer Loan (Detail) (Consumer Loans [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	$ 1,044		$ 1,103
Delinquency Ratio	5.24%		5.59%
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	957	[1],[2]	1,013	[1],[2]
Delinquency Ratio	5.62%	[1],[2]	6.07%	[1],[2]
Home Equity Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	60	[1],[2]	62	[1],[2]
Delinquency Ratio	3.50%	[1],[2]	3.48%	[1],[2]
Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	14		14
Delinquency Ratio	2.06%		1.94%
Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Delinquent Loans	$ 13		$ 14
Delinquency Ratio	2.53%		2.52%

[1] At March 31, 2015 and December 31, 2014, consumer mortgage loans include $609 million and $608 million, respectively, of loans that were in the process of foreclosure.

[2] At March 31, 2015 and December 31, 2014, consumer mortgage loan delinquency includes $908 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.