Receivables - Summary of Contractual Delinquency and Delinquency Ratio (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	$ 6,273	$ 8,591
Delinquency Ratio	16.03%	17.93%
First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	5,821	7,605
Delinquency Ratio	18.01%	19.89%
Second Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	349	500
Delinquency Ratio	9.59%	11.16%
Real estate secured [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	6,170	8,105
Delinquency Ratio	17.16%	18.98%
Personal non-credit card [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	$ 103	$ 486
Delinquency Ratio	3.24%	9.35%