Receivables - Summary of Contractual Delinquency and Delinquency Ratio (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
First Lien [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	$ 1,426	$ 2,387
Delinquency Ratio	6.84%	10.13%
Second Lien [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	164	275
Delinquency Ratio	6.15%	9.12%
Real estate secured [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	2,791	4,135
Delinquency Ratio	11.01%	14.44%
Receivables Held For Sale [Member] | Real Estate Secured [Member]
Financing Receivable, Modifications [Line Items]
Dollars of Delinquency	$ 1,201	$ 1,473
Delinquency Ratio	65.27%	71.96%