Receivables - Receivables Classified as Troubled Debt Restructuring Loan (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 49	$ 115	$ 115	$ 290
Receivables Held For Sale [Member] | Real Estate Secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	37	7	39	23
First lien [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	7	94	62	236
Second lien [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 5	$ 14	$ 14	$ 31