Receivables, net - Receivables Classified as Troubled Debt Restructuring Loan (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 28	$ 66
Receivables Held For Sale [Member] | Real Estate Secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	20	2
First lien [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	4	55
Second lien [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 4	$ 9