Receivables Held for Investment, net - Receivables Classified as Troubled Debt Restructuring Loan (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 19	$ 44	$ 72	$ 159
Receivables Held For Sale [Member] | Real estate secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	19	32	57	71
First lien held for investment [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	0	6	7	68
Second lien held for investment [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 0	$ 6	$ 8	$ 20