Receivables, net - Receivables Classified as Troubled Debt Restructuring Loan (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 186	$ 453	$ 1,244
Consumer Loan Excluding Credit Card Held-for-Sale [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	0	0	21
Receivables Held For Sale [Member] | Real Estate Secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	90	33	342
Receivables Held For Sale and Held for Investment [Member] | Real Estate Secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	186	453	1,223
First lien [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	72	367	765
Second lien [Member]
Receivables classified as Trouble Debt Restructuring Loans
TDR loans that became delinquent during the period	$ 24	$ 53	$ 116