Receivables, net - TDR Loans (Detail) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Unpaid principal balance subject to reduction		$ 757	$ 740
TDR Loans held for investment, recorded at the lower of amortized cost or FV less cost to sell		211	250
First lien [Member]
Financing Receivable, Modifications [Line Items]
Carrying value of TDR Loans	[1],[2]	722	870
Unpaid balance of TDR loans	[1],[2]	834	1,003
Credit loss reserves for TDR loans	[3]	72	95
Second lien [Member]
Financing Receivable, Modifications [Line Items]
Carrying value of TDR Loans	[1],[2]	641	652
Unpaid balance of TDR loans	[1],[2]	712	732
Credit loss reserves for TDR loans	[3]	133	135
Receivables Held For Sale [Member] | Real Estate Secured [Member]
Financing Receivable, Modifications [Line Items]
Carrying value of TDR Loans	[2],[4]	6,105	6,044
Unpaid balance of TDR loans	[2],[4]	7,381	7,317
Real estate secured [Member]
Financing Receivable, Modifications [Line Items]
Carrying value of TDR Loans	[2]	7,468	7,566
Unpaid balance of TDR loans	[2]	8,927	9,052
Credit loss reserves for TDR loans	[3],[4]	$ 205	$ 230

[1] At March 31, 2016 and December 31, 2015, the carrying value of TDR Loans held for investment totaling $211 million and $250 million, respectively, are recorded at the lower of amortized cost or fair value of the collateral less cost to sell.

[2] At March 31, 2016 and December 31, 2015, the unpaid principal balance reflected above includes $757 million and $740 million, respectively, which have received a reduction in the unpaid principal balance as part of an account management action.

[3] Included in credit loss reserves.

[4] There are no credit loss reserves associated with receivables classified as held for sale as they are carried at the lower of amortized cost or fair value.