Business Segments - Reconciliation of Group Reporting Basis Segment Results (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting [Line Items]
US GAAP based Net interest income		$ 109	$ 182	$ 431	$ 534
US GAAP based Other operating income (Total other revenues)		(11)	(98)	248	(2)
US GAAP based Total operating income (loss)		98	84	679	532
US GAAP based Loan impairment charges (Provision for credit losses)	[1]	572	18	621	237
US GAAP Net interest income and other operating income less provision for credit losses		(474)	66	58	295
US GAAP based Operating expenses		135	232	986	902
Loss from continuing operations before income tax		(609)	(166)	(928)	(607)
US GAAP based Customer loans (Receivables)		0	9,629	0	9,629
US GAAP based Assets		15,342	25,615	15,342	25,615
Group Reporting Basis Adjustments [Member]
Segment Reporting [Line Items]
Net Interest Income	[2]	(24)	(31)	(66)	(100)
Group Reporting Basis Other operating income (Total other revenues)	[2]	95	(80)	345	(140)
Group Reporting Basis Total operating income (loss)	[2]	71	(111)	279	(240)
Group Reporting Basis Loan impairment charges (Provision for credit losses)	[2]	558	31	508	201
Group Reporting Basis Net interest income and other operating income less loan impairment charges	[2]	(487)	(142)	(229)	(441)
Operating expenses	[2]	(7)	4	(1)	3
Profit (loss) before tax	[2]	(480)	(146)	(228)	(444)
Group Reporting Basis Customer loans (Receivables)	[2]	(10,531)	(9,477)	(10,531)	(9,477)
Total Assets	[2]	(1,064)	(1,603)	(1,064)	(1,603)
Group Reporting Basis Reclassifications [Member]
Segment Reporting [Line Items]
Net Interest Income	[3]	(6)	(39)	(26)	(149)
Group Reporting Basis Other operating income (Total other revenues)	[3]	7	42	27	149
Group Reporting Basis Total operating income (loss)	[3]	1	3	1	0
Group Reporting Basis Loan impairment charges (Provision for credit losses)	[3]	0	0	0	0
Group Reporting Basis Net interest income and other operating income less loan impairment charges	[3]	1	3	1	0
Operating expenses	[3]	1	3	1	0
Profit (loss) before tax	[3]	0	0	0	0
Group Reporting Basis Customer loans (Receivables)	[3]	0	(25)	0	(25)
Total Assets	[3]	0	0	0	0
Group Reporting Basis Consolidated Totals [Member]
Segment Reporting [Line Items]
Net Interest Income		139	252	523	783
Group Reporting Basis Other operating income (Total other revenues)		(113)	(60)	(124)	(11)
Group Reporting Basis Total operating income (loss)		26	192	399	772
Group Reporting Basis Loan impairment charges (Provision for credit losses)		14	(13)	113	36
Group Reporting Basis Net interest income and other operating income less loan impairment charges		12	205	286	736
Operating expenses		141	225	986	899
Profit (loss) before tax		(129)	(20)	(700)	(163)
Group Reporting Basis Customer loans (Receivables)		10,531	19,131	10,531	19,131
Total Assets		$ 16,406	$ 27,218	$ 16,406	$ 27,218

[1] The provision for credit losses and charge-offs for real estate secured receivables during the three and nine months ended September 30, 2016 include $557 million and $576 million, respectively, related to the lower of amortized cost or fair value adjustment attributable to credit factors for receivables transferred to held for sale. For the three and nine months ended September 30, 2015, the provision for credit losses and charge-offs included $12 million and $232 million, respectively, related to the lower of amortized cost or fair value adjustment attributable to credit factors for receivables transferred to held for sale. See Note 4, "Receivables Held for Sale," for additional information. During the nine months ended September 30, 2016, net charge-offs dollars were impacted by an out of period adjustment which decreased net charge-offs by $12 million in order to properly reflect charge-offs for receivables which received a partial forgiveness of principal as a result of an account modification in prior periods. The provision for credit losses for real estate secured receivables during the nine months ended September 30, 2015 was impacted by a release of approximately $19 million associated with a correction to our credit loss reserve calculation for a segment of our portfolio.

[2] Group Reporting Basis Adjustments consist of accounting differences between U.S. GAAP and the Group Reporting Basis which have been described in Note 18, "Business Segments," in our 2015 Form 10-K.

[3] Represents differences in balance sheet and income statement presentation between U.S. GAAP and the Group Reporting Basis.