Business Segments - Reconciliation of IFRS Basis Segment Results (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Segment Reporting [Line Items]
US GAAP based Net interest income	$ 210		$ 229		$ 667		$ 861
US GAAP based Other operating income (Total other revenues)	169		114		298		1,096
US GAAP based Total operating income (loss)	379		343		965		1,957
US GAAP based Loan impairment charges (Provision for credit losses)	(43)		(160)		(238)		131
US GAAP Net interest income and other operating income less provision for credit losses	422		503		1,203		1,826
US GAAP based Operating expenses	174		216		512		679
Income from continuing operations before income tax	248		287		691		1,147
US GAAP based Customer loans (Receivables)	23,503		27,844		23,503		27,844
US GAAP based Assets	32,579		40,779		32,579		40,779
IFRS Basis Consolidated Totals [Member]
Segment Reporting [Line Items]
Net Interest Income	336		491		1,078		1,620
IFRS based Other operating income (Total other revenues)	104		(28)		(57)		(343)
IFRS based Total operating income (loss)	440		463		1,021		1,277
IFRS based Loan impairment charges (Provision for credit losses)	(76)		115		53		558
IFRS based Net interest income and other operating income less provision for credit losses	516		348		968		719
Provision For Credit Losses	189		207		529		615
IFRS based Profit (loss) before tax	327		141		439		104
IFRS based Customer loans (Receivables)	24,485		32,436		24,485		32,436
Total Assets	33,632		42,774		33,632		42,774
IFRS Adjustments [Member]
Segment Reporting [Line Items]
Net Interest Income	(63)	[1]	(187)	[1]	(218)	[1]	(514)	[1]
IFRS based Other operating income (Total other revenues)	7	[1]	63	[1]	179	[1]	1,183	[1]
IFRS based Total operating income (loss)	(56)	[1]	(124)	[1]	(39)	[1]	669	[1]
IFRS based Loan impairment charges (Provision for credit losses)	34	[1]	(275)	[1]	(291)	[1]	(427)	[1]
IFRS based Net interest income and other operating income less provision for credit losses	(90)	[1]	151	[1]	252	[1]	1,096	[1]
Provision For Credit Losses	(11)	[1]	5	[1]	0	[1]	53	[1]
IFRS based Profit (loss) before tax	(79)	[1]	146	[1]	252	[1]	1,043	[1]
IFRS based Customer loans (Receivables)	(949)	[1]	(4,553)	[1]	(949)	[1]	(4,553)	[1]
Total Assets	(1,053)	[1]	(1,995)	[1]	(1,053)	[1]	(1,995)	[1]
IFRS Reclassifications [Member]
Segment Reporting [Line Items]
Net Interest Income	(63)	[2]	(75)	[2]	(193)	[2]	(245)	[2]
IFRS based Other operating income (Total other revenues)	58	[2]	79	[2]	176	[2]	256	[2]
IFRS based Total operating income (loss)	(5)	[2]	4	[2]	(17)	[2]	11	[2]
IFRS based Loan impairment charges (Provision for credit losses)	(1)	[2]	0	[2]	0	[2]	0	[2]
IFRS based Net interest income and other operating income less provision for credit losses	(4)	[2]	4	[2]	(17)	[2]	11	[2]
Provision For Credit Losses	(4)	[2]	4	[2]	(17)	[2]	11	[2]
IFRS based Profit (loss) before tax	0	[2]	0	[2]	0	[2]	0	[2]
IFRS based Customer loans (Receivables)	(33)	[2]	(39)	[2]	(33)	[2]	(39)	[2]
Total Assets	$ 0	[2]	$ 0	[2]	$ 0	[2]	$ 0	[2]

[1] IFRSs Adjustments consist of the accounting differences between U.S. GAAP and IFRSs which have been described in Note 18, "Business Segments," in the 2013 Form 10-K.

[2] Represents differences in balance sheet and income statement presentation between U.S. GAAP and IFRSs.