Business Segments - Reconciliation of IFRS Basis Segment Results (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Operating Statistics [Line Items]
US GAAP based Net interest income	$ 394		$ 408
US GAAP based Other operating income (Total other revenues)	354		(195)
US GAAP based Total operating income (loss)	748		213
US GAAP based Loan impairment charges (Provision for credit losses)	(24)		(791)
US GAAP Net interest income and other operating income less provision for credit losses	724		(578)
US GAAP based Operating expenses	268		215
Income (loss) from continuing operations before income tax	456		(793)
US GAAP based Customer loans (Receivables)	31,930		46,041
US GAAP based Assets	44,733		50,794
IFRS Basis Consolidated Totals
Operating Statistics [Line Items]
IFRS based Net Interest Income	636		645
IFRS based Other operating income (Total other revenues)	(199)		(318)
IFRS based Total operating income (loss)	437		327
IFRS based Loan impairment charges (Provision for credit losses)	(319)		(854)
IFRS based Net interest income and other operating income less provision for credit losses	118		(527)
IFRS based Operating expense	(255)		(189)
IFRS based Profit (loss) before tax	(137)		(716)
IFRS based Customer loans (Receivables)	36,021		46,199
IFRS based Assets	46,941		53,576
IFRS Adjustments
Operating Statistics [Line Items]
IFRS based Net Interest Income	(159)	[1]	(121)	[1]
IFRS based Other operating income (Total other revenues)	462	[1]	(14)	[1]
IFRS based Total operating income (loss)	303	[1]	(135)	[1]
IFRS based Loan impairment charges (Provision for credit losses)	295	[1]	63	[1]
IFRS based Net interest income and other operating income less provision for credit losses	598	[1]	(72)	[1]
IFRS based Operating expense	(5)	[1]	(5)	[1]
IFRS based Profit (loss) before tax	593	[1]	(77)	[1]
IFRS based Customer loans (Receivables)	(4,050)	[1]	(104)	[1]
IFRS based Assets	(2,208)	[1]	(2,782)	[1]
IFRS Reclassifications
Operating Statistics [Line Items]
IFRS based Net Interest Income	(83)	[2]	(116)	[2]
IFRS based Other operating income (Total other revenues)	91	[2]	137	[2]
IFRS based Total operating income (loss)	8	[2]	21	[2]
IFRS based Loan impairment charges (Provision for credit losses)	0	[2]	0	[2]
IFRS based Net interest income and other operating income less provision for credit losses	8	[2]	21	[2]
IFRS based Operating expense	(8)	[2]	(21)	[2]
IFRS based Profit (loss) before tax	0	[2]	0	[2]
IFRS based Customer loans (Receivables)	(41)	[2]	(54)	[2]
IFRS based Assets	$ 0	[2]	$ 0	[2]

[1] IFRS Adjustments consist of the accounting differences between U.S. GAAP and IFRSs which have been described more fully above.

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