Business Segments - Reconciliation of Group Reporting Basis Segment Results (Detail) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Segment Reporting [Line Items]
US GAAP based Net interest income		$ 168		$ 225	$ 352		$ 457
US GAAP based Other operating income (Total other revenues)		138		47	96		129
US GAAP based Total operating income (loss)		306		272	448		586
US GAAP based Loan impairment charges (Provision for credit losses)		192	[1]	(197)	219	[1]	(195)
US GAAP Net interest income and other operating income less provision for credit losses		114		469	229		781
US GAAP based Operating expenses		522		121	670		338
Income (loss) from continuing operations before income tax		(408)		348	(441)		443
US GAAP based Customer loans (Receivables)		10,307		24,473	10,307		24,473
US GAAP based Assets		27,502		34,338	27,502		34,338
Group Reporting Basis Consolidated Totals [Member]
Segment Reporting [Line Items]
Net Interest Income		250		370	531		742
Group Reporting Basis Other operating income (Total other revenues)		127		(77)	49		(161)
Group Reporting Basis Total operating income (loss)		377		293	580		581
Group Reporting Basis Loan impairment charges (Provision for credit losses)		28		11	49		129
Group Reporting Basis Net interest income and other operating income less loan impairment charges		349		282	531		452
Operating expenses		526		124	674		340
Profit (loss) before tax		(177)		158	(143)		112
Group Reporting Basis Customer loans (Receivables)		21,792		26,379	21,792		26,379
Total Assets		28,960		35,784	28,960		35,784
Group Reporting Basis Adjustments [Member]
Segment Reporting [Line Items]
Net Interest Income	[2]	(29)		(80)	(69)		(155)
Group Reporting Basis Other operating income (Total other revenues)	[2]	(39)		67	(60)		172
Group Reporting Basis Total operating income (loss)	[2]	(68)		(13)	(129)		17
Group Reporting Basis Loan impairment charges (Provision for credit losses)	[2]	164		(209)	170		(325)
Group Reporting Basis Net interest income and other operating income less loan impairment charges	[2]	(232)		196	(299)		342
Operating expenses	[2]	(1)		6	(1)		11
Profit (loss) before tax	[2]	(231)		190	(298)		331
Group Reporting Basis Customer loans (Receivables)	[2]	(11,459)		(1,871)	(11,459)		(1,871)
Total Assets	[2]	(1,458)		(1,446)	(1,458)		(1,446)
Group Reporting Basis Reclassifications [Member]
Segment Reporting [Line Items]
Net Interest Income	[3]	(53)		(65)	(110)		(130)
Group Reporting Basis Other operating income (Total other revenues)	[3]	50		57	107		118
Group Reporting Basis Total operating income (loss)	[3]	(3)		(8)	(3)		(12)
Group Reporting Basis Loan impairment charges (Provision for credit losses)	[3]	0		1	0		1
Group Reporting Basis Net interest income and other operating income less loan impairment charges	[3]	(3)		(9)	(3)		(13)
Operating expenses	[3]	(3)		(9)	(3)		(13)
Profit (loss) before tax	[3]	0		0	0		0
Group Reporting Basis Customer loans (Receivables)	[3]	(26)		(35)	(26)		(35)
Total Assets	[3]	$ 0		$ 0	$ 0		$ 0

[1] The provision for credit losses and charge-offs for real estate secured receivables during the three and six months ended June 30, 2015 includes $220 million related to the lower of amortized cost or fair value adjustment attributable to credit factors for receivables transferred to held for sale in June 2015. See Note 5, "Receivables Held for Sale," for additional information. The provision for credit losses for real estate secured receivables during the six months ended June 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 the 2014 Form 10-K

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