Parent And Guarantor Consolidating Financial Statements (Schedule of Consolidating Statement of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									$ 4,603	$ 4,409	$ 4,475
Interest on loans held-for-sale									155	332	587
Interest on trading assets									13	19	15
Interest and dividends on available-for-sale investment securities									292	351	323
Interest-bearing cash									26	21	34
Operating leases									2,379	1,929	2,583
Total financing revenue and other interest income									7,468	7,061	8,017
Interest on deposits									644	614	579
Interest on short-term borrowings									90	116	141
Interest on long-term debt									3,466	4,309	4,740
Total interest expense									4,200	5,039	5,460
Depreciation expense on operating lease assets									1,399	941	1,251
Net financing revenue (loss)	611	473	443	342	286	247	341	207	1,869	1,081	1,306
Nonbank subsidiaries									0	0	0
Servicing fees									701	1,358	1,488
Servicing asset valuation and hedge activities, net									(8)	(789)	(394)
Total servicing income, net									693	569	1,094
Insurance premiums and service revenue earned									1,059	1,170	1,371
Gain (loss) on mortgage and automotive loans, net									532	470	1,239
Gain (loss) on extinguishment of debt									(148)	(64)	(124)
Other gain (loss) on investments, net									146	259	502
Other income, net of losses									747	493	334
Total other revenue	481	774	762	1,012	812	385	873	827	3,029	2,897	4,416
Total net revenue (loss)	1,092	1,247	1,205	1,354	1,098	632	1,214	1,034	4,898	3,978	5,722
Provision for loan losses	92	105	34	98	(13)	57	59	85	329	188	357
Compensation and benefits expense									1,365	1,322	1,348
Insurance losses and loss adjustment expenses									461	483	547
Other operating expenses									3,498	2,936	3,078
Total noninterest expense	1,037	877	2,290	1,120	1,420	983	1,277	1,061	5,324	4,741	4,973
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries	(37)	265	(1,119)	136	(309)	(408)	(122)	(112)	(755)	(951)	392
Income tax expense (benefit) from continuing operations	(1,337)	43	(8)	18	10	13	9	19	(1,284)	51	104
Net income (loss) from continuing operations	1,300	222	(1,111)	118	(319)	(421)	(131)	(131)	529	(1,002)	288
Income (loss) from discontinued operations, net of tax	100	162	213	192	113	211	244	277	667	845	741
Undistributed income of bank subsidiaries									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net income (loss)	1,400	384	(898)	310	(206)	(210)	113	146	1,196	(157)	1,029
Intercompany [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest and dividends on available-for-sale investment securities											0
Interest-bearing cash									0
Interest Expense, Debt									0	0	0
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									852	1,071	938
Interest on loans held-for-sale									15	5	75
Interest on trading assets									0	0	0
Interest and dividends on available-for-sale investment securities									0	4	4
Interest-bearing cash									16	5	13
Operating leases									232	713	1,063
Total financing revenue and other interest income									1,231	2,011	2,616
Interest on deposits									58	65	52
Interest on short-term borrowings									60	56	43
Interest on long-term debt									2,688	3,405	3,735
Total interest expense									2,805	3,513	3,809
Depreciation expense on operating lease assets									113	250	435
Net financing revenue (loss)									(1,687)	(1,752)	(1,628)
Nonbank subsidiaries									1,074	1,383	182
Servicing fees									191	270	434
Servicing asset valuation and hedge activities, net									0	0	0
Total servicing income, net									191	270	434
Insurance premiums and service revenue earned									0	0	0
Gain (loss) on mortgage and automotive loans, net									(2)	22	31
Gain (loss) on extinguishment of debt									0	(64)	(127)
Other gain (loss) on investments, net									0	10	6
Other income, net of losses									173	(167)	(151)
Total other revenue									362	71	193
Total net revenue (loss)									(251)	(298)	(1,253)
Provision for loan losses									81	58	(200)
Compensation and benefits expense									760	694	785
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									1,128	546	744
Total noninterest expense									1,888	1,240	1,529
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									(2,220)	(1,596)	(2,582)
Income tax expense (benefit) from continuing operations									(172)	(616)	(574)
Net income (loss) from continuing operations									(2,048)	(980)	(2,008)
Income (loss) from discontinued operations, net of tax									119	24	150
Undistributed income of bank subsidiaries									859	1,254	902
Undistributed income of nonbank subsidiaries									2,266	(455)	1,985
Net income (loss)									1,196	(157)	1,029
Parent [Member] | Intercompany [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									116	213	411
Interest and dividends on available-for-sale investment securities											112
Interest-bearing cash									0
Interest Expense, Debt									(1)	(13)	(21)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest on loans held-for-sale									0	0	0
Interest on trading assets									0	0	0
Interest and dividends on available-for-sale investment securities									0	0	0
Interest-bearing cash									0	0	0
Operating leases									0	0	0
Total financing revenue and other interest income									0	0	0
Interest on deposits									0	0	0
Interest on short-term borrowings									0	0	0
Interest on long-term debt									0	(1)	(1)
Total interest expense									1	1	1
Depreciation expense on operating lease assets									0	0	0
Net financing revenue (loss)									(1)	(1)	(1)
Nonbank subsidiaries									448	0	1
Servicing fees									0	0	0
Servicing asset valuation and hedge activities, net									0	0	0
Total servicing income, net									0	0	0
Insurance premiums and service revenue earned									0	0	0
Gain (loss) on mortgage and automotive loans, net									0	0	0
Gain (loss) on extinguishment of debt									0	0	0
Other gain (loss) on investments, net									0	0	0
Other income, net of losses									474	37	0
Total other revenue									474	37	0
Total net revenue (loss)									921	36	0
Provision for loan losses									0	0	0
Compensation and benefits expense									473	37	0
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									1	1	0
Total noninterest expense									474	38	0
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									447	(2)	0
Income tax expense (benefit) from continuing operations									0	(1)	0
Net income (loss) from continuing operations									447	(1)	0
Income (loss) from discontinued operations, net of tax									(93)	(8)	3
Undistributed income of bank subsidiaries									859	1,254	902
Undistributed income of nonbank subsidiaries									(105)	477	259
Net income (loss)									1,108	1,722	1,164
Guarantor Subsidiaries [Member] | Intercompany [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	0	0
Interest and dividends on available-for-sale investment securities											0
Interest-bearing cash									0
Interest Expense, Debt									1	2	2
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									3,751	3,348	3,538
Interest on loans held-for-sale									140	327	512
Interest on trading assets									13	19	15
Interest and dividends on available-for-sale investment securities									292	347	321
Interest-bearing cash									10	16	21
Operating leases									2,147	1,216	1,520
Total financing revenue and other interest income									6,391	5,299	5,940
Interest on deposits									586	549	527
Interest on short-term borrowings									30	60	98
Interest on long-term debt									795	926	1,026
Total interest expense									1,543	1,771	2,068
Depreciation expense on operating lease assets									1,286	691	816
Net financing revenue (loss)									3,562	2,837	3,056
Nonbank subsidiaries									0	0	0
Servicing fees									510	1,089	1,055
Servicing asset valuation and hedge activities, net									(8)	(789)	(394)
Total servicing income, net									502	300	661
Insurance premiums and service revenue earned									1,059	1,170	1,371
Gain (loss) on mortgage and automotive loans, net									534	448	1,208
Gain (loss) on extinguishment of debt									(148)	0	(9)
Other gain (loss) on investments, net									146	249	502
Other income, net of losses									1,290	1,287	1,046
Total other revenue									3,383	3,454	4,779
Total net revenue (loss)									6,945	6,291	7,835
Provision for loan losses									248	130	557
Compensation and benefits expense									608	628	563
Insurance losses and loss adjustment expenses									461	483	547
Other operating expenses									3,083	3,017	2,930
Total noninterest expense									4,152	4,128	4,040
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									2,545	2,033	3,238
Income tax expense (benefit) from continuing operations									(1,112)	668	678
Net income (loss) from continuing operations									3,657	1,365	2,560
Income (loss) from discontinued operations, net of tax									641	826	592
Undistributed income of bank subsidiaries									0	0	0
Undistributed income of nonbank subsidiaries									0	0	0
Net income (loss)									4,298	2,191	3,152
Non-Guarantor Subsidiaries [Member] | Intercompany [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									22	26	4
Interest and dividends on available-for-sale investment securities											9
Interest-bearing cash									16
Interest Expense, Debt									132	236	417
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									0	(10)	(1)
Interest on loans held-for-sale									0	0	0
Interest on trading assets									0	0	0
Interest and dividends on available-for-sale investment securities									0	0	(2)
Interest-bearing cash									0	0	0
Operating leases									0	0	0
Total financing revenue and other interest income									(154)	(249)	(539)
Interest on deposits									0	0	0
Interest on short-term borrowings									0	0	0
Interest on long-term debt									(17)	(21)	(20)
Total interest expense									(149)	(246)	(418)
Depreciation expense on operating lease assets									0	0	0
Net financing revenue (loss)									(5)	(3)	(121)
Nonbank subsidiaries									(1,522)	(1,383)	(183)
Servicing fees									0	(1)	(1)
Servicing asset valuation and hedge activities, net									0	0	0
Total servicing income, net									0	(1)	(1)
Insurance premiums and service revenue earned									0	0	0
Gain (loss) on mortgage and automotive loans, net									0	0	0
Gain (loss) on extinguishment of debt									0	0	12
Other gain (loss) on investments, net									0	0	(6)
Other income, net of losses									(1,190)	(664)	(561)
Total other revenue									(1,190)	(665)	(556)
Total net revenue (loss)									(2,717)	(2,051)	(860)
Provision for loan losses									0	0	0
Compensation and benefits expense									(476)	(37)	0
Insurance losses and loss adjustment expenses									0	0	0
Other operating expenses									(714)	(628)	(596)
Total noninterest expense									(1,190)	(665)	(596)
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries									(1,527)	(1,386)	(264)
Income tax expense (benefit) from continuing operations									0	0	0
Net income (loss) from continuing operations									(1,527)	(1,386)	(264)
Income (loss) from discontinued operations, net of tax									0	3	(4)
Undistributed income of bank subsidiaries									(1,718)	(2,508)	(1,804)
Undistributed income of nonbank subsidiaries									(2,161)	(22)	(2,244)
Net income (loss)									(5,406)	(3,913)	(4,316)
Consolidation, Eliminations [Member] | Intercompany [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and fees on finance receivables and loans									(138)	(239)	(415)
Interest and dividends on available-for-sale investment securities											(121)
Interest-bearing cash									(16)
Interest Expense, Debt									$ (132)	$ (225)	$ (398)