Parent And Guarantor Consolidating Financial Statements (Schedule of Consolidating Statement of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		$ 1,114	$ 1,119	$ 3,345	$ 3,393
Interest on loans held-for-sale		0	0	1	19
Interest and dividends on available-for-sale investment securities		94	85	282	229
Interest-bearing cash		2	3	6	8
Operating leases		899	832	2,653	2,354
Total financing revenue and other interest income		2,109	2,039	6,287	6,003
Interest on deposits		166	163	495	489
Interest on short-term borrowings		12	15	40	47
Interest on long-term debt		493	609	1,576	2,013
Interest Expense, Debt		0	0	0	0
Total interest expense		671	787	2,111	2,549
Depreciation expense on operating lease assets		549	515	1,600	1,449
Net financing revenue (loss)		889	737	2,576	2,005
Bank Subsidiary		0		0
Nonbank subsidiaries		0	0	0	0
Servicing fees		6	13	22	114
Servicing asset valuation and hedge activities, net		0	0	0	(213)
Total servicing income, net		6	13	22	(99)
Insurance premiums and service revenue earned		246	251	736	768
Gain (loss) on mortgage and automotive loans, net		0	15	6	52
Gains (Losses) on Extinguishment of Debt	(160)	0	(42)	(46)	(42)
Other gain (loss) on investments, net		45	41	129	156
Other income, net of losses		78	93	214	324
Total other revenue		375	371	1,061	1,159
Total net revenue (loss)		1,264	1,108	3,637	3,164
Provision for loan losses		102	141	302	361
Compensation and benefits expense		241	245	710	782
Insurance losses and loss adjustment expenses		97	85	353	346
Other operating expenses		404	432	1,213	1,393
Total noninterest expense		742	762	2,276	2,521
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries		420	205	1,059	282
Income tax expense (benefit) from continuing operations		127	28	285	(55)
Net income (loss) from continuing operations		293	177	774	337
Income (loss) from discontinued operations, net of tax		130	(86)	199	(80)
Undistributed income of bank subsidiaries		0	0	0	0
Undistributed income of nonbank subsidiaries		0	0	0	0
Net income (loss)		423	91	973	257
Other comprehensive income (loss), net of tax		(55)	4	126	(494)
Comprehensive income (loss)		368	95	1,099	(237)
Parent [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		16	243	(2)	674
Interest on loans held-for-sale				0	0
Interest and dividends on available-for-sale investment securities		0	0	0	0
Interest-bearing cash		0	1	1	3
Operating leases		1	141	269	355
Total financing revenue and other interest income		27	397	294	1,081
Interest on deposits		3	5	11	20
Interest on short-term borrowings		10	11	32	35
Interest on long-term debt		350	469	1,143	1,593
Interest Expense, Debt		22	23	68	43
Total interest expense		385	508	1,254	1,691
Depreciation expense on operating lease assets		(4)	103	164	267
Net financing revenue (loss)		(354)	(214)	(1,124)	(877)
Bank Subsidiary		150		1,650
Nonbank subsidiaries		141	54	462	5,217
Servicing fees		6	36	22	118
Servicing asset valuation and hedge activities, net		0	0	0	0
Total servicing income, net		6	36	22	118
Insurance premiums and service revenue earned		0	0	0	0
Gain (loss) on mortgage and automotive loans, net		(2)	0	(2)	0
Gains (Losses) on Extinguishment of Debt			(42)	(46)	(42)
Other gain (loss) on investments, net		0	0	0	0
Other income, net of losses		206	51	591	128
Total other revenue		210	45	565	204
Total net revenue (loss)		147	(115)	1,553	4,544
Provision for loan losses		88	69	165	298
Compensation and benefits expense		153	153	441	505
Insurance losses and loss adjustment expenses		0	0	0	0
Other operating expenses		252	119	648	274
Total noninterest expense		405	272	1,089	779
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries		(346)	(456)	299	3,467
Income tax expense (benefit) from continuing operations		(68)	(189)	(309)	(748)
Net income (loss) from continuing operations		(278)	(267)	608	4,215
Income (loss) from discontinued operations, net of tax		127	142	172	(1,365)
Undistributed income of bank subsidiaries		150	235	(802)	668
Undistributed income of nonbank subsidiaries		424	(19)	995	(3,261)
Net income (loss)		423	91	973	257
Other comprehensive income (loss), net of tax		(55)	4	126	(494)
Comprehensive income (loss)		368	95	1,099	(237)
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		0	0	0	0
Interest on loans held-for-sale				0	0
Interest and dividends on available-for-sale investment securities		0	0	0	0
Interest-bearing cash		0	0	0	0
Operating leases		0	0	0	0
Total financing revenue and other interest income		0	0	0	0
Interest on deposits		0	0	0	0
Interest on short-term borrowings		0	0	0	0
Interest on long-term debt		0	0	0	0
Interest Expense, Debt		0	0	0	0
Total interest expense		0	0	0	0
Depreciation expense on operating lease assets		0	0	0	0
Net financing revenue (loss)		0	0	0	0
Bank Subsidiary		150		1,650
Nonbank subsidiaries		0	0	0	3,659
Servicing fees		0	0	0	0
Servicing asset valuation and hedge activities, net		0	0	0	0
Total servicing income, net		0	0	0	0
Insurance premiums and service revenue earned		0	0	0	0
Gain (loss) on mortgage and automotive loans, net		0	0	0	0
Gains (Losses) on Extinguishment of Debt			0	0	0
Other gain (loss) on investments, net		0	0	0	0
Other income, net of losses		0	0	0	0
Total other revenue		0	0	0	0
Total net revenue (loss)		150	0	1,650	3,659
Provision for loan losses		0	0	0	0
Compensation and benefits expense		0	0	0	0
Insurance losses and loss adjustment expenses		0	0	0	0
Other operating expenses		0	0	0	0
Total noninterest expense		0	0	0	0
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries		150	0	1,650	3,659
Income tax expense (benefit) from continuing operations		0	0	0	0
Net income (loss) from continuing operations		150	0	1,650	3,659
Income (loss) from discontinued operations, net of tax		0	15	0	(19)
Undistributed income of bank subsidiaries		150	235	(802)	668
Undistributed income of nonbank subsidiaries		(2)	5	(2)	(2,395)
Net income (loss)		298	255	846	1,913
Other comprehensive income (loss), net of tax		(3)	(34)	116	(753)
Comprehensive income (loss)		295	221	962	1,160
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		1,098	876	3,347	2,719
Interest on loans held-for-sale				1	19
Interest and dividends on available-for-sale investment securities		94	85	282	229
Interest-bearing cash		2	2	5	5
Operating leases		898	691	2,384	1,999
Total financing revenue and other interest income		2,114	1,677	6,087	5,023
Interest on deposits		163	158	484	469
Interest on short-term borrowings		2	4	8	12
Interest on long-term debt		143	140	433	425
Interest Expense, Debt		10	12	26	52
Total interest expense		318	314	951	958
Depreciation expense on operating lease assets		553	412	1,436	1,182
Net financing revenue (loss)		1,243	951	3,700	2,883
Bank Subsidiary		0		0
Nonbank subsidiaries		0	0	0	0
Servicing fees		0	(23)	0	(4)
Servicing asset valuation and hedge activities, net		0	0	0	(213)
Total servicing income, net		0	(23)	0	(217)
Insurance premiums and service revenue earned		246	251	736	768
Gain (loss) on mortgage and automotive loans, net		2	15	8	52
Gains (Losses) on Extinguishment of Debt			0	0	0
Other gain (loss) on investments, net		45	41	129	156
Other income, net of losses		373	350	1,007	1,116
Total other revenue		666	634	1,880	1,875
Total net revenue (loss)		1,909	1,585	5,580	4,758
Provision for loan losses		14	72	137	63
Compensation and benefits expense		199	205	604	622
Insurance losses and loss adjustment expenses		97	85	353	346
Other operating expenses		542	508	1,614	1,694
Total noninterest expense		838	798	2,571	2,662
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries		1,057	715	2,872	2,033
Income tax expense (benefit) from continuing operations		195	217	594	693
Net income (loss) from continuing operations		862	498	2,278	1,340
Income (loss) from discontinued operations, net of tax		3	(243)	27	1,303
Undistributed income of bank subsidiaries		0	0	0	0
Undistributed income of nonbank subsidiaries		0	0	0	0
Net income (loss)		865	255	2,305	2,643
Other comprehensive income (loss), net of tax		(50)	24	124	(830)
Comprehensive income (loss)		815	279	2,429	1,813
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		0	0	0	0
Interest on loans held-for-sale				0	0
Interest and dividends on available-for-sale investment securities		0	0	0	0
Interest-bearing cash		0	0	0	0
Operating leases		0	0	0
Total financing revenue and other interest income		(32)	(35)	(94)	(101)
Interest on deposits		0	0	0	0
Interest on short-term borrowings		0	0	0	0
Interest on long-term debt		0	0	0	(5)
Interest Expense, Debt		(32)	(35)	(94)	(95)
Total interest expense		(32)	(35)	(94)	(100)
Depreciation expense on operating lease assets		0	0	0	0
Net financing revenue (loss)		0	0	0	(1)
Bank Subsidiary		(300)		(3,300)
Nonbank subsidiaries		(141)	(54)	(462)	(8,876)
Servicing fees		0	0	0	0
Servicing asset valuation and hedge activities, net		0	0	0	0
Total servicing income, net		0	0	0	0
Insurance premiums and service revenue earned		0	0	0	0
Gain (loss) on mortgage and automotive loans, net		0	0	0	0
Gains (Losses) on Extinguishment of Debt			0	0	0
Other gain (loss) on investments, net		0	0	0	0
Other income, net of losses		(501)	(308)	(1,384)	(920)
Total other revenue		(501)	(308)	(1,384)	(920)
Total net revenue (loss)		(942)	(362)	(5,146)	(9,797)
Provision for loan losses		0	0	0	0
Compensation and benefits expense		(111)	(113)	(335)	(345)
Insurance losses and loss adjustment expenses		0	0	0	0
Other operating expenses		(390)	(195)	(1,049)	(575)
Total noninterest expense		(501)	(308)	(1,384)	(920)
(Loss) income from continuing operations before income tax (benefit) expense and undistributed income of subsidiaries		(441)	(54)	(3,762)	(8,877)
Income tax expense (benefit) from continuing operations		0	0	0	0
Net income (loss) from continuing operations		(441)	(54)	(3,762)	(8,877)
Income (loss) from discontinued operations, net of tax		0	0	0	1
Undistributed income of bank subsidiaries		(300)	(470)	1,604	(1,336)
Undistributed income of nonbank subsidiaries		(422)	14	(993)	5,656
Net income (loss)		(1,163)	(510)	(3,151)	(4,556)
Other comprehensive income (loss), net of tax		53	10	(240)	1,583
Comprehensive income (loss)		(1,110)	(500)	(3,391)	(2,973)
Intercompany [Member] | Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating leases					0
Affiliated Entity [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		0	0	0	0
Interest-bearing cash		0	0	0	0
Affiliated Entity [Member] | Parent [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		10	12	26	49
Interest-bearing cash		0	0	0	0
Affiliated Entity [Member] | Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		0	0	0	0
Interest-bearing cash		0	0	0	0
Affiliated Entity [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		21	21	64	46
Interest-bearing cash		1	2	4	6
Affiliated Entity [Member] | Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Interest and fees on finance receivables and loans		(31)	(33)	(90)	(95)
Interest-bearing cash		$ (1)	$ (2)	$ (4)	$ (6)