Consolidated Statement of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Financing Revenue and Other Interest Income [Abstract]
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 Expense [Abstract]
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
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
Other revenue [Abstract]
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
Noninterest Expense [Abstract]
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
Income (loss) from continuing operations before income tax expense		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)
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)
Earnings Per Share, Basic [Abstract]
Net income (loss) from continuing operations, Per Basic Share		$ 0.47	$ (0.06)	$ 1.19	$ (0.64)
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share		$ 0.27	$ (0.21)	$ 0.41	$ (0.19)
Net (loss) income, Basic		$ 0.74	$ (0.27)	$ 1.60	$ (0.83)
Earnings Per Share, Diluted [Abstract]
Net income (loss) from continuing operations, Per Diluted Share		$ 0.47	$ (0.06)	$ 1.19	$ (0.64)
Income (loss) from discontinued operations, net of tax		$ 0.27	$ (0.21)	$ 0.41	$ (0.19)
Net (loss) income, Diluted		$ 0.74	$ (0.27)	$ 1.60	$ (0.83)