Segment And Geographic Information (Financial Information Operating Segments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net financing revenue (loss)	$ 850	$ 821
Other revenue	243	321
Total net revenue (loss)	1,093	1,142
Provision for loan losses	116	137
Total noninterest expense	695	713
Income (loss) from continuing operations before income tax expense	282	292
Assets	153,524	148,452	151,828
Net Interest Income (Loss) after Provision for Loan Losses	734	684
Automotive finance operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	809	820
Other revenue	52	64
Total net revenue (loss)	861	884
Provision for loan losses	127	159
Total noninterest expense	403	386
Income (loss) from continuing operations before income tax expense	331	339
Assets	111,149	109,307
Insurance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	12	15
Other revenue	268	272
Total net revenue (loss)	280	287
Provision for loan losses	0	0
Total noninterest expense	202	213
Income (loss) from continuing operations before income tax expense	78	74
Assets	7,242	7,184
Mortgage Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	15	14
Other revenue	68	4
Total net revenue (loss)	83	18
Provision for loan losses	(5)	(23)
Total noninterest expense	19	24
Income (loss) from continuing operations before income tax expense	69	17
Assets	7,694	7,937
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	14	(28)
Other revenue	(145)	(19)
Total net revenue (loss)	(131)	(47)
Provision for loan losses	(6)	1
Total noninterest expense	71	90
Income (loss) from continuing operations before income tax expense	(196)	(138)
Assets	27,439	24,024
Corporate Finance Operations [Member]
Segment Reporting Information [Line Items]
Assets	$ 2,000	$ 1,700