Segment And Geographic Information (Financial Information Operating Segments) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net financing revenue (loss)	$ 640,000,000	$ 351,000,000
Other revenue	386,000,000	605,000,000
Total net revenue (loss)	1,026,000,000	956,000,000
Provision for loan losses	131,000,000	98,000,000
Total noninterest expense	958,000,000	855,000,000
Income (loss) from continuing operations before income tax expense	(63,000,000)	3,000,000
Assets	166,199,000,000	186,350,000,000	182,347,000,000
Net Interest Income (Loss) after Provision for Loan Losses	500,000,000	300,000,000
Automotive finance operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	773,000,000	630,000,000
Other revenue	82,000,000	77,000,000
Total net revenue (loss)	855,000,000	707,000,000
Provision for loan losses	112,000,000	78,000,000
Total noninterest expense	400,000,000	388,000,000
Income (loss) from continuing operations before income tax expense	343,000,000	241,000,000
Assets	118,882,000,000	119,081,000,000
Insurance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	12,000,000	12,000,000
Other revenue	308,000,000	338,000,000
Total net revenue (loss)	320,000,000	350,000,000
Provision for loan losses	0	0
Total noninterest expense	259,000,000	250,000,000
Income (loss) from continuing operations before income tax expense	61,000,000	100,000,000
Assets	8,331,000,000	8,394,000,000
Mortgage Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	34,000,000	37,000,000
Other revenue	(19,000,000)	137,000,000
Total net revenue (loss)	15,000,000	174,000,000
Provision for loan losses	20,000,000	27,000,000
Total noninterest expense	199,000,000	84,000,000
Income (loss) from continuing operations before income tax expense	(204,000,000)	63,000,000
Assets	11,284,000,000	30,079,000,000
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	(179,000,000)	(328,000,000)
Other revenue	15,000,000	53,000,000
Total net revenue (loss)	(164,000,000)	(275,000,000)
Provision for loan losses	(1,000,000)	(7,000,000)
Total noninterest expense	100,000,000	133,000,000
Income (loss) from continuing operations before income tax expense	(263,000,000)	(401,000,000)
Assets	27,702,000,000	28,796,000,000
Commercial Finance Operations [Member]
Segment Reporting Information [Line Items]
Assets	$ 1,400,000,000	$ 1,200,000,000