Segment And Geographic Information (Financial Information Operating Segments) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net financing revenue (loss)	$ 628,000,000	$ 457,000,000	$ 1,268,000,000	$ 808,000,000
Other revenue	402,000,000	714,000,000	788,000,000	1,319,000,000
Total net revenue (loss)	1,030,000,000	1,171,000,000	2,056,000,000	2,127,000,000
Provision for loan losses	89,000,000	33,000,000	220,000,000	131,000,000
Total noninterest expense	801,000,000	971,000,000	1,759,000,000	1,826,000,000
Income (loss) from continuing operations before income tax expense	140,000,000	167,000,000	77,000,000	170,000,000
Assets	150,627,000,000	178,560,000,000	150,627,000,000	178,560,000,000	182,347,000,000
Net Interest Income (Loss) after Provision for Loan Losses	500,000,000	400,000,000	1,000,000,000	700,000,000
Automotive finance operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	777,000,000	693,000,000	1,550,000,000	1,323,000,000
Other revenue	60,000,000	112,000,000	142,000,000	189,000,000
Total net revenue (loss)	837,000,000	805,000,000	1,692,000,000	1,512,000,000
Provision for loan losses	88,000,000	15,000,000	200,000,000	93,000,000
Total noninterest expense	367,000,000	350,000,000	767,000,000	738,000,000
Income (loss) from continuing operations before income tax expense	382,000,000	440,000,000	725,000,000	681,000,000
Assets	107,485,000,000	120,523,000,000	107,485,000,000	120,523,000,000
Insurance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	15,000,000	16,000,000	27,000,000	28,000,000
Other revenue	325,000,000	300,000,000	633,000,000	638,000,000
Total net revenue (loss)	340,000,000	316,000,000	660,000,000	666,000,000
Provision for loan losses	0	0	0	0
Total noninterest expense	295,000,000	296,000,000	554,000,000	546,000,000
Income (loss) from continuing operations before income tax expense	45,000,000	20,000,000	106,000,000	120,000,000
Assets	7,336,000,000	8,237,000,000	7,336,000,000	8,237,000,000
Mortgage Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	15,000,000	29,000,000	49,000,000	66,000,000
Other revenue	(6,000,000)	320,000,000	(25,000,000)	457,000,000
Total net revenue (loss)	9,000,000	349,000,000	24,000,000	523,000,000
Provision for loan losses	6,000,000	21,000,000	26,000,000	48,000,000
Total noninterest expense	46,000,000	226,000,000	245,000,000	310,000,000
Income (loss) from continuing operations before income tax expense	(43,000,000)	102,000,000	(247,000,000)	165,000,000
Assets	9,061,000,000	17,146,000,000	9,061,000,000	17,146,000,000
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	(179,000,000)	(281,000,000)	(358,000,000)	(609,000,000)
Other revenue	23,000,000	(18,000,000)	38,000,000	35,000,000
Total net revenue (loss)	(156,000,000)	(299,000,000)	(320,000,000)	(574,000,000)
Provision for loan losses	(5,000,000)	(3,000,000)	(6,000,000)	(10,000,000)
Total noninterest expense	93,000,000	99,000,000	193,000,000	232,000,000
Income (loss) from continuing operations before income tax expense	(244,000,000)	(395,000,000)	(507,000,000)	(796,000,000)
Assets	26,745,000,000	32,654,000,000	26,745,000,000	32,654,000,000
Commercial Finance Operations [Member]
Segment Reporting Information [Line Items]
Assets	$ 1,500,000,000	$ 1,200,000,000	$ 1,500,000,000	$ 1,200,000,000