Segment And Geographic Information (Financial Information Operating Segments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net financing revenue (loss)	$ 951	$ 850
Other revenue	376	243
Total net revenue (loss)	1,327	1,093
Provision for loan losses	220	116
Total noninterest expense	710	695
Income (loss) from continuing operations before income tax expense	397	282
Assets	156,505	153,324	$ 158,581
Net Interest Income (Loss) after Provision for Loan Losses	731	734
Automotive Finance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	896	809
Other revenue	77	52
Total net revenue (loss)	973	861
Provision for loan losses	209	127
Total noninterest expense	427	428
Income (loss) from continuing operations before income tax expense	337	306
Assets	112,289	111,149
Insurance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	14	12
Other revenue	254	268
Total net revenue (loss)	268	280
Provision for loan losses	0	0
Total noninterest expense	218	202
Income (loss) from continuing operations before income tax expense	50	78
Assets	7,194	7,242
Mortgage Finance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	20	11
Other revenue	0	0
Total net revenue (loss)	20	11
Provision for loan losses	3	2
Total noninterest expense	15	8
Income (loss) from continuing operations before income tax expense	2	1
Assets	7,493	3,941
Corporate Finance Operations [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	28	20
Other revenue	6	6
Total net revenue (loss)	34	26
Provision for loan losses	6	(5)
Total noninterest expense	17	14
Income (loss) from continuing operations before income tax expense	11	17
Assets	2,839	1,976
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Net financing revenue (loss)	(7)	(2)
Other revenue	39	(83)
Total net revenue (loss)	32	(85)
Provision for loan losses	2	(8)
Total noninterest expense	33	43
Income (loss) from continuing operations before income tax expense	(3)	(120)
Assets	$ 26,690	$ 29,016