Finance Receivables And Loans, Net (Average Balance And Interest Income Of Impaired Finance Receivables) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 643	$ 1,297	$ 653	$ 1,358
Impaired Financing Receivable, Interest Income, Accrual Method	7	12	24	41
Consumer Portfolio Segment [Member] \| Automobile Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	288	297	291	298
Impaired Financing Receivable, Interest Income, Accrual Method	4	5	13	14
Consumer Portfolio Segment [Member] \| Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	268	914	283	923
Impaired Financing Receivable, Interest Income, Accrual Method	3	7	7	22
Commercial Portfolio Segment [Member] \| Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	87	86	79	137
Impaired Financing Receivable, Interest Income, Accrual Method	0	0	4	5
Commercial Portfolio Segment [Member] \| Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	36	32	35	68
Impaired Financing Receivable, Interest Income, Accrual Method	0	0	1	1
Commercial Portfolio Segment [Member] \| Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	45	51	39	62
Impaired Financing Receivable, Interest Income, Accrual Method	0	0	3	4
Commercial Portfolio Segment [Member] \| Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	6	3	5	7
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0	$ 0	$ 0

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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