Finance Receivables and Loans, Net (Schedule of Average Balance and Interest Income of Impaired Finance Receivables) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	$ 905	$ 775	$ 852	$ 746
Financing receivable, impaired, interest income	10	8	31	32
Consumer portfolio segment \| Consumer loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	714	628	706	612
Financing receivable, impaired, interest income	10	7	29	22
Consumer portfolio segment \| Automobile loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	485	389	477	368
Financing receivable, impaired, interest income	7	5	21	15
Consumer portfolio segment \| Residential mortgage
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	229	239	229	244
Financing receivable, impaired, interest income	3	2	8	7
Consumer portfolio segment \| Mortgage Finance
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	12	8	10	8
Financing receivable, impaired, interest income	1	0	1	0
Consumer portfolio segment \| Mortgage - Legacy
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	217	231	219	236
Financing receivable, impaired, interest income	2	2	7	7
Commercial portfolio segment \| Commercial loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	191	147	146	134
Financing receivable, impaired, interest income	0	1	2	10
Commercial portfolio segment \| Commercial and industrial automotive
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	83	77	65	55
Financing receivable, impaired, interest income	0	1	2	2
Commercial portfolio segment \| Commercial and industrial other
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	101	63	76	73
Financing receivable, impaired, interest income	0	0	0	8
Commercial portfolio segment \| Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	7	7	5	6
Financing receivable, impaired, interest income	$ 0	$ 0	$ 0	$ 0

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No definition available.

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&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.

+ References

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