Finance Receivables and Loans, Net (Schedule of Average Balance and Interest Income of Impaired Finance Receivables) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	$ 1,033	$ 776
Financing receivable, impaired, interest income	12	10
Consumer portfolio segment \| Consumer loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	728	674
Financing receivable, impaired, interest income	11	9
Consumer portfolio segment \| Automobile loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	499	444
Financing receivable, impaired, interest income	8	7
Consumer portfolio segment \| Residential mortgage
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	229	230
Financing receivable, impaired, interest income	3	2
Consumer portfolio segment \| Mortgage Finance
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	15	9
Financing receivable, impaired, interest income	0	0
Consumer portfolio segment \| Mortgage - Legacy
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	214	221
Financing receivable, impaired, interest income	3	2
Commercial portfolio segment \| Commercial loan
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	305	102
Financing receivable, impaired, interest income	1	1
Commercial portfolio segment \| Commercial and industrial automotive
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	170	47
Financing receivable, impaired, interest income	1	1
Commercial portfolio segment \| Commercial and industrial other
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	130	52
Financing receivable, impaired, interest income	0	0
Commercial portfolio segment \| Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, impaired, average balance	5	3
Financing receivable, impaired, interest income	$ 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://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.

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