Finance Receivables and Loans, Net (Finance receivables and loans redefaulted during the period) (Details) - Consumer portfolio segment $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Accounts, Notes, Loans and Financing Receivable
Financing receivable, modifications, subsequent default, number of loans	7,215	9,713	8,832,000,000
Financing receivable, modifications, subsequent default, gross carrying value	$ 81	$ 111	$ 103
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 52	$ 73	$ 71
Automotive loan
Accounts, Notes, Loans and Financing Receivable
Financing receivable, modifications, subsequent default, number of loans	7,215	9,711	8,829,000,000
Financing receivable, modifications, subsequent default, gross carrying value	$ 81	$ 111	$ 102
Financing receivables, impaired, troubled debt restructuring, charge-off amount	$ 52	$ 73	$ 71
Mortgage Finance operations
Accounts, Notes, Loans and Financing Receivable
Financing receivable, modifications, subsequent default, number of loans			1,000,000
Financing receivable, modifications, subsequent default, gross carrying value			$ 1
Financing receivables, impaired, troubled debt restructuring, charge-off amount			$ 0
Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable
Financing receivable, modifications, subsequent default, number of loans		2	2,000,000
Financing receivable, modifications, subsequent default, gross carrying value		$ 0	$ 0
Financing receivables, impaired, troubled debt restructuring, charge-off amount		$ 0	$ 0

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Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524

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Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
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Reflects the amount of the write-down related to a troubled debt restructuring.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 310
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