Finance Receivables and Loans, Net (Finance Receivables and Loans Redefaulted During the Period) (Details) - Consumer $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) loan	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) loan
Accounts, Notes, Loans and Financing Receivable
Number of loans \| loan	2,374	5,195	6,944	7,478
Amortized cost	$ 31	$ 52	$ 86	$ 76
Charge-off amount	$ 15	$ 37	$ 46	$ 54
Automotive loan
Accounts, Notes, Loans and Financing Receivable
Number of loans \| loan	2,374	5,195	6,939	7,478
Amortized cost	$ 31	$ 52	$ 86	$ 76
Charge-off amount	$ 15	$ 37	$ 46	$ 54
Mortgage Finance
Accounts, Notes, Loans and Financing Receivable
Number of loans \| loan			1	0
Amortized cost			$ 0	$ 0
Charge-off amount			$ 0	$ 0
Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable
Number of loans \| loan			4	0
Amortized cost			$ 0	$ 0
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=123577603&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
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953682-111524

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- Definition

Reflects the amount of the write-down related to a troubled debt restructuring.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554

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