GM Financial Receivables and Transactions Retail Finance Receivables Delinquencies and TDRs (Details) - GM Financial [Member] $ in Millions	Sep. 30, 2018 USD ($) score	Dec. 31, 2017 USD ($) score	Sep. 30, 2017 USD ($)
Delinquent Contracts [Abstract]
Finance receivables, individually evaluated for impairment, net of fees	$ 2,375	$ 2,250
Allowance for loan losses - TDRs	$ 325	$ 331
Retail Finance Receivables [Member]
Financing Receivable, Recorded Investment, Additional Information [Abstract]
Percentage of receivables with sub-prime credit scores	27.00%	33.00%
Sub-prime FICO score \| score	620	620
Retail finance receivables, nonaccrual status	$ 847	$ 778
Delinquent Contracts [Abstract]
Past Due Amount	$ 1,853		$ 1,752
Percent of Contractual Amount Due	4.90%		5.40%
Finance receivables, individually evaluated for impairment, net of fees	$ 2,308	2,228
Allowance for loan losses - TDRs	317	$ 328
31-to-60 days delinquent [Member] \| Retail Finance Receivables [Member]
Delinquent Contracts [Abstract]
Past Due Amount	$ 1,302		$ 1,176
Percent of Contractual Amount Due	3.50%		3.60%
Greater-than-60 days delinquent [Member] \| Retail Finance Receivables [Member]
Delinquent Contracts [Abstract]
Past Due Amount	$ 498		$ 521
Percent of Contractual Amount Due	1.30%		1.60%
Total finance receivables more than 30 days delinquent [Member] \| Retail Finance Receivables [Member]
Delinquent Contracts [Abstract]
Past Due Amount	$ 1,800		$ 1,697
Percent of Contractual Amount Due	4.80%		5.20%
In repossession [Member] \| Retail Finance Receivables [Member]
Delinquent Contracts [Abstract]
Past Due Amount	$ 53		$ 55
Percent of Contractual Amount Due	0.10%		0.20%

Financing Receivable, Recorded Investment, Additional Information [Abstract]

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- Definition

Sub-prime loans as percentage of the total loans.

+ References

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- Definition

The FICO score used to separate sub-prime from prime loans. The loans with a borrower that has less then this score will be considered as sub-prime.

+ References

No definition available.

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- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

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-Publisher FASB
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-Topic 310
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-Paragraph 11B
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- Definition

Percentage of financing receivable balance that is past due.

+ References

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

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-Publisher FASB
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- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

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- References

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