Debt - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended
Apr. 30, 2021	Mar. 31, 2021
Unsecured Debt \| Line of Credit \| Subsequent Event
Debt Instrument [Line Items]
Aggregate borrowing capacity	$ 11,200,000,000
Unsecured Debt \| Line of Credit \| Five Year Revolving Credit Facility Due 2023
Debt Instrument [Line Items]
Debt term		5 years
Aggregate borrowing capacity		$ 10,500,000,000
Unsecured Debt \| Line of Credit \| Five Year Revolving Credit Facility Due 2023 \| Subsequent Event
Debt Instrument [Line Items]
Debt term	5 years
Unsecured Debt \| Line of Credit \| Five Year Revolving Credit Facility Due 2026 \| Subsequent Event
Debt Instrument [Line Items]
Debt term	5 years
Aggregate borrowing capacity	$ 9,900,000,000
Line of credit extension period	3 years
Unsecured Debt \| Line of Credit \| Three Year Revolving Credit Facility April 2024 \| Subsequent Event
Debt Instrument [Line Items]
Debt term	3 years
Aggregate borrowing capacity	$ 4,300,000,000
Unsecured Debt \| Line of Credit \| Three Year Revolving Credit Facility April 2021
Debt Instrument [Line Items]
Debt term		3 years
Aggregate borrowing capacity		$ 4,000,000,000.0
GM Financial \| Line of Credit
Debt Instrument [Line Items]
Aggregate borrowing capacity		$ 6,000,000,000.0
GM Financial \| Senior Notes \| Subsequent Event
Debt Instrument [Line Items]
Principal amount	$ 2,300,000,000
Weighted average interest rate (percent)	1.60%
GM Financial \| Unsecured Debt \| Line of Credit \| $2.0 Billion Dollar Revolving Credit Facility
Debt Instrument [Line Items]
Debt term		364 days
Aggregate borrowing capacity		$ 2,000,000,000.0
GM Financial \| Unsecured Debt \| Line of Credit \| $2.0 Billion Dollar Revolving Credit Facility \| Subsequent Event
Debt Instrument [Line Items]
Debt term	364 days
Aggregate borrowing capacity	$ 2,000,000,000.0
GM Financial \| Unsecured Debt \| Senior Notes
Debt Instrument [Line Items]
Principal amount		$ 3,800,000,000
Weighted average interest rate (percent)		1.44%
GM Financial \| Secured Debt \| Notes Payable, Other Payables \| Securitization notes payable
Debt Instrument [Line Items]
Principal amount		$ 8,200,000,000
Weighted average interest rate (percent)		0.82%

Line of Credit Facility, Extension Period

No definition available.

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Namespace Prefix:	gm_
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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Balance Type:	credit
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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