Discontinued Operation, Amounts of General Unsecured Claims, Amount

No definition available.

Name:	gm_DiscontinuedOperationAmountsofGeneralUnsecuredClaimsAmount
Namespace Prefix:	gm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discontinued Operation, Amounts of Material Contingent Liabilities Remaining, Shares Issuable

+ References

No definition available.

+ Details

Name:	gm_DiscontinuedOperationAmountsofMaterialContingentLiabilitiesRemainingSharesIssuable
Namespace Prefix:	gm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Discontinued Operation, Material Contingent Liabilities, General Unsecured Claims, Threshold Amount

+ References

No definition available.

+ Details

Name:	gm_DiscontinuedOperationMaterialContingentLiabilitiesGeneralUnsecuredClaimsThresholdAmount
Namespace Prefix:	gm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Estimated potential recovery from the taxing authority.

+ References

No definition available.

+ Details

Name:	gm_LossContingencyEstimatedPotentialRecoveryFromTaxingAuthority
Namespace Prefix:	gm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of shareholders filing an appeal of the decision approving the settlement.

+ References

No definition available.

+ Details

Name:	gm_LossContingencyNumberofShareholdersFilinganAppeal
Namespace Prefix:	gm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss Contingency, Number of States

+ References

No definition available.

+ Details

Name:	gm_LossContingencyNumberofStates
Namespace Prefix:	gm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Period after the expiration of deferral-of-prosecution period, during which a dismissal of the prosecution can occur.

+ References

No definition available.

+ Details

Name:	gm_LossContingencyPeriodaftertheexpirationoftheperiodofdeferral
Namespace Prefix:	gm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the deferral-of-prosecution period.

+ References

No definition available.

+ Details

Name:	gm_LossContingencyProsecutionDeferralPeriod
Namespace Prefix:	gm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of employee involved in the case related to which supreme court rendered its decision.

+ References

No definition available.

+ Details

Name:	gm_NumberofEmployeeintheCase
Namespace Prefix:	gm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs.

+ References

+ Details

Name:	us-gaap_LitigationReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of damages paid to the plaintiff in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349

+ Details

Name:	us-gaap_LossContingencyDamagesPaidValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total number of new claims filed pertaining to a loss contingency during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

+ Details

Name:	us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of plaintiffs that have filed claims pertaining to a loss contingency.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingencyNumberOfPlaintiffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of pending claims pertaining to a loss contingency.

+ References

+ Details

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 05
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6395354&loc=d3e12631-108344

+ Details

Name:	us-gaap_LossContingencyRangeOfPossibleLossPortionNotAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=gm_IndirectTaxMattersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=gm_TexasStateMultiJurisdictionalLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=us-gaap_PendingLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_BR
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_ForeignCountryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_IgnitionSwitchRecallLitigationsEconomicDamageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_IgnitionSwitchRecallLitigationsJuly2009SaleOrderMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=gm_GrantedMotiontoDismissMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_IgnitionSwitchRecallLitigationsShareholderClassActionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_IgnitionSwitchRecallLitigationsShareholderDerivativeActionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=gm_EasternDistrictofMichiganMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=gm_ConsolidatedLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=gm_WayneCountyMichiganMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_IgnitionSwitchRecallLitigationsInvestigationbytheOfficeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_KoreaWageLitigationHourlyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_KoreaWageLitigationSalariedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_KoreaWageLitigationFormerSubcontractWorkersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=gm_AccruedLiabilitiesCurrentandOtherLiabilitiesNoncurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=gm_AmendedandRestatedMasterSaleandPurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=gm_IgnitionSwitchRecallLitigationsContingentlyIssuableSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies Litigation-Related Liability and Tax Administrative Matters (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2015 USD ($)	Mar. 31, 2018 USD ($) case action employee shareholder shares	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) state	Aug. 31, 2017 state
Indirect Tax Matters [Member]
Loss Contingencies [Line Items]
Estimate of possible loss		$ 1,000,000,000
Texas state (MDL) [Member] \| Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of additional bellwether trials \| case		2
Brazil [Member] \| Foreign Tax Authority [Member]
Loss Contingencies [Line Items]
Estimated potential recovery		$ 1,400,000,000
Ignition Switch Recall Litigations - Economic-loss cases [Member]
Loss Contingencies [Line Items]
Number of pending claims \| action		100
Ignition Switch Recall Litigations - July 2009 Sale Order [Member]
Loss Contingencies [Line Items]
Number of states \| state					16
Ignition Switch Recall Litigations - July 2009 Sale Order [Member] \| Granted Motion to Dismiss [Member]
Loss Contingencies [Line Items]
Number of states \| state					7
Ignition Switch Recall Litigations - July 2009 Sale Order [Member] \| Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of states \| state				8	9
Ignition Switch Recall Litigations - Shareholder Class Action [Member]
Loss Contingencies [Line Items]
Litigation settlement amount			$ 300,000,000
Number of shareholders filing an appeal \| shareholder		1
Ignition Switch Recall Litigations - Shareholder Derivative Action [Member] \| Eastern District of Michigan [Member] \| Consolidated Litigation [Member]
Loss Contingencies [Line Items]
Number of pending claims \| case		3
Ignition Switch Recall Litigations - Shareholder Derivative Action [Member] \| Wayne County, Michigan [Member] \| Consolidated Litigation [Member]
Loss Contingencies [Line Items]
Number of pending claims \| case		2
Ignition Switch Recall Litigations - Investigation by the Office [Member]
Loss Contingencies [Line Items]
Damages paid	$ 900,000,000
Prosecution deferral period	3 years
Period after the expiration of the period of deferral	30 days
Korea Wage Litigation - Hourly [Member]
Loss Contingencies [Line Items]
Number of plaintiffs \| employee		10,000
Number of employees in the case \| employee		5
Estimate of possible loss		$ 600,000,000
Korea Wage Litigation - Salaried [Member]
Loss Contingencies [Line Items]
Estimate of possible loss		200,000,000
Korea Wage Litigation - Former Subcontract Workers [Member]
Loss Contingencies [Line Items]
Estimate of possible loss		150,000,000
Accrued liabilities and Other liabilities [Member]
Loss Contingencies [Line Items]
Estimated litigation liability		941,000,000		$ 930,000,000
Amended and Restated Master Sale and Purchase Agreement [Member] \| Ignition Switch Recall Litigations - Contingently Issuable Shares [Member]
Loss Contingencies [Line Items]
Allowed general unsecured claims amount		$ 35,000,000,000.0
Contingently issuable shares (in shares) \| shares		30,000,000
Amount of allowed general unsecured claims		$ 31,900,000,000