XML 110 R89.htm IDEA: XBRL DOCUMENT v3.20.4

Pensions And Other Postretirement Benefits - Target Allocation tables (Details) - Pension Plan	Dec. 31, 2020	Dec. 31, 2019
U.S.
Defined Benefit Plan Disclosure [Line Items]
Target allocations	100.00%	100.00%
U.S. | Equity
Defined Benefit Plan Disclosure [Line Items]
Target allocations	12.00%	12.00%
U.S. | Corporate and other debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations	64.00%	64.00%
U.S. | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocations	24.00%	24.00%
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Target allocations	100.00%	100.00%
Non-U.S. | Equity
Defined Benefit Plan Disclosure [Line Items]
Target allocations	16.00%	14.00%
Non-U.S. | Corporate and other debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations	66.00%	67.00%
Non-U.S. | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocations	18.00%	19.00%

X

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

X

- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanDebtSecurityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gm_OtherInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=us-gaap_ForeignPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: