XML 117 R104.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Post-Employment and Other Long-Term Employees Benefits - Pension Plan Asset Allocation (Detail) | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Allocation of pension plan assets | 100.00% | 100.00%
Cash and Cash Equivalents [Member] |  |
Allocation of pension plan assets | 1.00% | 1.00%
Equity Securities [Member] |  |
Allocation of pension plan assets | 17.00% | 23.00%
Government Debt Securities [Member] |  |
Allocation of pension plan assets | 12.00% | 12.00%
Corporate Debt Securities [Member] |  |
Allocation of pension plan assets | 22.00% | 15.00%
Investment Funds [Member] |  |
Allocation of pension plan assets | 21.00% | 21.00%
Real Estate [Member] |  |
Allocation of pension plan assets | 1.00% | 2.00%
Other (Mainly Insurance Assets - Contracts and Reserves) [Member] |  |
Allocation of pension plan assets | 26.00% | 26.00%

X
- Definition Percentage of actual 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/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember
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_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=stm_InvestmentFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=stm_OtherPlanAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |