XML 169 R65.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Accounting Policies - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Summary Of Accounting Policies [Line Items] |  |  |
Minimum recognizable tax benefit | 50.00% |  |
Sustainability threshold for uncertain tax position | 50.00% |  |
Cumulative probability threshold for realization of income tax benefits | 50.00% |  |
Employees average service period to grant awards | 3 years |  |
Advertising expenses | $ 17,000,000 | $ 15,000,000 | $ 14,000,000
Capitalized lease arrangement | $ 206,000,000 |  |
French [Member] | Research tax credits [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Tax credit carryforward expiration term | 3 years |  |
Minimum [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Equity investments, Ownership percentage | 20.00% |  |
Revenue recognition expected payment terms | 30 days |  |
Maximum [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Equity investments, Ownership percentage | 50.00% |  |
Revenue recognition expected payment terms | 90 days |  |
Maximum [Member] | Property Plant And Equipment [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Short term lease payments excluding capitalization amount | $ 5,000 |  |
Trademarks and Licenses [Member] | Minimum [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Estimated useful lives of intangible assets | 3 years |  |
Trademarks and Licenses [Member] | Maximum [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Estimated useful lives of intangible assets | 7 years |  |
Purchased and Internally Developed Software [Member] | Maximum [Member] |  |  |
Summary Of Accounting Policies [Line Items] |  |  |
Estimated useful lives of intangible assets | 4 years |  |

X
- Definition Cumulative probability threshold for realization of income tax benefits. + References No definition available. + Details
Name: | stm_CumulativeProbabilityThresholdForRealizationOfIncomeTaxBenefits
Namespace Prefix: | stm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum recognizable tax benefit. + References No definition available. + Details
Name: | stm_MinimumRecognizableTaxBenefit
Namespace Prefix: | stm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenue recognition expected payment terms. + References No definition available. + Details
Name: | stm_RevenueRecognitionExpectedPaymentTerms
Namespace Prefix: | stm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Short term lease payments excluding capitalization amount. + References No definition available. + Details
Name: | stm_ShortTermLeasePaymentsExcludingCapitalizationAmount
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Summary Of Accounting Policies [Line Items] + References No definition available. + Details
Name: | stm_SummaryOfAccountingPoliciesLineItems
Namespace Prefix: | stm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sustainability threshold for uncertain tax position. + References No definition available. + Details
Name: | stm_SustainabilityThresholdForUncertainTaxPosition
Namespace Prefix: | stm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax credit carryforward expiration term. + References No definition available. + Details
Name: | stm_TaxCreditCarryforwardExpirationTerm
Namespace Prefix: | stm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 720 -SubTopic 35 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848 + Details
Name: | us-gaap_AdvertisingExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_FinanceLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeTaxAuthorityNameAxis=us-gaap_MinistryOfTheEconomyFinanceAndIndustryFranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxCreditCarryforwardAxis=us-gaap_ResearchMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_PropertyPlantAndEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=stm_TrademarkAndLicenseFeeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_ComputerSoftwareIntangibleAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |