XML 92 R78.htm IDEA: XBRL DOCUMENT
v3.20.4

Business Combinations - Schedule of Preliminary Fair Value of Identifiable Assets and Assumed Liabilities (Parenthetical) (Detail) $ in Millions | Dec. 31, 2020 USD ($)
--- | ---
Automotive and Discrete Group (ADG) and Microcontrollers And Digital Ics Group [Member] |
Business Acquisition [Line Items] |
Goodwill estimated tax deductible | $ 45

X
- Definition Goodwill estimated tax deductible. + References No definition available. + Details
Name: | stm_GoodwillEstimatedTaxDeductible
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=stm_AutomotiveAndDiscreteGroupADGAndMicrocontrollersAndDigitalIcsGroupMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |