XML 148 R135.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Financial Risk Factors - Schedule of Assets (Liabilities) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - Fair Value, Inputs, Level 3 [Member] $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
Beginning balance | $ (12)
Contingent consideration on business combination | 12
Amount of total losses for the period included in earnings attributable to assets still held at the reporting date | $ 0

X
- Definition Fair value measurement with unobservable inputs reconciliation recurring basis asset still held gain loss included in earnings at reporting date. + References No definition available. + Details
Name: | stm_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetStillHeldGainLossIncludedInEarningsAtReportingDate
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value measurement with unobservable inputs reconciliations recurring basis business combination contingent consideration. + References No definition available. + Details
Name: | stm_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisBusinessCombinationContingentConsideration
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Definition Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |