XML 137 R124.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Income Tax - Gross Deferred Tax Assets on Tax Loss Carryforwards and Investment Credits Expiration (Detail) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Income Tax Disclosure [Abstract] |  |
2019 | $ 15 |
2020 | 15 |
2021 | 3 |
2022 | 6 |
2023 | 7 |
Thereafter | 557 |
Total | $ 603 | $ 740

X
- Definition Deferred tax assets on tax loss carryforwards and investment credits expiration Thereafter. + References No definition available. + Details
Name: | stm_DeferredTaxAssetsOnTaxLossCarryforwardsAndInvestmentCreditsExpirationThereafter
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferred Tax Assets On Tax Loss Carryforwards And Investment Credits Expiration Year Five + References No definition available. + Details
Name: | stm_DeferredTaxAssetsOnTaxLossCarryforwardsAndInvestmentCreditsExpirationYearFive
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferred tax assets on tax loss carryforwards and investment credits expiration Year Four. + References No definition available. + Details
Name: | stm_DeferredTaxAssetsOnTaxLossCarryforwardsAndInvestmentCreditsExpirationYearFour
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferred tax assets on tax loss carryforwards and investment credits expiration. + References No definition available. + Details
Name: | stm_DeferredTaxAssetsOnTaxLossCarryforwardsAndInvestmentCreditsExpirationYearOne
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferred tax assets on tax loss carryforwards and investment credits expiration Year Three. + References No definition available. + Details
Name: | stm_DeferredTaxAssetsOnTaxLossCarryforwardsAndInvestmentCreditsExpirationYearThree
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferred tax assets on tax loss carryforwards and investment credits expiration Year Two. + References No definition available. + Details
Name: | stm_DeferredTaxAssetsOnTaxLossCarryforwardsAndInvestmentCreditsExpirationYearTwo
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 20 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=115928272&loc=d3e28680-109314 + Details
Name: | us-gaap_DeferredTaxAssetsOperatingLossCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_IncomeTaxDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration