XML 125 R87.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Long-Term Debt - Additional Information (Detail) $ / shares in Units, € in Millions |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 11, 2017 USD ($) | Oct. 02, 2017 USD ($) shares | Jul. 03, 2017 USD ($) $ / shares shares | Oct. 03, 2016 USD ($) shares | Jul. 03, 2014 USD ($) $ / shares | Oct. 10, 2017 USD ($) shares | Jun. 30, 2017 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Jul. 03, 2014 USD ($) $ / shares | Dec. 31, 2017 EUR (€) | Aug. 31, 2017 EUR (€) | Mar. 12, 2013 USD ($) | Mar. 12, 2013 EUR (€)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from issuance of senior unsecured convertible bonds |  |  |  |  |  |  |  | $ 1,502,000,000 |  |  |  |  |  |  |
Conversion price adjusted |  | 1.16% |  | 1.24% |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued | shares |  |  |  |  |  |  |  | 4,300,000 |  |  |  |  |  |  |
Debt conversion, bond par value |  |  |  |  |  | $ 400,000,000 |  |  |  |  |  |  |  |  |
Conversion features of the instruments value |  |  | $ 242,000,000 |  |  |  |  | $ 242,000,000 | $ 121,000,000 | $ 0 |  |  |  |  |
Allocated debt issuance costs |  |  | 1,000,000 |  | $ 1,000,000 | 340,000,000 |  | 95,000,000 |  |  |  |  |  |  |
Unamortized debt discount and issuance costs totalled |  |  |  |  |  |  |  | 221,000,000 | $ 74,000,000 |  |  |  |  |  |
Debt Conversion,Cash redemption | $ 60,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on financial instruments, net |  |  |  |  |  |  |  | (16,000,000) |  |  |  |  |  |  |
Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from issuance of senior unsecured convertible bonds |  |  | 1,502,000,000 |  | 994,000,000 |  |  |  |  |  |  |  |  |  |
Medium Term Credit Facilities [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unutilized committed medium term credit facilities |  |  |  |  |  |  |  | 580,000,000 |  |  |  |  |  |  |
Multi Currency Loan to Support our Industrial and R&D Programs [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit outstanding amount | € |  |  |  |  |  |  |  |  |  |  |  |  |  |  | € 350
Amount outstanding |  |  |  |  |  |  |  | 235,000,000 |  |  |  |  |  |  |
Line of credit amount withdrawn |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 471,000,000 |
Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of liability component |  |  | $ 1,266,000,000 |  | $ 878,000,000 |  |  |  |  |  | $ 878,000,000 |  |  |  |
Europe [Member] | Multi Currency Loan to Support our Industrial and R&D Programs [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit outstanding amount | € |  |  |  |  |  |  |  |  |  |  |  | € 350 |  |  |
Amount outstanding |  |  |  |  |  |  |  | 166,000,000 |  |  |  |  |  |  |
Line of credit amount withdrawn |  |  |  |  |  |  |  | $ 321,000,000 |  |  |  | € 100 |  |  |
Zero Coupon due 2019 (Tranche A) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  | 1.00% |  |  |  |  |  | 1.00% |  |  |  |
Senior unsecured convertible bonds conversion premium rate |  |  |  |  | 30.00% |  |  |  |  |  | 30.00% |  |  |  |
Debt conversion, bond par value |  |  |  |  |  |  | $ 600,000,000 |  |  |  |  |  |  |  |
Debt discount rate |  |  |  |  |  |  | 2.09% | 2.09% |  | 2.40% | 2.40% |  |  |  |
Conversion features of the instruments value |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |  |
Allocated debt issuance costs |  |  |  |  |  |  | 598,000,000 |  |  |  |  |  |  |  |
Debt Conversion,Cash redemption |  |  |  |  |  |  | $ 2,000,000 |  |  |  |  |  |  |  |
Zero Coupon due 2019 (Tranche A) [Member] | Treasury Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued | shares |  |  |  |  |  |  | 13,000,000 |  |  |  |  |  |  |  |
Zero Coupon due 2019 (Tranche A) [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument principal amount |  |  |  |  | $ 600,000,000 |  |  |  |  |  | $ 600,000,000 |  |  |  |
Long-term debt maturity date |  |  |  |  |  |  |  | 2019 |  |  |  |  |  |  |
Interest rate |  |  |  |  | 0.00% |  |  | 0.00% |  |  | 0.00% | 0.00% |  |  |
Percentage at which bonds issued |  |  | 101.265% |  |  |  |  |  |  |  |  |  |  |  |
Zero Coupon due 2019 (Tranche A) [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of liability component |  |  |  |  |  |  | $ 574,000,000 | $ 574,000,000 |  |  |  |  |  |  |
Loss on financial instruments, net |  |  |  |  |  |  | $ 5,000,000 | $ 5,000,000 |  |  |  |  |  |  |
1.0% due 2021 (Tranche B) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument periodic payment |  |  |  |  |  |  |  | Semi-annually |  |  |  |  |  |  |
Interest rate |  |  |  |  | 1.00% |  |  |  |  |  | 1.00% |  |  |  |
Senior unsecured convertible bonds conversion premium rate |  |  |  |  | 31.00% |  |  |  |  |  | 31.00% |  |  |  |
Debt conversion, bond par value |  |  |  |  |  | $ 60,000,000 |  |  |  |  |  |  |  |  |
Debt discount rate |  |  |  |  |  | 2.47% |  | 2.47% |  | 3.22% | 3.22% |  |  |  |
Conversion features of the instruments value |  |  |  |  |  | $ 0 |  |  |  |  |  |  |  |  |
Allocated debt issuance costs |  |  |  |  |  | 59,000,000 |  |  |  |  |  |  |  |  |
Debt Conversion,Cash redemption |  |  |  |  |  | $ 1,000,000 |  |  |  |  |  |  |  |  |
1.0% due 2021 (Tranche B) [Member] | Treasury Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued | shares |  |  |  |  |  | 13,700,000 |  |  |  |  |  |  |  |  |
1.0% due 2021 (Tranche B) [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument principal amount |  |  |  |  | $ 400,000,000 |  |  |  |  |  | $ 400,000,000 |  |  |  |
Long-term debt maturity date |  |  |  |  |  |  |  | 2021 |  |  |  |  |  |  |
Interest rate |  |  |  |  | 1.00% |  |  | 1.00% |  |  | 1.00% | 1.00% |  |  |
1.0% due 2021 (Tranche B) [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of liability component |  |  |  |  |  | $ 370,000,000 |  | $ 370,000,000 |  |  |  |  |  |  |
Loss on financial instruments, net |  |  |  |  |  | $ 11,000,000 |  | $ 11,000,000 |  |  |  |  |  |  |
Zero-coupon, due 2022 (Tranche A) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt discount rate |  |  |  |  |  |  |  | 2.70% | 2.70% |  |  |  |  |  |
Zero-coupon, due 2022 (Tranche A) [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt maturity date |  |  |  |  |  |  |  | 2022 |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  |  | 0.00% |  |  |  | 0.00% |  |  |
0.25%, due 2024 (Tranche B) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  |  | 0.25% |  |  |  | 0.25% |  |  |
Debt discount rate |  |  |  |  |  |  |  | 3.28% | 3.28% |  |  |  |  |  |
0.25%, due 2024 (Tranche B) [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt maturity date |  |  |  |  |  |  |  | 2024 |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  |  | 0.25% |  |  |  | 0.25% |  |  |
Dual Tranche Senior Unsecured Convertible Bonds [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument principal amount |  |  | $ 1,500,000,000 |  | $ 1,000,000,000 |  |  |  |  |  | $ 1,000,000,000 |  |  |  |
Senior unsecured convertible bonds conversion price | $ / shares |  |  | $ 20.54 |  | $ 12 |  |  |  |  |  | $ 12 |  |  |  |
Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued | shares |  | 16,178 | 9,737 | 16,491 |  |  |  |  |  |  |  |  |  |  |
Debt conversion, bond par value |  | $ 200,000 | $ 200,000 | $ 200,000 |  |  |  |  |  |  |  |  |  |  |
Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from issuance of senior unsecured convertible bonds |  | $ 994 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued | shares |  |  | 9,737 | 16,366 |  |  |  |  |  |  |  |  |  |  |
Zero Coupon Due 2022 (Tranche A) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior unsecured convertible bonds conversion premium rate |  |  | 37.50% |  |  |  |  |  |  |  |  |  |  |  |
Zero Coupon Due 2022 (Tranche A) [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument principal amount |  |  | $ 750,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt maturity date |  |  |  |  |  |  |  | 2022 |  |  |  |  |  |  |
0.25% due 2022(Tranche B) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument periodic payment |  |  |  |  |  |  |  | Semi-annually |  |  |  |  |  |  |
Senior unsecured convertible bonds conversion premium rate |  |  | 37.50% |  |  |  |  |  |  |  |  |  |  |  |
0.25% due 2022(Tranche B) [Member] | Senior Unsecured Convertible Bonds [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument principal amount |  |  | $ 750,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt maturity date |  |  |  |  |  |  |  | 2024 |  |  |  |  |  |  |
Interest rate |  |  | 0.25% |  |  |  |  |  |  |  |  |  |  |  |
New Medium Term Credit Facility [Member] | Europe [Member] | Multi Currency Loan to Support our Industrial and R&D Programs [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit outstanding amount | € |  |  |  |  |  |  |  |  |  |  |  |  | € 500 |  |
Line of credit amount withdrawn |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |

X
- Definition Credit Facility Amount Outstanding + References No definition available. + Details
Name: | stm_CreditFacilityAmountOutstanding
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Debt instrument convertible conversion premium percentage. + References No definition available. + Details
Name: | stm_DebtInstrumentConvertibleConversionPremiumPercentage
Namespace Prefix: | stm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument Maturity Year + References No definition available. + Details
Name: | stm_DebtInstrumentMaturityYear
Namespace Prefix: | stm_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain or loss of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain or loss which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains or losses realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments of the subject investments. Finally, this item would also include aggregate net gain and losses (whether realized or unrealized) on all derivative instruments held for trading purposes whether or not settled physically. + References No definition available. + Details
Name: | stm_GainLossOnFinancialInstrumentsNet
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line Of Credit Facility Amount Drawn + References No definition available. + Details
Name: | stm_LineOfCreditFacilityAmountDrawn
Namespace Prefix: | stm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage at issuance for Zero coupon bonds + References No definition available. + Details
Name: | stm_PercentageAtIssuanceForZeroCouponBonds
Namespace Prefix: | stm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 25 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=51819886&loc=SL6014347-161799 + Details
Name: | us-gaap_AdjustmentsToAdditionalPaidInCapitalEquityComponentOfConvertibleDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 + Details
Name: | us-gaap_DebtConversionConvertedInstrumentAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Dividend or interest rate associated with the financial instrument issued in exchange for the original debt being converted in a noncash or part noncash transaction. Noncash are transactions that affect recognized assets or liabilities but that do not result in cash receipts or cash payments. Part noncash refers to that portion of the transaction not resulting in cash receipts or cash payments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 + Details
Name: | us-gaap_DebtConversionConvertedInstrumentRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 + Details
Name: | us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 + Details
Name: | us-gaap_DebtConversionOriginalDebtAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The price per share of the conversion feature embedded in the debt instrument. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Description of the frequency of periodic payments (monthly, quarterly, annual). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentFrequencyOfPeriodicPayment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unamortized debt discount (premium) and debt issuance costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399 + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueInputsDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
Name: | us-gaap_LongTermDebtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfUnsecuredDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash outflow from the repayment of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585 + Details
Name: | us-gaap_RepaymentsOfConvertibleDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=stm_SeniorUnsecuredConvertibleBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=stm_MediumTermCreditFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=stm_UncommittedShortTermCreditFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_StatementGeographicalAxis=us-gaap_EuropeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_ZeroCouponDueTwoThousandNineteenTrancheAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_TreasuryStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_OnePointZeroPercentageDueTwoThousandTwentyOneTrancheBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_ZeroCouponDueTwoThousandAndTwentyTwoTrancheaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_ZeroPointTwoFivePercentageDueTwoThousandAndTwentyFourTranchebMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_DualTrancheSeniorUnsecuredConvertibleBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_TrancheOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_TrancheTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_ZeroCouponDueTwoThousandTwentyTwoTrancheAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_ZeroPointTwoFivePercentageDueTwoThousandTwentyTwoTrancheBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=stm_NewCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |