Long-Term Debt - Long-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Long-term debt
Finance leases:	$ 66
Total	2,953	$ 2,927
Less current portion	(990)	(217)
Total long-term debt, less current portion	1,963	2,710
3.62% due 2028, floating interest rate at Euribor +0.589%
Loans Payable [Abstract]
Bank loans (including current portion)	$ 106	141
Long-term debt
Interest rate	3.62%
Basis spread on floating rate	0.589%
4.19% due 2029, floating interest rate at Euribor +0.564%
Loans Payable [Abstract]
Bank loans (including current portion)	$ 127	162
Long-term debt
Interest rate	4.19%
Basis spread on floating rate	0.564%
3.96% due 2031, floating interest rate at Euribor +0.473%
Loans Payable [Abstract]
Bank loans (including current portion)	$ 244	296
Long-term debt
Interest rate	3.96%
Basis spread on floating rate	0.473%
4.23% due 2031, floating interest rate at Euribor +0.550%
Loans Payable [Abstract]
Bank loans (including current portion)	$ 120	146
Long-term debt
Interest rate	4.23%
Basis spread on floating rate	0.55%
3.21% due 2033, floating interest rate at Euribor +0.558%
Loans Payable [Abstract]
Bank loans (including current portion)	$ 281	332
Long-term debt
Interest rate	3.21%
Basis spread on floating rate	0.558%
6.19% due 2034, floating interest rate at Secured Overnight Financing Rate +0.939%
Loans Payable [Abstract]
Bank loans (including current portion)	$ 300	0
Long-term debt
Interest rate	6.19%
Basis spread on floating rate	0.939%
3.34% due 2027, floating interest rate at Euribor +0.690%
Long-term debt
Interest rate	3.34%
Basis spread on floating rate	0.69%
3.34% due 2027, floating interest rate at Euribor +0.690% \| Credit Facility from Cassa Depositi e Prestiti SpA ("CDP SpA")
Loans Payable [Abstract]
Bank loans (including current portion)	$ 65	97
3.91% due 2028, floating interest rate at Euribor +0.550%
Long-term debt
Interest rate	3.91%
Basis spread on floating rate	0.55%
3.91% due 2028, floating interest rate at Euribor +0.550% \| Credit Facility from Cassa Depositi e Prestiti SpA ("CDP SpA")
Loans Payable [Abstract]
Bank loans (including current portion)	$ 69	92
4.21% due 2029, floating interest rate at Euribor +0.850%
Long-term debt
Interest rate	4.21%
Basis spread on floating rate	0.85%
4.21% due 2029, floating interest rate at Euribor +0.850% \| Credit Facility from Cassa Depositi e Prestiti SpA ("CDP SpA")
Loans Payable [Abstract]
Bank loans (including current portion)	$ 74	95
zero-coupon, due 2025 ("Tranche A") \| Dual tranche senior unsecured convertible bonds
Long-term debt
Dual tranche senior unsecured convertible bonds	$ 749	748
Interest rate	0.00%
zero-coupon, due 2027 ("Tranche B") \| Dual tranche senior unsecured convertible bonds
Long-term debt
Dual tranche senior unsecured convertible bonds	$ 749	748
Interest rate	0.00%
3.58% due 2025, fixed interest rate
Long-term debt
Finance leases:	$ 8	0
Interest rate	3.58%
3.86% due 2027, fixed interest rate
Long-term debt
Finance leases:	$ 34	38
Interest rate	3.86%
3.78% due 2042, fixed interest rate
Long-term debt
Finance leases:	$ 23	25
Interest rate	3.78%
1.75% due 2042, fixed interest rate
Long-term debt
Finance leases:	$ 1	2
Interest rate	1.75%
0.26% (weighted average), due 2025-2028, fixed interest rate
Long-term debt
Other funding program loans	$ 3	$ 5
Interest rate	0.26%

No definition available.

Name:	us-gaap_DebtAndCapitalLeaseObligationsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

Name:	us-gaap_FinanceLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_LoansPayableAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of loans from a bank with maturities initially due after one year or beyond the normal operating cycle if longer.

+ References

+ Details

Name:	us-gaap_LoansPayableToBank
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-4

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as current. Excludes lease obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term loans payable classified as other.

+ References

+ Details

Name:	us-gaap_OtherLoansPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

+ Details

Name:	us-gaap_UnsecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FundingProgramLoansDueTwoThousandAndTwentyEightFloatingInterestRateAtEuriborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FundingProgramLoansDueTwoThousandAndTwentyNineFloatingInterestRateAtEuriborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FundingProgramLoansDueTwoThousandAndThirtyOneFloatingInterestRateAtEuriborOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FundingProgramLoansDueTwoThousandAndThirtyOneFloatingInterestRateAtEuriborTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FundingProgramLoansDueTwoThousandAndThirtyThreeFloatingInterestRateAtEuriborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FundingProgramLoansDueTwoThousandAndThirtyFourFloatingInterestRateAtSOFRMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_CreditFacilityDueTwoThousandAndTwentySevenFloatingInterestRateAtEuriborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=stm_CassaDepositiPrestitiSpACDPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_CreditFacilityDueTwoThousandAndTwentyEightFloatingInterestRateAtEuriborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_CreditFacilityDueTwoThousandAndTwentyNineFloatingInterestRateAtEuriborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_ZeroCouponDueTwoThousandAndTwentyFiveTrancheAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_ZeroCouponDueTwoThousandAndTwentySevenTrancheBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FinanceLeasesThreePointFiveEightPercentageDueTwoThousandTwentyFiveFixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FinanceLeasesThreePointEightSixPercentageDueTwoThousandTwentySevenFixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FinanceLeasesThreePointSevenEightPercentageDueTwoThousandFortyTwoFixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_FinanceLeasesOnePointSevenFivePercentageDueTwoThousandFortyTwoFixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=stm_ZeroPointTwoSixPercentageWeightedAverageDueTwoThousandAndTwentyFiveToTwoThousandAndTwentyEightFixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: