Commitments - Company's Commitments (Detail) $ in Millions	Dec. 31, 2021 USD ($)
Recorded Unconditional Purchase Obligation [Line Items]
Purchase obligations, Total	$ 4,064
Purchase obligations, 2022	3,272
Purchase obligations, 2023	405
Purchase obligations, 2024	186
Purchase obligations, 2025	163
Purchase obligations, 2026	38
Other obligations, Total	1,059
Other obligations, 2022	621
Other obligations, 2023	172
Other obligations, 2024	107
Other obligations, 2025	63
Other obligations, 2026	30
Other obligations, Thereafter	66
Company's commitments, Total	5,123
Company's commitments, 2022	3,893
Company's commitments, 2023	577
Company's commitments, 2024	293
Company's commitments, 2025	226
Company's commitments, 2026	68
Company's commitments, Thereafter	66
Equipment Purchase [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Purchase obligations, Total	2,412
Purchase obligations, 2022	2,406
Purchase obligations, 2023	6
Foundry Purchase [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Purchase obligations, Total	1,488
Purchase obligations, 2022	768
Purchase obligations, 2023	358
Purchase obligations, 2024	167
Purchase obligations, 2025	157
Purchase obligations, 2026	38
Software, Design, Technologies and Licenses [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Purchase obligations, Total	164
Purchase obligations, 2022	98
Purchase obligations, 2023	41
Purchase obligations, 2024	19
Purchase obligations, 2025	$ 6

Obligation.

No definition available.

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Balance Type:	credit
Period Type:	instant

- Definition

Obligation Due Current.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Obligation Due In Five Years.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Obligation Due In Four Years.

+ References

No definition available.

+ Details

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Namespace Prefix:	stm_
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Period Type:	instant

- Definition

Obligation Due In Three Years.

+ References

No definition available.

+ Details

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- Definition

Obligation Due In Two Years.

+ References

No definition available.

+ Details

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- Definition

Obligation Due Thereafter.

+ References

No definition available.

+ Details

Name:	stm_ObligationDueThereafter
Namespace Prefix:	stm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

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

- Definition

Amount of commitment classified as other to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Amount of commitment classified as other to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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- Definition

Amount of commitment classified as other to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123406679&loc=d3e25383-109308

+ Details

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Period Type:	instant

- Definition

Amount of recorded unconditional purchase obligation to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of recorded unconditional purchase obligation to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of recorded unconditional purchase obligation to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Amount of recorded unconditional purchase obligation to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of recorded unconditional purchase obligation to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- 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

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