XML 121 R75.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2

Goodwill - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 121	$ 123
Business combination	43
Foreign currency translation	(2)	(2)
Goodwill, Ending Balance	162	121
Automotive and Discrete Group (ADG) [Member]
Goodwill [Line Items]
Business combination	43
Goodwill, Ending Balance	43
Microcontrollers and Digital ICs Group (MDG) [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	119	121
Foreign currency translation	(2)	(2)
Goodwill, Ending Balance	117	119
Analog, MEMS & Sensors Group (AMS) [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	2	2
Goodwill, Ending Balance	$ 2	$ 2

X

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

+ Details

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267

+ Details

Name:	us-gaap_GoodwillAcquiredDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_GoodwillLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e961-128460

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267

+ Details

Name:	us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=stm_AutomotiveAndDiscreteGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=stm_MicrocontrollersAndDigitalIcsGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=stm_AnalogAndMEMSAndSensorsGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: