INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 31,894		$ 25,794
Accumulated Amortization	(11,265)		(10,121)
Foreign Currency Translation Adjustment	1		1
Net Carrying Amount	20,630		15,674
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	39,014		39,014
Accumulated Amortization	(11,265)		(10,121)
Foreign Currency Translation Adjustment	1		1
Net Carrying Amount	27,750		28,894
IPR&D
Indefinite-lived Intangible Assets (Excluding Goodwill) [Abstract]
Gross Carrying Amount	7,120		13,220
Foreign Currency Translation Adjustment	0		0
Net Carrying Amount	7,120		13,220
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Reclassified intangible assets		$ (6,100)
Intangible asset – sofosbuvir
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,720		10,720
Accumulated Amortization	(6,700)		(6,350)
Foreign Currency Translation Adjustment	0		0
Net Carrying Amount	4,020		4,370
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	(6,700)		(6,350)
Intangible asset – axicabtagene ciloleucel
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,110		7,110
Accumulated Amortization	(2,111)		(1,908)
Foreign Currency Translation Adjustment	0		0
Net Carrying Amount	4,999		5,202
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	(2,111)		(1,908)
Intangible asset – Trodelvy
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	11,730		5,630
Accumulated Amortization	(1,462)		(973)
Foreign Currency Translation Adjustment	0		0
Net Carrying Amount	10,268		4,657
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	(1,462)		(973)
Reclassified intangible assets		$ 6,100
Intangible asset – Hepcludex
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	845		845
Accumulated Amortization	(201)		(158)
Foreign Currency Translation Adjustment	0		0
Net Carrying Amount	644		687
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	(201)		(158)
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,489		1,489
Accumulated Amortization	(792)		(733)
Foreign Currency Translation Adjustment	1		1
Net Carrying Amount	698		758
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	$ (792)		$ (733)

Finite-Lived And Indefinite-Lived Intangible Assets, Foreign Currency Translation Gain (Loss), Cumulative Gain (Loss)

No definition available.

Name:	gild_FiniteLivedAndIndefiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLossCumulativeGainLoss
Namespace Prefix:	gild_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Finite Lived Intangible Assets, Foreign Currency Translation Gain (Loss), Cumulative Gain (Loss)

+ References

No definition available.

+ Details

Name:	gild_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLossCumulativeGainLoss
Namespace Prefix:	gild_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Finite-Lived Intangible Assets, Gross, Reclassified

+ References

No definition available.

+ Details

Name:	gild_FiniteLivedIntangibleAssetsGrossReclassified
Namespace Prefix:	gild_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indefinite-Lived Intangible Assets, Foreign Currency Translation Gain (Loss), Cumulative Gain (Loss)

+ References

No definition available.

+ Details

Name:	gild_IndefiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLossCumulativeGainLoss
Namespace Prefix:	gild_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total carrying amount of assets (excluding financial assets) that lack physical substance, excluding goodwill, having a projected indefinite period of benefit.

+ References

No definition available.

+ Details

Name:	gild_TotalIndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	gild_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ 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(16))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

+ Details

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

- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 928
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483147/928-340-50-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

+ Details

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

- 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

+ Details

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

- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483154/926-20-50-5

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

+ Details

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

- Definition

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount before accumulated amortization of intangible assets, excluding goodwill.

+ References

+ Details

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

- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph ((a)(1),(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482686/350-30-45-1

+ Details

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

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_InProcessResearchAndDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=gild_IntangibleAssetSofosbuvirMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=gild_AxicabtageneciloleucelDLBCLMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=gild_TrodelvyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=gild_HepcludexMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_OtherIntangibleAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: