XML 66 R55.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Acquisition, Collaborations and Other Arrangements - Collaborations and Other Arrangements (Details) $ in Millions | 9 Months Ended
--- | ---
Sep. 30, 2018 USD ($)
Acquisition, Collaborations And Other Arrangements [Abstract] |
Initial consideration transferred | $ 333
Up-front collaboration expenses | $ 160

X
- Definition Acquisition, Collaborations And Other Arrangements [Abstract] + References No definition available. + Details
Name: | gild_AcquisitionCollaborationsAndOtherArrangementsAbstract
Namespace Prefix: | gild_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenue Collaboration Agreement, Initial Consideration Transferred + References No definition available. + Details
Name: | gild_RevenueCollaborationAgreementInitialConsiderationTransferred
Namespace Prefix: | gild_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of other research and development expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 730 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373 + Details
Name: | us-gaap_OtherResearchAndDevelopmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration