| Cover Cover | Apr. 30, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 30, 2020 |
| Entity Registrant Name | GILEAD SCIENCES, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 0-19731 |
| Entity Tax Identification Number | 94-3047598 |
| Entity Address, Address Line One | 333 Lakeside Drive |
| Entity Address, City or Town | Foster City |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94404 |
| City Area Code | 650 |
| Local Phone Number | 574-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value, $0.001 per share |
| Trading Symbol | GILD |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000882095 |
| Amendment Flag | false |
