| Document and Entity Information | Apr. 16, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 16, 2021 |
| Entity Registrant Name | Amgen Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-37702 |
| Entity Tax Identification Number | 95-3540776 |
| Entity Address, Address Line One | One Amgen Center Drive |
| Entity Address, City or Town | Thousand Oaks |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 91320-1799 |
| City Area Code | 805 |
| Local Phone Number | 447-1000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000318154 |
| Amendment Flag | false |
| Common Stock [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock $0.0001 par value |
| Trading Symbol | AMGN |
| Security Exchange Name | NASDAQ |
| 1.250% Senior Notes Due 2022 [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 1.250% Senior Notes Due 2022 |
| Trading Symbol | AMGN22 |
| Security Exchange Name | NASDAQ |
| 2.00% Senior Notes Due 2026 [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 2.000% Senior Notes Due 2026 |
| Trading Symbol | AMGN26 |
| Security Exchange Name | NASDAQ |
