| Cover | Oct. 30, 2019 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Amendment Description | Amendment No. 1 |
| Document Period End Date | Oct. 30, 2019 |
| Current Fiscal Year End Date | --12-28 |
| Entity File Number | 0-31983 |
| Entity Registrant Name | GARMIN LTD. |
| Entity Central Index Key | 0001121788 |
| Entity Tax Identification Number | 98-0229227 |
| Entity Incorporation, State or Country Code | V8 |
| Entity Address, Address Line One | Mühlentalstrasse 2 |
| Entity Address, City or Town | 8200 Schaffhausen |
| Entity Address, Country | CH |
| Entity Address, Postal Zip Code | N/A |
| City Area Code | +41 52 |
| Local Phone Number | 630 1600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Registered Shares |
| Trading Symbol | GRMN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
