| Cover | Jan. 28, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jan. 28, 2021 |
| Current Fiscal Year End Date | --01-01 |
| Entity File Number | 000-29823 |
| Entity Registrant Name | SILICON LABORATORIES INC. |
| Entity Central Index Key | 0001038074 |
| Entity Tax Identification Number | 74-2793174 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 400 West Cesar Chavez |
| Entity Address, City or Town | Austin |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 78701 |
| City Area Code | 512 |
| Local Phone Number | 416-8500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value |
| Trading Symbol | SLAB |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
