| Cover | Mar. 02, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 2, 2020 |
| Current Fiscal Year End Date | --10-02 |
| Entity File Number | 1-7598 |
| Entity Registrant Name | VARIAN MEDICAL SYSTEMS, INC. |
| Entity Central Index Key | 0000203527 |
| Entity Tax Identification Number | 94-2359345 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 3100 Hansen Way |
| Entity Address, City or Town | Palo Alto |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94304-1030 |
| City Area Code | 650 |
| Local Phone Number | 493-4000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | VAR |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
