| Document And Entity Information - USD ($) | 12 Months Ended | ||
| Sep. 28, 2018 | Oct. 26, 2018 | Mar. 31, 2017 | |
| Entity Registrant Name | Dolby Laboratories, Inc. | ||
| Entity Central Index Key | 0001308547 | ||
| Current Fiscal Year End Date | --09-28 | ||
| Entity Filer Category | Large Accelerated Filer | ||
| Document Type | 10-K/A | ||
| Document Period End Date | Sep. 28, 2018 | ||
| Document Fiscal Year Focus | 2018 | ||
| Document Fiscal Period Focus | FY | ||
| Amendment Flag | false | ||
| Entity Well-known Seasoned Issuer | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Public Float | $ 1,684,632,316 | ||
| Class A Common Stock [Member] | |||
| Entity Common Stock, Shares Outstanding | 64,002,056 | ||
| Class B Common Stock [Member] | |||
| Entity Common Stock, Shares Outstanding | 39,261,035 |
| Consolidated Balance Sheets (Parenthetical) | Oct. 26, 2018$ / shares |
| Class A Common Stock [Member] | |
| Common stock, par value (usd per share) | $ 0.001 |
| Class B Common Stock [Member] | |
| Common stock, par value (usd per share) | $ 0.001 |
