v2.3.0.15

Geographic Data (Schedule Of Concentration Of Revenue From Individual Geographic Regions) (Details) | 12 Months Ended
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Sep. 30, 2011 | Sep. 24, 2010 | Sep. 25, 2009
U.S. [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 32.00% | 34.00% | 35.00%
Japan [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 20.00% | 19.00% | 21.00%
Europe [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 15.00% | 16.00% | 17.00%
Taiwan [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 8.00% | 9.00% | 11.00%
South Korea [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 13.00% | 12.00% | 8.00%
China [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 6.00% | 5.00% | 6.00%
Other [Member] |  |  |
Revenue From External Customer [Line Items] |  |  |
Concentration of revenue from individual geographic regions | 6.00% | 5.00% | 2.00%

X
- Definition Concentration Of Revenue From Individual Geographic Regions + Details
Name: | dlb_ConcentrationOfRevenueFromIndividualGeographicRegions
Namespace Prefix: | dlb
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + Details
Name: | us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems
Namespace Prefix: | us-gaap
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration