Commitments And Contingencies (Narrative) (Details)	12 Months Ended
Sep. 28, 2012
Commitments and Contingencies Disclosure [Abstract]
Term of agreement	20 years

Unrecorded Unconditional Obligation, Term of Agreement

No definition available.

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Namespace Prefix:	dlb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration