v2.3.0.15

Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2011

Summary Of Significant Accounting Policies [Abstract]

Schedule Of Property, Plant, And Equipment, Estimated Useful Life

Systems and software		3to 5 years
Machinery and equipment		3to 8 years
Furniture and fixtures		5to 8 years
Leasehold improvements		Lesser of useful life or related lease term
Buildings		Up to 40 years

X

- Definition

Property Plant And Equipment Estimated Useful Life [Table Text Block]

+ Details

Name:	dlb_PropertyPlantAndEquipmentEstimatedUsefulLifeTableTextBlock
Namespace Prefix:	dlb
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_AccountingPoliciesAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration