Composition Of Certain Financial Statement Captions (Schedule Of Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 29, 2024	Sep. 29, 2023
Composition Of Certain Financial Statement Captions [Abstract]
Amounts payable to patent administration program partners	$ 207,317	$ 150,509
Accrued compensation and benefits	80,295	118,728
Accrued professional fees	11,592	18,632
Unpaid property, plant, and equipment additions	21,576	18,002
Accrued customer refunds	2,578	3,878
Accrued market development funds	6,416	5,010
Other accrued liabilities	33,109	36,640
Total accrued liabilities	$ 362,883	$ 351,399

Accrual for Unpaid, Property, Plant and Equipment Additions

No definition available.

Name:	dlb_AccrualforUnpaidPropertyPlantandEquipmentAdditions
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Accrued Market Development Funds

+ References

No definition available.

+ Details

Name:	dlb_AccruedMarketDevelopmentFunds
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amounts Payable To Joint Licensing Program Partners

+ References

No definition available.

+ Details

Name:	dlb_AmountsPayableToJointLicensingProgramPartners
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Composition Of Certain Financial Statement Captions [Abstract]

+ References

No definition available.

+ Details

Name:	dlb_CompositionOfCertainFinancialStatementCaptionsAbstract
Namespace Prefix:	dlb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations, excluding pension and other postretirement benefits, incurred through that date and payable for perquisites provided to employees pertaining to services received from them. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_AccruedEmployeeBenefitsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

+ Details

Name:	us-gaap_AccruedLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

+ Details

Name:	us-gaap_AccruedProfessionalFeesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479777/606-10-55-27

+ Details

Name:	us-gaap_ContractWithCustomerRefundLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_OtherAccruedLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant