Composition Of Certain Financial Statement Captions (Schedule Of Accounts Receivable) (Details) - USD ($) $ in Thousands	Apr. 01, 2022	Sep. 24, 2021
Composition Of Certain Financial Statement Captions [Abstract]
Trade accounts receivable	$ 152,300	$ 160,112
Accounts receivable related to patent administration program	85,119	81,241
Contract assets	258,971	182,524
Accounts receivable, gross	496,390	423,877
Less: allowance for doubtful accounts	(10,281)	(8,952)
Accounts receivable, net	486,109	414,925
Unbilled Receivables, Current	$ 104,200	$ 97,500

Accounts Receivable And Contract With Customer, Asset, After Allowance For Credit Loss, Current

No definition available.

Name:	dlb_AccountsReceivableAndContractWithCustomerAssetAfterAllowanceForCreditLossCurrent
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Accounts Receivable And Contract With Customer, Asset, Allowance For Credit Loss, Current

+ References

No definition available.

+ Details

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

- Definition

Accounts Receivable Related To Patent Administration Program

+ References

No definition available.

+ Details

Name:	dlb_AccountsReceivableRelatedToPatentAdministrationProgram
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Trade Accounts Receivable

+ References

No definition available.

+ Details

Name:	dlb_TradeAccountsReceivable
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4531-111522

+ Details

Name:	us-gaap_AccountsReceivableGrossCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before allowance for credit loss, of right to consideration in exchange for good or service transferred to customer, when right is conditioned on something other than passage of time.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130533-203044

+ Details

Name:	us-gaap_ContractWithCustomerAssetGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

Name:	us-gaap_UnbilledReceivablesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant