Basis Of Presentation (Policy)	12 Months Ended
Sep. 30, 2011
Basis Of Presentation [Abstract]
Principles Of Consolidation	*Principles of Consolidation* The consolidated financial statements include the accounts of Dolby Laboratories and our wholly-owned subsidiaries. In addition, we have consolidated the financial results of jointly-owned affiliated companies in which our principal stockholder has a controlling interest. We report these controlling interests as a separate line in our consolidated statements of operations as net (income) / loss attributable to controlling interest and in our consolidated balance sheets as controlling interest. We eliminate all intercompany accounts and transactions upon consolidation.
Use Of Estimates	*Use of Estimates* The preparation of the consolidated financial statements in accordance with accounting principles generally accepted in the U.S. ("GAAP") requires management to make certain estimates and assumptions that affect the amounts reported and disclosed in our consolidated financial statements and accompanying notes. Significant items subject to such estimates and assumptions include estimated selling prices for elements sold in multiple-element revenue arrangements, valuation allowances for accounts receivable, carrying values of inventories, products provided under operating leases, goodwill, intangible assets, stock-based compensation, fair values of investments, accrued expenses, including liabilities for unrecognized tax benefits, and deferred income tax assets. Actual results could differ from our estimates.
Fiscal Year	*Fiscal Year* Our fiscal year is a 52 or 53 week period ending on the last Friday in September. The fiscal years presented herein include 52 week periods ended September 25, 2009 (fiscal 2009), September 24, 2010 (fiscal 2010) and the 53 week period ended September 30, 2011 (fiscal 2011).
Reclassifications	*Reclassifications* We have reclassified certain prior period amounts within our consolidated statements of cash flows to conform to our current period presentation. In addition, we have reclassified our U.S. agency securities and U.S. government bonds as Level 1 securities to conform to our current period presentation. In the prior year, U.S. agency securities and U.S. government bonds were classified as Level 2 securities.

Basis Of Presentation (Policy)

12 Months Ended

Sep. 30, 2011

Principles of Consolidation

The consolidated financial statements include the accounts of Dolby Laboratories and our wholly-owned subsidiaries. In addition, we have consolidated the financial results of jointly-owned affiliated companies in which our principal stockholder has a controlling interest. We report these controlling interests as a separate line in our consolidated statements of operations as net (income) / loss attributable to controlling interest and in our consolidated balance sheets as controlling interest. We eliminate all intercompany accounts and transactions upon consolidation.

Use Of Estimates

Use of Estimates

The preparation of the consolidated financial statements in accordance with accounting principles generally accepted in the U.S. ("GAAP") requires management to make certain estimates and assumptions that affect the amounts reported and disclosed in our consolidated financial statements and accompanying notes. Significant items subject to such estimates and assumptions include estimated selling prices for elements sold in multiple-element revenue arrangements, valuation allowances for accounts receivable, carrying values of inventories, products provided under operating leases, goodwill, intangible assets, stock-based compensation, fair values of investments, accrued expenses, including liabilities for unrecognized tax benefits, and deferred income tax assets. Actual results could differ from our estimates.

Fiscal Year

Fiscal Year

Our fiscal year is a 52 or 53 week period ending on the last Friday in September. The fiscal years presented herein include 52 week periods ended September 25, 2009 (fiscal 2009), September 24, 2010 (fiscal 2010) and the 53 week period ended September 30, 2011 (fiscal 2011).

Reclassifications

Reclassifications

We have reclassified certain prior period amounts within our consolidated statements of cash flows to conform to our current period presentation.

In addition, we have reclassified our U.S. agency securities and U.S. government bonds as Level 1 securities to conform to our current period presentation. In the prior year, U.S. agency securities and U.S. government bonds were classified as Level 2 securities.

- Definition

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Research Bulletin (ARB)

-Number 51

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+ Details

- Definition

Disclosure of accounting policy for determining an entity's fiscal year or other fiscal period. This disclosure may include identification of the fiscal period end-date, the length of the fiscal period, any reporting period lag between the entity and its subsidiaries, or equity investees. If a reporting lag exists, the closing date of the entity having a different period end is generally noted, along with an explanation of the necessity for using different closing dates. Any intervening events that materially affect the entity's financial position or results of operations are generally also disclosed.

+ References+ Details