v2.3.0.15

Fair Value Measurements (Schedule Of Financial Assets Carried At Fair Value) (Details) (USD $) | Sep. 30, 2011 | Sep. 24, 2010
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | $ 823,007,000 |  | $ 884,727,000 |
Notional amount of derivative | 4,700,000 |  |  |
Commercial Paper [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  | 29,983,000 | [1]
Commercial Paper [Member] | Level 2 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  | 29,983,000 | [1]
Commercial Paper [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [1]
Corporate Bonds [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 176,958,000 | [2] | 29,658,000 | [1]
Corporate Bonds [Member] | Level 2 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 176,958,000 | [2] | 29,658,000 | [1]
Corporate Bonds [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [1]
Municipal Debt Securities [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 472,201,000 | [2] | 320,581,000 | [1]
Municipal Debt Securities [Member] | Level 2 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 472,201,000 | [2] | 320,581,000 | [1]
Municipal Debt Securities [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [1]
U.S. Agency Securities [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 29,919,000 | [2],[3] | 107,898,000 | [1]
U.S. Agency Securities [Member] | Level 1 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 29,919,000 | [2],[3] | 107,898,000 | [1]
U.S. Agency Securities [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [1]
U.S. Government Bonds [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  | 39,979,000 | [1]
U.S. Government Bonds [Member] | Level 1 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  | 39,979,000 | [1]
U.S. Government Bonds [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [1]
Investments Held In Supplemental Retirement Plan [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 1,891,000 | [4] | 2,200,000 | [4]
Investments Held In Supplemental Retirement Plan [Member] | Level 1 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 1,891,000 | [4] | 2,200,000 | [4]
Investments Held In Supplemental Retirement Plan [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [4]
Money Market Funds [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 142,038,000 | [3] | 354,428,000 | [1]
Money Market Funds [Member] | Level 1 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 142,038,000 | [3] | 354,428,000 | [1]
Money Market Funds [Member] | Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  | [1]
Level 1 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 173,848,000 |  | 504,505,000 |
Level 2 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value | 649,159,000 |  | 380,222,000 |
Level 3 [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Financial assets carried at fair value |  |  |  |
[1] | These assets are included within cash and cash equivalents, short term investments, and long term investments
[2] | These assets are included within short-term investments and long-term investments
[3] | These assets are included within cash and cash equivalents
[4] | These assets are included within prepaid expenses and other current assets and other non-current assets

X
- Definition Monetary amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 + Details
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X
- Definition This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + Details
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Balance Type: | debit
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X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + Details
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