Securities (Summary Of Securities) (Details) (USD $) In Millions	Sep. 25, 2011	Dec. 26, 2010
Market Value	$ 31.7
Short-Term Investments [Member]
Amortized Cost	0.2	0.1
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Market Value	0.2	0.1
Short-Term Investments [Member] \| U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member]
Amortized Cost	0.2	0.1
Market Value	0.2	0.1
Auction Rate Securities [Member] \| Long-Term Investments [Member]
Amortized Cost	35.7	35.3
Gross Unrealized Losses	(6.7)	(7.3)
Market Value	29.0	28.0
Long-Term Investments [Member]
Amortized Cost	37.8	37.5
Gross Unrealized Gains	0.4	0.1
Gross Unrealized Losses	(6.7)	(7.3)
Market Value	31.5	30.3
Long-Term Investments [Member] \| U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member]
Amortized Cost	1.8	1.9
Gross Unrealized Gains	0.4	0.1
Market Value	2.2	2.0
Long-Term Investments [Member] \| Corporate Debt Securities [Member]
Amortized Cost	0.3	0.3
Market Value	$ 0.3	$ 0.3

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References+ Details