Financial Instruments And Fair Value (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Apr. 24, 2009	Apr. 27, 2012	Apr. 29, 2011
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Estimated Fair Value		$ 4,825.2	$ 4,042.3
Cumulative net temporary impairment charges within accumulated other comprehensive income		4.9	3.4
Auction Rate Securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Auction rate securities, par value		55.6	71.3
Estimated Fair Value		51.0	65.1
Cumulative net temporary impairment charges within accumulated other comprehensive income		3.1
Cumulative other-than temporary impairments recognized in results of operations	$ 1.4

Accumulated appreciation or loss, net of tax, in value of the total of available-for-sale securities at the end of an accounting period.

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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.

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- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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