Fair Value Hierarchy of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	May 24, 2013	Feb. 22, 2013
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	$ 103.1	$ 150.4
Restricted Cash and Cash Equivalents	3.5	3.5
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	110.8	158.3
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] \| Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] \| US Government Agencies Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	4.2	4.4
Fair Value, Inputs, Level 1 [Member] \| Asset-backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] \| Municipal Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure		0
Fair Value, Inputs, Level 1 [Member] \| Other Debt Obligations [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] \| Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] \| Canadian Asset Backed Commercial Paper Restructuring Notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Restricted Cash and Cash Equivalents	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure	0.9	1.3
Assets, Fair Value Disclosure	40.4	97.4
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	(0.2)	(1.9)
Liabilities, Fair Value Disclosure	(0.2)	(1.9)
Fair Value, Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	15.4	30.3
Fair Value, Inputs, Level 2 [Member] \| US Government Agencies Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	19.3	44.1
Fair Value, Inputs, Level 2 [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] \| Asset-backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	4.0	5.5
Fair Value, Inputs, Level 2 [Member] \| Municipal Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure		14.1
Fair Value, Inputs, Level 2 [Member] \| Other Debt Obligations [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0.8	2.1
Fair Value, Inputs, Level 2 [Member] \| Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] \| Canadian Asset Backed Commercial Paper Restructuring Notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Restricted Cash and Cash Equivalents	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	13.7	13.3
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] \| Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] \| US Government Agencies Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] \| Asset-backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] \| Municipal Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure		0
Fair Value, Inputs, Level 3 [Member] \| Other Debt Obligations [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] \| Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	9.9	9.8
Fair Value, Inputs, Level 3 [Member] \| Canadian Asset Backed Commercial Paper Restructuring Notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	3.8	3.5
Estimate of Fair Value, Fair Value Disclosure [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	103.1	150.4
Restricted Cash and Cash Equivalents	3.5	3.5
Foreign Currency Contract, Asset, Fair Value Disclosure	0.9	1.3
Assets, Fair Value Disclosure	164.9	269.0
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	(0.2)	(1.9)
Liabilities, Fair Value Disclosure	(0.2)	(1.9)
Estimate of Fair Value, Fair Value Disclosure [Member] \| Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	19.3	44.1
Estimate of Fair Value, Fair Value Disclosure [Member] \| US Government Agencies Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	15.4	30.3
Estimate of Fair Value, Fair Value Disclosure [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	4.2	4.4
Estimate of Fair Value, Fair Value Disclosure [Member] \| Asset-backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	4.0	5.5
Estimate of Fair Value, Fair Value Disclosure [Member] \| Municipal Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure		14.1
Estimate of Fair Value, Fair Value Disclosure [Member] \| Other Debt Obligations [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0.8	2.1
Estimate of Fair Value, Fair Value Disclosure [Member] \| Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	9.9	9.8
Estimate of Fair Value, Fair Value Disclosure [Member] \| Canadian Asset Backed Commercial Paper Restructuring Notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 3.8	$ 3.5

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

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 includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

+ References+ Details

- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References+ Details