Financial Instruments and Fair Value (Narrative) (Details) (USD $) In Millions	12 Months Ended
	Apr. 29, 2011	Apr. 30, 2010	Apr. 24, 2009
Distributions from investment in primary fund	$ 2.5	$ 1.0
Auction rate securities	As of April 29, 2011 and April 30, 2010, we had auction rate securities (ARSs) with a par value of $71.3 million and $73.8 million, respectively, and an estimated fair value of $65.1 million and $69.0 million, respectively, which are classified as long-term investments. All of our ARSs are backed by pools of student loans guaranteed by the U.S. Department of Education. As of April 29, 2011, we recorded cumulative net temporary impairment charges of $4.1 million within AOCI. In addition, we recorded other-than-temporary impairment charges of $2.1 million in other income (expense), net, during fiscal 2009 based on an analysis of the fair value and marketability of these investments. We estimated the fair value for each individual ARS using an income (discounted cash flow) approach that incorporates both observable and unobservable inputs to discount the expected future cash flows. Key inputs into the discounted cash flow analysis include managements' expectation of when the principal amount will be recovered either through redemption at par, or some other refinancing event by the issuer; and marketability adjustments. Based on our ability to access our cash and other short-term investments, our expected operating cash flows, and our other sources of cash, we do not intend to sell these investments prior to recovery of value. We will continue to monitor our ARS investments in light of the current debt market environment and evaluate our accounting for these investments.
Primary Fund [Member]
Par value of money market fund			60.9
Total realized gains (losses) included in earnings	0	(0.2)
Amount of investments purchased, sold or settled	0	51.4
Fair value, measurement with unobservable inputs	0	0	51.6
Privately-Held Companies [Member]
Total realized gains (losses) included in earnings	0	2.6	(6.3)
Amount of investments purchased, sold or settled	0	4.5
Fair value, measurement with unobservable inputs	0	0	1.9
Private Equity Fund [Member]
Total realized gains (losses) included in earnings	(0.1)	0.8
Amount of investments purchased, sold or settled	0	1.4
Fair value, measurement with unobservable inputs	1.3	1.4	2.0
Auction Rate Securities [Member]
Total realized gains (losses) included in earnings	0	0	(2.1)
Amount of investments purchased, sold or settled	2.5	1.7
Auction rate securities, par value	71.3	73.8
Fair value, measurement with unobservable inputs	65.1	69.0	66.5
Cumulative net temporary loss within AOCI	$ 4.1

Gross appreciation or the gross loss in value of the total unsold securities, after tax, attributable to the parent entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=6921628&loc=SL4569616-111683

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=6921930&loc=SL4573702-111684

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 30
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 29
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=6921628&loc=SL4569643-111683

+ Details