Financing Arrangements (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	Jun. 10, 2008	Apr. 27, 2012	Apr. 29, 2011	Apr. 30, 2010
Debt Instrument [Line Items]
Number of business days after measurement period		5
Convertible notes, measurement period for conversion, days		5
Note repurchase price, percentage of principal amount of notes		100.00%
Trading price of convertible notes during measurement period, maximum percentage		98.00%
Trading price of convertible notes during measurement period, percentage		130.00%
Effective interest rate	6.31%
Debt discounts	$ 248,000,000
Conversion price of notes to shares of common stock		$ 31.85
Closing price of common stock		39.03
Note hedges number of shares contracted to sell		31,800,000	31,800,000
Note hedge exercise price		$ 31.85	$ 31.85
Unhedged portion of notes		20.00%
Fair value of notes	1,017,000,000	1,649,900,000
Fair value percentage of face value of senior debt		130.00%
Settlement (purchase) of note hedge		0	0	14,200,000
Equity Component [Member]
Debt Instrument [Line Items]
Issuance costs on equity	5,200,000
Liability Component [Member]
Debt Instrument [Line Items]
Issuance costs on equity	21,400,000
Convertible Senior Notes 1.75% [Member]
Debt Instrument [Line Items]
Senior notes	1,265,000,000	1,264,900,000	1,265,000,000
Senior notes, stated annual interest rate percentage	1.75%
Senior notes, maturity date		Jun. 01, 2013
Numerator of common stock ratio for convertible notes		31.40
Denominator of principal amount upon which conversion rate is based		1,000
Debt discounts		62,600,000	114,600,000
Conversion price of notes to shares of common stock		$ 31.85
Debt instrument, convertible, if-converted value in excess of principal		$ 285,300,000
Warrant [Member]
Debt Instrument [Line Items]
Outstanding warrants, number of shares		39,700,000	39,700,000
Exercise price of warrants		41.28	41.28