Stockholders Equity - Activity Related to Stock Options (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
	Jan. 24, 2014
Number of Shares
Outstanding as of April 26, 2013, Number of Shares	19.2
Options granted, Number of Shares	2.7
Options Exercised, Number of Shares	(5.7)
Options forfeited and expired, Number of Shares	(1.1)
Outstanding as of January 24, 2014, Number of Shares	15.1
Options vested and expected to vest, Number of Shares	14.6
Options Exercisable, Number of Shares	10.7
Weighted-Average Exercise Price
Beginning Balance, Weighted-Average Exercise Price	$ 31.27
Options granted, Weighted-Average Exercise Price	$ 38.28
Options exercised, Weighted-Average Exercise Price	$ 25.91
Options forfeited and expired, Weighted-Average Exercise Price	$ 42.04
Ending Balance, Weighted-Average Exercise Price	$ 33.79
Options vested and expected to vest, Weighted-Average Exercise Price	$ 33.67
Options Exercisable, Weighted-Average Exercise Price	$ 31.86
Weighted-Average Remaining Contractual Term
Outstanding, Weighted-Average Remaining Contractual Term	3 years 7 months 13 days
Options vested and expected to vest, Weighted-Average Remaining Contractual Term	3 years 6 months 15 days
Exercisable, Weighted-Average Remaining Contractual Term	2 years 9 months 7 days
Aggregate Intrinsic Value
Outstanding, Aggregate Intrinsic Value	$ 176.6
Options vested and expected to vest, Aggregate Intrinsic Value	173.0
Exercisable, Aggregate Intrinsic Value	$ 145.9