Restructuring and Other Charges - Activities Related to Restructuring Reserves (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 25, 2014	Apr. 26, 2013	Apr. 27, 2012
Restructuring Cost and Reserve [Line Items]
Net charges	$ 88.3	$ 0	$ 0
Cash payments	(61.8)
Ending balance, reserve	26.5
May 2013 Restructuring
Restructuring Cost and Reserve [Line Items]
Net charges	49.5
Cash payments	(49.5)
Ending balance, reserve	0
March 2014 Restructuring
Restructuring Cost and Reserve [Line Items]
Net charges	38.8
Cash payments	(12.3)
Ending balance, reserve	$ 26.5