Stockholders Equity - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 24, 2014	Oct. 25, 2013	Oct. 24, 2014	Oct. 25, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	$ 790.0	$ 778.3	$ 1,568.2	$ 1,591.0
Other income (expense), net	(0.8)	3.3	(0.3)	5.2
Net revenues	1,542.5	1,549.9	3,031.7	3,066.1
Net income	159.8	166.8	248.2	248.4
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	4.6	1.4	6.6	0.3
Reclassification out of Accumulated Other Comprehensive Income | Defined Benefit Obligation Adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	0.1	0	0.2	0
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains on Available-for-Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net	0	(1.0)	0.2	(1.1)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net revenues	$ 4.5	$ 2.4	$ 6.2	$ 1.4