Stockholders' Equity - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Jan. 23, 2015	Jan. 24, 2014	Jan. 23, 2015	Jan. 24, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	$ 774.9us-gaap_OperatingExpenses	$ 775.6us-gaap_OperatingExpenses	$ 2,343.1us-gaap_OperatingExpenses	$ 2,366.6us-gaap_OperatingExpenses
Other income (expense), net	0.1us-gaap_OtherNonoperatingIncomeExpense	1.7us-gaap_OtherNonoperatingIncomeExpense	(0.2)us-gaap_OtherNonoperatingIncomeExpense	6.9us-gaap_OtherNonoperatingIncomeExpense
Net revenues	1,551.3us-gaap_SalesRevenueNet	1,610.0us-gaap_SalesRevenueNet	4,583.0us-gaap_SalesRevenueNet	4,676.1us-gaap_SalesRevenueNet
Net income	176.8us-gaap_NetIncomeLoss	192.1us-gaap_NetIncomeLoss	425.0us-gaap_NetIncomeLoss	440.5us-gaap_NetIncomeLoss
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(15.9)	(0.2)	(9.3)	0.1
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	0.3	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	(0.3)	0	(0.1)	(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	$ (15.7)	$ (0.2)	$ (9.5)	$ 1.2

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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The net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income (expense) recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) net gains or losses on securities, (d) unusual costs, (e) gains or losses on foreign exchange transactions, and (f) miscellaneous other income and expense items.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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