Stockholders' Equity - Activity Related to Stock Options (Detail) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
Jan. 27, 2017 USD ($) $ / shares shares
Number of Shares
Beginning balance, Number of Shares \| shares	9
Options exercised, Number of Shares \| shares	(2)
Options forfeited and expired, Number of Shares \| shares	(2)
Ending balance, Number of Shares \| shares	5
Options Exercisable, Number of Shares \| shares	4
Weighted-Average Exercise Price
Beginning balance, Weighted-Average Exercise Price \| $ / shares	$ 34.01
Options exercised, Weighted-Average Exercise Price \| $ / shares	22.13
Options forfeited and expired, Weighted-Average Exercise Price \| $ / shares	39.44
Ending balance, Weighted-Average Exercise Price \| $ / shares	35.01
Options Exercisable, Weighted-Average Exercise Price \| $ / shares	$ 40.19
Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value
Outstanding, Weighted-Average Remaining Contractual Term	3 years 5 months 1 day
Exercisable, Weighted-Average Remaining Contractual Term	2 years 6 months
Outstanding, Aggregate Intrinsic Value \| $	$ 33
Exercisable, Aggregate Intrinsic Value \| $	$ 10

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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-Publisher FASB
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Weighted average price of options that were either forfeited or expired.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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