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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.

+ References

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- Definition

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

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-Subparagraph (c)(1)(i)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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.

+ References

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Employee Stock Plans (Summary Of Significant Ranges Of Outstanding And Exercisable Stock Options) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	6 Months Ended
	Jan. 26, 2013	Jul. 28, 2012	Jul. 27, 2012	Jul. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	419	520		621
Stock options outstanding, weighted-average remaining contractual life (in years)	2 years 5 months 8 days
Stock options outstanding, weighted-average exercise price per share	$ 23.08	$ 22.68		$ 21.79
Stock options outstanding, aggregate intrinsic value	$ 590
Stock options exercisable	413	512
Stock options exercisable, weighted-average exercise price per share	$ 23.31		$ 22.65
Stock options exercisable, aggregate intrinsic value	500
$0.01 - 15.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	11
Stock options outstanding, weighted-average remaining contractual life (in years)	5 years 9 months 18 days
Stock options outstanding, weighted-average exercise price per share	$ 4.83
Stock options outstanding, aggregate intrinsic value	181
Stock options exercisable	7
Stock options exercisable, weighted-average exercise price per share	$ 7.20
Stock options exercisable, aggregate intrinsic value	91
$15.01 - 18.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	69
Stock options outstanding, weighted-average remaining contractual life (in years)	1 year 7 months 28 days
Stock options outstanding, weighted-average exercise price per share	$ 17.79
Stock options outstanding, aggregate intrinsic value	232
Stock options exercisable	69
Stock options exercisable, weighted-average exercise price per share	$ 17.79
Stock options exercisable, aggregate intrinsic value	231
$18.01 - 20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	86
Stock options outstanding, weighted-average remaining contractual life (in years)	10 months 10 days
Stock options outstanding, weighted-average exercise price per share	$ 19.17
Stock options outstanding, aggregate intrinsic value	170
Stock options exercisable	86
Stock options exercisable, weighted-average exercise price per share	$ 19.17
Stock options exercisable, aggregate intrinsic value	170
$20.01 - 25.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	129
Stock options outstanding, weighted-average remaining contractual life (in years)	2 years 5 months 23 days
Stock options outstanding, weighted-average exercise price per share	$ 22.77
Stock options outstanding, aggregate intrinsic value	7
Stock options exercisable	128
Stock options exercisable, weighted-average exercise price per share	$ 22.77
Stock options exercisable, aggregate intrinsic value	8
$25.01 - 35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	124
Stock options outstanding, weighted-average remaining contractual life (in years)	3 years 7 months 13 days
Stock options outstanding, weighted-average exercise price per share	$ 30.69
Stock options outstanding, aggregate intrinsic value	0
Stock options exercisable	123
Stock options exercisable, weighted-average exercise price per share	$ 30.71
Stock options exercisable, aggregate intrinsic value	$ 0