Employee Benefit Plans - Valuation of Employee Share-Based Awards - Time-Based Restricted Stock Units (Details) - $ / shares shares in Millions	12 Months Ended
Jul. 25, 2020	Jul. 27, 2019	Jul. 28, 2018
RESTRICTED STOCK UNITS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted (in shares)	47	43	43
Grant date fair value per share (in dollars per share)	$ 42.68	$ 47.75	$ 35.81
Expected dividend	3.10%	2.70%	3.20%
Range of risk-free interest rates, minimum	0.00%	0.00%	0.00%
Range of risk-free interest rates, maximum	2.00%	2.90%	2.70%
PERFORMANCE BASED RESTRICTED STOCK UNITS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted (in shares)	2	2	3
Grant date fair value per share (in dollars per share)	$ 41.91	$ 47.00	$ 32.69
Expected dividend	2.80%	2.80%	3.50%
Range of risk-free interest rates, minimum	1.70%	2.10%	1.00%
Range of risk-free interest rates, maximum	2.00%	3.00%	2.70%
Range of expected volatilities for index, minimum	13.70%	13.00%	12.50%
Range of expected volatilities for index, maximum	69.00%	65.20%	82.80%

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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