Short-term Borrowing and Long-term Debt (Narratives) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Jul. 28, 2019	Jul. 28, 2019	Jul. 29, 2018	Apr. 29, 2018
Debt Instrument [Line Items]
Debt, Current	$ 1,371	$ 1,371	$ 1,525
Commercial Paper	853	853	1,140
Letters of Credit Outstanding, Amount	46	$ 46
Long-term Debt, Gross				$ 5,300
Debt Instrument, Redemption Price, Percentage		101.00%
Long-term Debt, Maturities, Repayments of Principal in Year Two	2,250	$ 2,250
Long-term Debt, Maturities, Repayments of Principal in Year Three	2	2
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,651	1,651
Long-term Debt, Maturities, Repayments of Principal in Year Five	1	1
Long-term Debt, Maturities, Repayments of Principal after Year Five	3,254	3,254
Long-term Debt and Capital Lease Obligations	$ 7,103	$ 7,103	$ 7,991
Commercial Paper [Member]
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	2.97%	2.97%	2.54%
Variable Interest Rate Term Loan due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 499	$ 499	$ 900	$ 900
Debt Instrument, Covenant Description		<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-left:4px;padding-bottom:6px;padding-top:6px;text-align:justify;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The senior unsecured term loan facility contains a financial covenant based on our maximum leverage ratio. Pursuant to this covenant, if our credit rating is less than BBB+ from Standard & Poor's and Baa1 from Moody's Investors Service, Inc and the amount borrowed under the facility is in excess of $500, we must maintain a leverage ratio below (i) for the last day of each quarter ending on or prior to April 30, 2020, 5.75:1.00, and (ii) thereafter, 5.25:1.00. Our leverage ratio is calculated based on the ratio of consolidated net debt to consolidated adjusted EBITDA, each as defined in the credit agreement for the senior unsecured term loan facility. In addition, the senior unsecured term loan facility contains other customary covenants and events of default for credit facilities of this type.</font></div></div>
Repayments of Debt	401
Domestic Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,850	$ 1,850
Line of Credit Facility, Expiration Date		Dec. 31, 2021
Line of Credit Facility Utilized Borrowing Capacity	1	$ 1
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Debt Instrument [Line Items]
Debt, Current	232	232	371
Long-term Debt and Capital Lease Obligations	$ 6	$ 6	$ 7

Amount of borrowing capacity currently utilized under the credit facility.

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Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the debt agreement. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants.

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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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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Date the credit facility terminates, in CCYY-MM-DD format.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Weighted average interest rate of short-term debt outstanding calculated at point in time.

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