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Short-term Borrowing and Long-term Debt (Narratives) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Aug. 02, 2020	Apr. 26, 2020	Aug. 02, 2020	Jul. 28, 2019	Jul. 29, 2018
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount	$ 34		$ 34
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
Proceeds from Lines of Credit		$ 300
Debt, Current	1,202		1,202	$ 1,371
Extinguishment of Debt, Amount			1,200
Payment for Debt Extinguishment, Net			1,765
Gain (Loss) on Extinguishment of Debt			(75)	0	$ 0
Repayments of Long-term Debt			499	702	63
Long-term borrowings			1,000	0	$ 6,224
Repayments of Lines of Credit	300		300
Long-term Debt, Maturities, Repayments of Principal in Year Two	4		4
Long-term Debt, Maturities, Repayments of Principal in Year Three	1,019		1,019
Long-term Debt, Maturities, Repayments of Principal in Year Four	0		0
Long-term Debt, Maturities, Repayments of Principal in Year Five	1,150		1,150
Long-term Debt, Maturities, Repayments of Principal after Year Five	2,863		2,863
Long-term Debt and Lease Obligation	$ 4,994		4,994	7,103
Interest Expense [Member]
Debt Instrument [Line Items]
Gain (Loss) on Extinguishment of Debt			(75)
Gain (Loss) on Extinguishment of Debt, before Write off of Debt Issuance Cost			$ (65)
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Debt Instrument [Line Items]
Debt, Current				232
Long-term Debt and Lease Obligation				$ 6
Commercial Paper [Member]
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	2.10%		2.10%	2.97%
4.25% notes, due 2021
Debt Instrument [Line Items]
Repayments of Debt			$ 500
Debt Instrument, Interest Rate, Stated Percentage	4.25%		4.25%
Long-term Debt, Gross	$ 0		$ 0	$ 500
3.30% notes, due 2021
Debt Instrument [Line Items]
Repayments of Debt			$ 329
Debt Instrument, Interest Rate, Stated Percentage	3.30%		3.30%
Long-term Debt, Gross	$ 321		$ 321	650
3.65% notes, due 2023
Debt Instrument [Line Items]
Repayments of Debt			$ 634
Debt Instrument, Interest Rate, Stated Percentage	3.65%		3.65%
Long-term Debt, Gross	$ 566		$ 566	1,200
3.80% notes, due 2043
Debt Instrument [Line Items]
Repayments of Debt			$ 237
Debt Instrument, Interest Rate, Stated Percentage	3.80%		3.80%
Long-term Debt, Gross	$ 163		$ 163	400
Variable Interest Rate Senior Term Loan due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 0		0	499
Repayments of Long-term Debt			499
April 24, 2020 Debt Issuance Proceeds [Member]
Debt Instrument [Line Items]
Long-term borrowings			1,000
Proceeds from Issuance of Debt			$ 300
2.375% notes, due 2030
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.375%		2.375%
Long-term Debt, Gross	$ 500		$ 500	0
Debt Instrument, Redemption Price, Percentage			101.00%
3.125% notes, due 2050
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.125%		3.125%
Long-term Debt, Gross	$ 500		$ 500	$ 0
Debt Instrument, Redemption Price, Percentage			101.00%