Short-term Borrowings and Long-term Debt (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
Jan. 26, 2020	Jan. 27, 2019
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	$ 1,200
Payments for Debt Extinguishment or Debt Prepayment Cost	1,765	$ 0
Debt Instrument, Repurchased Face Amount	1,691
Loss on extinguishment of debt	(75)	$ 0
Interest Expense [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt	(75)
Gain (Loss) on Extinguishment of Debt, before Write off of Debt Issuance Cost	(65)
4.25% notes, due 2021
Debt Instrument [Line Items]
Repayments of Debt	$ 500
Debt Instrument, Interest Rate, Stated Percentage	4.25%
3.65% notes, due 2023
Debt Instrument [Line Items]
Repayments of Debt	$ 634
Debt Instrument, Interest Rate, Stated Percentage	3.65%
3.80% notes, due 2042
Debt Instrument [Line Items]
Repayments of Debt	$ 237
Debt Instrument, Interest Rate, Stated Percentage	3.80%
3.3% notes, due 2021
Debt Instrument [Line Items]
Repayments of Debt	$ 329
Debt Instrument, Interest Rate, Stated Percentage	3.30%

Contractual interest rate for funds borrowed, under the debt agreement.

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Face (par) amount of the original debt instrument that was repurchased.

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Gross amount of debt extinguished.

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Reflects the difference between the fair value of payments made to legally extinguish a debt and its carrying value at that time. This item excludes the write-off of amounts previously capitalized as debt issuance costs.

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Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

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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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