Fair Value (Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Millions	Apr. 27, 2019	Jul. 28, 2018
Fair Value Measurements [Line Items]
Available-for-sale debt investments	$ 24,387	$ 37,009
Marketable equity securities	5	605
Derivative assets	36	2
Derivative liabilities	20	74
U.S. government securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	1,452	7,275
U.S. government agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	263	727
Non-U.S. government and agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments		208
Corporate debt securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	21,232	27,364
Fair Value, Measurements, Recurring
Fair Value Measurements [Line Items]
Marketable equity securities	5	605
Derivative assets	36	2
Total	32,711	44,506
Derivative liabilities	20	74
Total	20	74
Fair Value, Measurements, Recurring \| U.S. government securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	1,452	7,275
Fair Value, Measurements, Recurring \| U.S. government agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	263	727
Fair Value, Measurements, Recurring \| Non-U.S. government and agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	208
Fair Value, Measurements, Recurring \| Corporate debt securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	21,232	27,364
Fair Value, Measurements, Recurring \| U.S. agency mortgage-backed securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	1,440	1,435
Fair Value, Measurements, Recurring \| Money market funds
Fair Value Measurements [Line Items]
Cash equivalents:	8,283	6,890
Fair Value, Measurements, Recurring \| Level 1
Fair Value Measurements [Line Items]
Marketable equity securities	5	605
Derivative assets	0	0
Total	8,288	7,495
Derivative liabilities	0	0
Total	0	0
Fair Value, Measurements, Recurring \| Level 1 \| U.S. government securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	0
Fair Value, Measurements, Recurring \| Level 1 \| U.S. government agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	0
Fair Value, Measurements, Recurring \| Level 1 \| Non-U.S. government and agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	0
Fair Value, Measurements, Recurring \| Level 1 \| Corporate debt securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	0
Fair Value, Measurements, Recurring \| Level 1 \| U.S. agency mortgage-backed securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	0
Fair Value, Measurements, Recurring \| Level 1 \| Money market funds
Fair Value Measurements [Line Items]
Cash equivalents:	8,283	6,890
Fair Value, Measurements, Recurring \| Level 2
Fair Value Measurements [Line Items]
Marketable equity securities	0	0
Derivative assets	36	2
Total	24,423	37,011
Derivative liabilities	20	74
Total	20	74
Fair Value, Measurements, Recurring \| Level 2 \| U.S. government securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	1,452	7,275
Fair Value, Measurements, Recurring \| Level 2 \| U.S. government agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	263	727
Fair Value, Measurements, Recurring \| Level 2 \| Non-U.S. government and agency securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	0	208
Fair Value, Measurements, Recurring \| Level 2 \| Corporate debt securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	21,232	27,364
Fair Value, Measurements, Recurring \| Level 2 \| U.S. agency mortgage-backed securities
Fair Value Measurements [Line Items]
Available-for-sale debt investments	1,440	1,435
Fair Value, Measurements, Recurring \| Level 2 \| Money market funds
Fair Value Measurements [Line Items]
Cash equivalents:	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value of financial and nonfinancial obligations.

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