Borrowings (Schedule of Long-Term Debt) (Details) - USD ($) $ in Millions	9 Months Ended
Apr. 28, 2018	Jul. 29, 2017
Debt Instrument [Line Items]
Total	$ 28,250	$ 30,500
Unaccreted discount/issuance costs	(119)	(136)
Hedge accounting fair value adjustments	(59)	108
Total	28,072	30,472
Current portion of long-term debt	7,736	4,747
Long-term debt	20,336	25,725
Floating Rate Notes 3-month Libor Plus 0.60% Due February 2018
Debt Instrument [Line Items]
Amount	$ 0	$ 1,000
Effective Rate	0.00%	1.84%
Floating Rate Notes 3-month Libor Plus 0.31% Due June 2018
Debt Instrument [Line Items]
Amount	$ 900	$ 900
Effective Rate	2.50%	1.62%
Floating Rate Notes 3-month Libor Plus 0.50% Due March 2019
Debt Instrument [Line Items]
Amount	$ 500	$ 500
Effective Rate	2.57%	1.76%
Floating Rate Notes 3-month Libor Plus 0.34% Due September 2019
Debt Instrument [Line Items]
Amount	$ 500	$ 500
Effective Rate	2.58%	1.66%
Fixed Rate Notes, 1.40%, Due February 28, 2018
Debt Instrument [Line Items]
Interest rate, stated percentage	1.40%
Amount	$ 0	$ 1,250
Effective Rate	0.00%	1.47%
Fixed rate notes 1.65% due June 2018
Debt Instrument [Line Items]
Interest rate, stated percentage	1.65%
Amount	$ 1,600	$ 1,600
Effective Rate	1.72%	1.72%
Fixed-Rate Notes, 4.95%, Due February 2019
Debt Instrument [Line Items]
Interest rate, stated percentage	4.95%
Amount	$ 2,000	$ 2,000
Effective Rate	5.12%	4.96%
Fixed-Rate Notes, 1.60%, Due February 2019
Debt Instrument [Line Items]
Interest rate, stated percentage	1.60%
Amount	$ 1,000	$ 1,000
Effective Rate	1.67%	1.67%
Fixed-Rate Notes, 2.125%, Due March 2019
Debt Instrument [Line Items]
Interest rate, stated percentage	2.125%
Amount	$ 1,750	$ 1,750
Effective Rate	2.50%	1.84%
Fixed-Rate Notes, 1.40%, Due September 2019
Debt Instrument [Line Items]
Interest rate, stated percentage	1.40%
Amount	$ 1,500	$ 1,500
Effective Rate	1.48%	1.48%
Fixed-Rate Notes, 4.45%, Due January 2020
Debt Instrument [Line Items]
Interest rate, stated percentage	4.45%
Amount	$ 2,500	$ 2,500
Effective Rate	4.38%	3.84%
Fixed-Rate Notes, 2.45%, Due June 2020
Debt Instrument [Line Items]
Interest rate, stated percentage	2.45%
Amount	$ 1,500	$ 1,500
Effective Rate	2.54%	2.54%
Fixed-Rate Notes, 2.20%, Due February 2021
Debt Instrument [Line Items]
Interest rate, stated percentage	2.20%
Amount	$ 2,500	$ 2,500
Effective Rate	2.30%	2.30%
Fixed-Rate Notes, 2.90%, Due March 2021
Debt Instrument [Line Items]
Interest rate, stated percentage	2.90%
Amount	$ 500	$ 500
Effective Rate	2.66%	2.00%
Fixed-Rate Notes, 1.85%, Due September 2021
Debt Instrument [Line Items]
Interest rate, stated percentage	1.85%
Amount	$ 2,000	$ 2,000
Effective Rate	1.90%	1.90%
Fixed-Rate Notes, 3.00 %, Due June 15, 2022
Debt Instrument [Line Items]
Interest rate, stated percentage	3.00%
Amount	$ 500	$ 500
Effective Rate	2.94%	2.26%
Fixed-Rate Notes, 2.60%, Due February, 2023
Debt Instrument [Line Items]
Interest rate, stated percentage	2.60%
Amount	$ 500	$ 500
Effective Rate	2.68%	2.68%
Fixed-Rate Notes, 2.20%, Due September 2023
Debt Instrument [Line Items]
Interest rate, stated percentage	2.20%
Amount	$ 750	$ 750
Effective Rate	2.27%	2.27%
Fixed-Rate Notes, 3.625%, Due March 2024
Debt Instrument [Line Items]
Interest rate, stated percentage	3.625%
Amount	$ 1,000	$ 1,000
Effective Rate	2.78%	2.12%
Fixed-Rate Notes, 3.50%, Due June 15, 2025
Debt Instrument [Line Items]
Interest rate, stated percentage	3.50%
Amount	$ 500	$ 500
Effective Rate	3.10%	2.43%
Fixed-Rate Notes,2.95%, Due February, 2026
Debt Instrument [Line Items]
Interest rate, stated percentage	2.95%
Amount	$ 750	$ 750
Effective Rate	3.01%	3.01%
Fixed-Rate Notes, 2.50%, Due September 2026
Debt Instrument [Line Items]
Interest rate, stated percentage	2.50%
Amount	$ 1,500	$ 1,500
Effective Rate	2.55%	2.55%
Fixed-Rate Notes, 5.90%, Due February 2039
Debt Instrument [Line Items]
Interest rate, stated percentage	5.90%
Amount	$ 2,000	$ 2,000
Effective Rate	6.11%	6.11%
Fixed-Rate Notes, 5.50%, Due January 2040
Debt Instrument [Line Items]
Interest rate, stated percentage	5.50%
Amount	$ 2,000	$ 2,000
Effective Rate	5.67%	5.67%
One-month LIBOR plus \| Floating Rate Notes 3-month Libor Plus 0.60% Due February 2018
Debt Instrument [Line Items]
Three-month LIBOR plus this percentage	0.60%
One-month LIBOR plus \| Floating Rate Notes 3-month Libor Plus 0.31% Due June 2018
Debt Instrument [Line Items]
Three-month LIBOR plus this percentage	0.31%
One-month LIBOR plus \| Floating Rate Notes 3-month Libor Plus 0.50% Due March 2019
Debt Instrument [Line Items]
Three-month LIBOR plus this percentage	0.50%
One-month LIBOR plus \| Floating Rate Notes 3-month Libor Plus 0.34% Due September 2019
Debt Instrument [Line Items]
Three-month LIBOR plus this percentage	0.34%

Hedge accounting adjustment of the carrying amount of the 2011 and 2016 Notes

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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

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- Definition

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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No definition available.

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- Definition

Amount, after accumulated amortization, of debt discount.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
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-Subparagraph (SX 210.7-03(a)(16))
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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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