Borrowings (Schedule of Long-Term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
Oct. 27, 2018	Jul. 28, 2018
Debt Instrument [Line Items]
Total	$ 25,750	$ 25,750
Unaccreted discount/issuance costs	(112)	(116)
Hedge accounting fair value adjustments	(74)	(65)
Total	25,564	25,569
Current portion of long-term debt	7,241	5,238
Long-term debt	18,323	20,331
Floating Rate Notes 3-month Libor Plus 0.50% Due March 2019
Debt Instrument [Line Items]
Amount	$ 500	$ 500
Effective Rate	2.88%	2.86%
Floating Rate Notes 3-month Libor Plus 0.34% Due September 2019
Debt Instrument [Line Items]
Amount	$ 500	$ 500
Effective Rate	2.72%	2.71%
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	5.22%	5.17%
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	2.87%	2.71%
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	4.68%	4.52%
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	3.05%	2.86%
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	3.32%	3.11%
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	3.17%	2.98%
Fixed-Rate Notes, 3.50%, Due June 15, 2025
Debt Instrument [Line Items]
Interest rate, stated percentage	3.50%
Amount	$ 500	$ 500
Effective Rate	3.48%	3.27%
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%
LIBOR \| Floating Rate Notes 3-month Libor Plus 0.50% Due March 2019
Debt Instrument [Line Items]
Three-month LIBOR plus this percentage	0.50%
LIBOR \| Floating Rate Notes 3-month Libor Plus 0.34% Due September 2019
Debt Instrument [Line Items]
Three-month LIBOR plus this percentage	0.34%

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