Financing Receivables and Operating Leases (Additional Information) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jan. 24, 2015		Jan. 24, 2015 Rating		Jul. 26, 2014	Jan. 25, 2014
Financing Receivables And Guarantees [Line Items]
Average lease term (in years)	4 years
Deferred revenue:	$ 14,021,000,000		$ 14,021,000,000		$ 14,142,000,000
Financing receivable, allowance for credit loss and deferred revenue	1,928,000,000		1,928,000,000		2,220,000,000
Total financing receivables before allowance for credit loss	8,134,000,000	[1]	8,134,000,000	[1]	8,420,000,000	8,018,000,000	[1]
Threshold for past due receivables (in days)	31 days
Unbilled or current financing receivables included in greater than 91 days plus past due	542,000,000		542,000,000		334,000,000
Financing Receivable, 90 Days Past Due and Still Accruing	217,000,000		217,000,000		78,000,000
Operating Leases, Future Minimum Payments, Remainder of Fiscal Year	100,000,000		100,000,000
Minimum future rental from operating leases (per year amount in Fiscal 2016)	200,000,000		200,000,000
Investment Credit Risk Ratings Range Lowest			1
Investment Credit Risk Ratings Range Highest			10
Rating at or higher when receivables deemed impaired			8
Maximum
Financing Receivables And Guarantees [Line Items]
Loan receivables term (in years)	3 years
Minimum future rentals from operating leases (per year amount in Fiscal 2017)	100,000,000		100,000,000
Minimum future rentals from operating leases (per year amount in Fiscal 2018)	100,000,000		100,000,000
Minimum future rentals from operating leases (per year amount in Fiscal 2019)	100,000,000		100,000,000
Financed Service Contracts and Other | Minimum
Financing Receivables And Guarantees [Line Items]
Financed service contracts term (in years)	1 year
Financed Service Contracts and Other | Maximum
Financing Receivables And Guarantees [Line Items]
Financed service contracts term (in years)	3 years
Investment-grade ratings | Minimum
Financing Receivables And Guarantees [Line Items]
Financing credit risk rating-investment-lowest	1
Investment-grade ratings | Maximum
Financing Receivables And Guarantees [Line Items]
Financing credit risk rating-investment-lowest	4
Non-investment grade ratings | Minimum
Financing Receivables And Guarantees [Line Items]
Financing credit risk rating-investment-lowest	5
Non-investment grade ratings | Maximum
Financing Receivables And Guarantees [Line Items]
Financing credit risk rating-investment-lowest	6
Substandard | Minimum
Financing Receivables And Guarantees [Line Items]
Financing credit risk rating-investment-lowest	7
Lease Receivables
Financing Receivables And Guarantees [Line Items]
Total financing receivables before allowance for credit loss	3,391,000,000	[1]	3,391,000,000	[1]		3,551,000,000	[1]
Loan Receivables
Financing Receivables And Guarantees [Line Items]
Total financing receivables before allowance for credit loss	1,674,000,000	[1]	1,674,000,000	[1]		1,660,000,000	[1]
Financed Service Contracts and Other
Financing Receivables And Guarantees [Line Items]
Deferred revenue:	1,530,000,000		1,530,000,000		1,843,000,000
Total financing receivables before allowance for credit loss	$ 3,069,000,000	[1]	$ 3,069,000,000	[1]		$ 2,807,000,000	[1]

[1] Total financing receivables before allowance for credit loss.