Derivative Instruments (Additional Information) (Details) number in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Apr. 30, 2016 USD ($)	Apr. 30, 2016 USD ($)	Jul. 25, 2015 USD ($)
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	$ 345	$ 345	$ 218
Net derivative gains or losses to be reclassified from AOCI into earnings in next twelve months	9
Description of Interest Rate Derivative Activities		In fiscal 2016, the Company did not enter into any interest rate swaps. In prior fiscal years, the Company entered into interest rate swaps designated as fair value hedges related to fixed-rate senior notes that are due in fiscal years 2017 through 2025.
Net liability position	$ 4	$ 4	$ 12
Derivatives designated as cash flow hedging instruments:
Derivative [Line Items]
Foreign currency cash flow hedges maturity period, maximum, months	18 months
Net investment hedging instruments
Derivative [Line Items]
Foreign currency cash flow hedges maturity period, maximum, months	6 months
Fixed Income Securities [Member]
Derivative [Line Items]
Number of Interest Rate Derivatives Held	0	0	0