Comprehensive Income (Reclassification out of other comprehensive income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jan. 24, 2015
Net Unrealized Gains on Available-for-Sale Investments | Other income (loss), net
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net unrealized gains on available-for-sale investments	$ (19)	$ 69	$ (20)	$ 76
Derivatives designated as cash flow hedging instruments:
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total amounts reclassified out of AOCI	(5)	(26)	(8)	(30)
Derivatives designated as cash flow hedging instruments: | Operating expenses
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total amounts reclassified out of AOCI	(4)	(21)	(6)	(24)
Derivatives designated as cash flow hedging instruments: | Cost of sales—service
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total amounts reclassified out of AOCI	(1)	(5)	(2)	(6)
Cumulative translation adjustment and Actuarial gains and losses [Member] | Operating expenses
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total amounts reclassified out of AOCI	0	0	(1)	0
Total Cisco Shareholders’ Equity
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total amounts reclassified out of AOCI	$ (24)	$ 43	$ (29)	$ 46