Comprehensive Income (Reclassification out of other comprehensive income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 25, 2015	Apr. 30, 2016	Apr. 25, 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	$ (6)	$ 44	$ (26)	$ 120
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	(9)	(64)	(17)	(94)
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	(7)	(50)	(13)	(74)
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	(2)	(14)	(4)	(20)
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	(1)	0	(2)	0
Total Cisco Shareholders’ Equity
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total amounts reclassified out of AOCI	$ (16)	$ (20)	$ (45)	$ 26