Comprehensive Income (AOCI components) (Details) - USD ($) $ in Millions	9 Months Ended
	Apr. 29, 2017	Apr. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period	$ 63,586
Balance, end of period	65,382
Net Unrealized Gains (Losses) on Available-for-Sale Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period	413	$ 310
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.	(298)	(145)
(Gains) losses reclassified out of AOCI	91	26
Tax benefit (expense)	91	50
Balance, end of period	297	241
Net Unrealized Gains (Losses) Cash Flow Hedging Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period	(59)	(16)
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.	(23)	(3)
(Gains) losses reclassified out of AOCI	66	17
Tax benefit (expense)	(6)	(2)
Balance, end of period	(22)	(4)
Cumulative Translation Adjustment and Actuarial Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period	(680)	(233)
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.	69	(190)
(Gains) losses reclassified out of AOCI	1	2
Tax benefit (expense)	(7)	(43)
Balance, end of period	(617)	(464)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period	(326)	61
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.	(252)	(338)
(Gains) losses reclassified out of AOCI	158	45
Tax benefit (expense)	78	5
Balance, end of period	$ (342)	$ (227)