Comprehensive Income (Loss) (AOCI components) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 28, 2018	Apr. 29, 2017	Apr. 28, 2018	Apr. 29, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period			$ 66,137
Other comprehensive income (loss)	$ (732)	$ 452	(695)	$ (15)
Balance, end of period	46,661		46,661
Net Unrealized Gains (Losses) on Available-for-Sale Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period			373	413
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.			(620)	(298)
(Gains) losses reclassified out of AOCI			(108)	91
Tax benefit (expense)			24	91
Other comprehensive income (loss)			(704)	(116)
Effect of adoption of accounting standard			54
Balance, end of period	(277)	297	(277)	297
Net Unrealized Gains (Losses) Cash Flow Hedging Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period			32	(59)
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.			28	(23)
(Gains) losses reclassified out of AOCI			(59)	66
Tax benefit (expense)			4	(6)
Other comprehensive income (loss)			(27)	37
Effect of adoption of accounting standard			0
Balance, end of period	5	(22)	5	(22)
Cumulative Translation Adjustment and Actuarial Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period			(359)	(680)
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.			34	69
(Gains) losses reclassified out of AOCI			5	1
Tax benefit (expense)			(3)	(7)
Other comprehensive income (loss)			36	63
Effect of adoption of accounting standard			(9)
Balance, end of period	(332)	(617)	(332)	(617)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period			46	(326)
Other comprehensive income (loss) before reclassifications attributable to Cisco Systems, Inc.			(558)	(252)
(Gains) losses reclassified out of AOCI			(162)	158
Tax benefit (expense)			25	78
Other comprehensive income (loss)			(695)	(16)
Effect of adoption of accounting standard			45
Balance, end of period	$ (604)	$ (342)	$ (604)	$ (342)