Comprehensive Income (AOCI components) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 29, 2016	Oct. 24, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of period	$ 63,586
Balance, end of period	63,406
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.	(210)	(155)
(Gains) losses reclassified out of AOCI	(15)	1
Tax benefit (expense)	86	56
Balance, end of period	274	212
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.	(46)	(4)
(Gains) losses reclassified out of AOCI	12	3
Tax benefit (expense)	2	2
Balance, end of period	(91)	(15)
Cumulative Translation Adjustment and Actuarial Gains and 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.	(26)	(178)
(Gains) losses reclassified out of AOCI	0	1
Tax benefit (expense)	(1)	(39)
Balance, end of period	(707)	(449)
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.	(282)	(337)
(Gains) losses reclassified out of AOCI	(3)	5
Tax benefit (expense)	87	19
Balance, end of period	$ (524)	$ (252)