Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 2,394	$ 2,322
Available-for-sale investments:
Change in net unrealized gains and losses, net of tax benefit (expense) of $(23) and $81 for the three months ended October 28, 2017 and October 29, 2016, respectively	(5)	(121)
Net (gains) losses reclassified into earnings, net of tax (benefit) expense of $10 and $5 for the three months ended October 28, 2017 and October 29, 2016, respectively	(23)	(10)
Total- Available-for-sale investments	(28)	(131)
Cash flow hedging instruments:
Change in unrealized gains and losses, net of tax benefit (expense) of $(1) and $3 for the three months ended October 28, 2017 and October 29, 2016, respectively	7	(43)
Net (gains) losses reclassified into earnings, net of tax (benefit) expense of $2 and $(1) for the three months ended October 28, 2017 and October 29, 2016, respectively	(11)	11
Total- Cash flow hedging instruments	(4)	(32)
Net change in cumulative translation adjustment and actuarial gains and losses net of tax benefit (expense) of $(2) and $(1) for the three months ended October 28, 2017 and October 29, 2016, respectively	17	(27)
Other comprehensive income (loss)	(15)	(190)
Comprehensive income	2,379	2,132
Comprehensive (income) loss attributable to noncontrolling interests	0	(8)
Comprehensive income attributable to Cisco Systems, Inc.	$ 2,379	$ 2,124