Investments (Summary Of Available-For-Sale Investments) (Details) (USD $) In Millions, unless otherwise specified	Jan. 24, 2015	Jul. 26, 2014
Available-for-sale investments: [Line Items]
Amortized Cost	$ 47,570	$ 44,619
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	695	759
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(40)	(30)
Fair Value	48,225us-gaap_AvailableForSaleSecurities	45,348us-gaap_AvailableForSaleSecurities
Total fixed income securities
Available-for-sale investments: [Line Items]
Amortized Cost	46,274	43,305
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	133	111
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(30)	(20)
Fair Value	46,377	43,396
Total fixed income securities \| U.S. government securities
Available-for-sale investments: [Line Items]
Amortized Cost	30,302	31,717
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	53	29
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(1)	(12)
Fair Value	30,354	31,734
Total fixed income securities \| U.S. government agency securities
Available-for-sale investments: [Line Items]
Amortized Cost	2,324	1,062
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	3	1
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(1)	0
Fair Value	2,326	1,063
Total fixed income securities \| Non-U.S. government and agency securities
Available-for-sale investments: [Line Items]
Amortized Cost	1,108	860
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	1	2
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	(1)
Fair Value	1,109	861
Total fixed income securities \| Corporate debt securities
Available-for-sale investments: [Line Items]
Amortized Cost	11,180	9,092
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	61	74
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(28)	(7)
Fair Value	11,213	9,159
Total fixed income securities \| U.S. agency mortgage-backed securities
Available-for-sale investments: [Line Items]
Amortized Cost	1,360	574
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	15	5
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Fair Value	1,375	579
Publicly traded equity securities [Member]
Available-for-sale investments: [Line Items]
Amortized Cost	1,296	1,314
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	562	648
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(10)	(10)
Fair Value	$ 1,848	$ 1,952

Name:	csco_AvailableForSaleInvestmentsLineItems
Namespace Prefix:	csco_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

+ Details

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=csco_PubliclytradedequitysecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_FixedIncomeInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: