Financing Receivables and Operating Leases (Summary of Allowances for Credit Loss and Related Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jan. 27, 2018	Jan. 28, 2017	Jan. 27, 2018	Jan. 28, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	$ 289	$ 386	$ 295	$ 375
Provisions	(20)	1	(26)	9
Recoveries (write-offs), net		(6)		(6)
Foreign exchange and other	3	(3)	3	0
Allowance for credit loss as of end of period	272	378	272	378
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	160	227	162	230
Provisions	3	2	1	(2)
Foreign exchange and other	2	(2)	2	(1)
Allowance for credit loss as of end of period	165	225	165	225
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	106	111	103	97
Provisions	(13)	0	(11)	12
Foreign exchange and other	1	(1)	2	1
Allowance for credit loss as of end of period	94	106	94	106
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	23	48	30	48
Provisions	(10)	(1)	(16)	(1)
Foreign exchange and other	0	0	(1)	0
Allowance for credit loss as of end of period	13	47	13	47
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period			162
Recoveries (write-offs), net		(2)		(2)
Allowance for credit loss as of end of period	165		165
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period			103
Recoveries (write-offs), net		(4)		(4)
Allowance for credit loss as of end of period	94		94
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period			30
Recoveries (write-offs), net		$ 0		$ 0
Allowance for credit loss as of end of period	$ 13		$ 13

Amount of gain (loss) from converting allowance reserve for credit loss to currency of reporting entity from amount denominated or measured in a different currency, which decreases (increases) the allowance for loan and lease losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesForeignCurrencyTranslation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_ProvisionForLoanLeaseAndOtherLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_FinanceReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_LoansReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=csco_FinancedServiceContractsAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_FinanceReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_LoansReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=csco_FinancedServiceContractsAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: