Financing Receivables and Operating Leases (Summary of Allowances for Credit Loss and Related Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended
Oct. 27, 2018	Oct. 28, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	$ 205	$ 295
Provisions	(5)	(6)
Foreign exchange and other	(1)	0
Allowance for credit loss as of end of period	199	289
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	135	162
Provisions	(3)	(2)
Foreign exchange and other	(1)	0
Allowance for credit loss as of end of period	131	160
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	60	103
Provisions	0	2
Foreign exchange and other	0	1
Allowance for credit loss as of end of period	60	106
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	10	30
Provisions	(2)	(6)
Foreign exchange and other	0	(1)
Allowance for credit loss as of end of period	8	$ 23
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	135
Allowance for credit loss as of end of period	131
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	60
Allowance for credit loss as of end of period	60
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	10
Allowance for credit loss as of end of period	$ 8

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://fasb.org/us-gaap/role/ref/legacyRef
-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

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-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

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- Definition

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

+ References

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- 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.

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- 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://fasb.org/us-gaap/role/ref/legacyRef
-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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

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