Financing Receivables and Operating Leases (Summary of Allowances for Credit Loss and Related Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Apr. 28, 2018	Apr. 29, 2017	Apr. 28, 2018	Apr. 29, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	$ 272	$ 378	$ 295	$ 375
Provisions	(8)	(1)	(34)	8
Recoveries (write-offs), net		(9)		(15)
Foreign exchange and other	(2)	1	1	1
Allowance for credit loss as of end of period	262	369	262	369
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	165	225	162	230
Provisions	1	3	2	1
Foreign exchange and other	(1)	0	1	(1)
Allowance for credit loss as of end of period	165	220	165	220
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	94	106	103	97
Provisions	(8)	10	(19)	22
Foreign exchange and other	(1)	1	1	2
Allowance for credit loss as of end of period	85	117	85	117
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	13	47	30	48
Provisions	(1)	(14)	(17)	(15)
Foreign exchange and other	0	0	(1)	0
Allowance for credit loss as of end of period	12	32	12	32
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period			162
Recoveries (write-offs), net		(8)		(10)
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		0		(4)
Allowance for credit loss as of end of period	85		85
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		$ (1)		$ (1)
Allowance for credit loss as of end of period	$ 12		$ 12

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

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- Definition

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

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- Definition

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

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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://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

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