Financing Receivables And Guarantees (Schedule Of Financing Receivables Categorized By Internal Credit Risk Rating) (Details) (USD $) In Millions, unless otherwise specified	Apr. 28, 2012	Jul. 30, 2011
Internal Credit Risk Rating 1 To 4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	$ 3,958	$ 3,534
Internal Credit Risk Rating 1 To 4 [Member] | Lease Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	1,535	1,249
Internal Credit Risk Rating 1 To 4 [Member] | Loan Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	830	662
Internal Credit Risk Rating 1 To 4 [Member] | Financed Service Contracts & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	1,593	1,623
Internal Credit Risk Rating 5 To 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	3,221	3,000
Internal Credit Risk Rating 5 To 6 [Member] | Lease Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	1,302	1,275
Internal Credit Risk Rating 5 To 6 [Member] | Loan Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	942	767
Internal Credit Risk Rating 5 To 6 [Member] | Financed Service Contracts & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	977	958
Internal Credit Risk Rating 7 And Higher [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	139	136
Internal Credit Risk Rating 7 And Higher [Member] | Lease Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	26	41
Internal Credit Risk Rating 7 And Higher [Member] | Loan Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	55	39
Internal Credit Risk Rating 7 And Higher [Member] | Financed Service Contracts & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	58	56
Total Internal Credit Risk Rating [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	7,318	6,670
Total Internal Credit Risk Rating [Member] | Lease Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	2,863	2,565
Total Internal Credit Risk Rating [Member] | Loan Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	1,827	1,468
Total Internal Credit Risk Rating [Member] | Financed Service Contracts & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	2,628	2,637
Residual Value [Member]
Financing Receivable, Recorded Investment [Line Items]
Residual Value	290	296
Residual Value [Member] | Lease Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Residual Value	290	296
Gross Receivables, Net Of Unearned Income [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	7,608	6,966
Gross Receivables, Net Of Unearned Income [Member] | Lease Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	3,153	2,861
Gross Receivables, Net Of Unearned Income [Member] | Loan Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	1,827	1,468
Gross Receivables, Net Of Unearned Income [Member] | Financed Service Contracts & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross receivables net of unearned income	$ 2,628	$ 2,637