Financing Receivables And Guarantees (Schedule Of Financing Receivables Categorized By Internal Credit Risk Rating) (Detail) (USD $) In Millions, unless otherwise specified	Jan. 26, 2013	Jul. 28, 2012	Jan. 28, 2012
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	$ 8,092	$ 7,626
Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	3,444	3,179	3,049
Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	1,785	1,796	1,673
Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	2,863	2,651	2,666
Rating One To Four [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	4,068	3,915
Rating One To Four [Member] | Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	1,607	1,532
Rating One To Four [Member] | Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	882	831
Rating One To Four [Member] | Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	1,579	1,552
Rating Five To Six [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	3,541	3,293
Rating Five To Six [Member] | Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	1,505	1,342
Rating Five To Six [Member] | Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	857	921
Rating Five To Six [Member] | Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	1,179	1,030
Rating Seven And Higher [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	209	144
Rating Seven And Higher [Member] | Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	58	31
Rating Seven And Higher [Member] | Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	46	44
Rating Seven And Higher [Member] | Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	105	69
Total Internal Credit Risk Rating [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	7,818	7,352
Total Internal Credit Risk Rating [Member] | Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	3,170	2,905
Total Internal Credit Risk Rating [Member] | Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	1,785	1,796
Total Internal Credit Risk Rating [Member] | Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Minimum Payments to be Received	2,863	2,651
Residual Value [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Unguaranteed Residual Values of Leased Property	274	274
Residual Value [Member] | Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Unguaranteed Residual Values of Leased Property	274	274
Residual Value [Member] | Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Unguaranteed Residual Values of Leased Property	0	0
Residual Value [Member] | Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases, Unguaranteed Residual Values of Leased Property	0	0
Internal Credit Risk Rating [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	8,092	7,626
Internal Credit Risk Rating [Member] | Lease Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	3,444	3,179
Internal Credit Risk Rating [Member] | Loan Receivables [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	1,785	1,796
Internal Credit Risk Rating [Member] | Financed Service Contracts And Other [Member]
Financing Receivables And Guarantees [Line Items]
Capital Leases, Net Investment in Direct Financing Leases	$ 2,863	$ 2,651