Financing Receivables And Guarantees (Allowance For Credit Loss And Related Financing Receivables) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 27, 2012	Oct. 29, 2011	Jul. 28, 2012	Jul. 31, 2010
Lease Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	$ 247			$ 237
Provisions	(2)	2
Foreign exchange and other	3	(6)
Financing Receivable, Allowance for Credit Losses	248	233		237
Loan Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	122			103
Provisions	(10)	5
Foreign exchange and other	2	(5)
Financing Receivable, Allowance for Credit Losses	114	103		103
Capital Leases, Net Investment in Direct Financing Leases	1,816	1,468	1,796
Financed Service Contracts And Other [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	11			27
Provisions	1	2
Foreign exchange and other	0	0
Financing Receivable, Allowance for Credit Losses	12	29		27
Capital Leases, Net Investment in Direct Financing Leases	2,639	2,557	2,651
Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	380			367
Provisions	(11)	9
Foreign exchange and other	5	(11)
Financing Receivable, Allowance for Credit Losses	374	365		367
Capital Leases, Net Investment in Direct Financing Leases	7,795	6,874
Gross Receivables, Net of Unearned Income [Member] | Lease Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Capital Leases, Net Investment in Direct Financing Leases	$ 3,340	$ 2,849	$ 3,179