Financing Receivables - Summary of Allowances for Credit Loss and Related Financing Receivables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	$ 145	$ 200	$ 126	$ 205
Provisions (benefits)	(11)	(1)	27	(5)
Recoveries (write-offs), net	(2)	(26)	(20)	(26)
Foreign exchange and other	(4)	(20)	(5)	(21)
Allowance for credit loss as of end of period	128	153	128	153
Lease Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	42	127	46	135
Provisions (benefits)	(4)	(41)	(8)	(48)
Recoveries (write-offs), net	(1)	2	(2)	2
Foreign exchange and other	(1)	(20)	0	(21)
Allowance for credit loss as of end of period	36	68	36	68
Loan Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	95	64	71	60
Provisions (benefits)	(5)	13	37	17
Recoveries (write-offs), net	(1)	0	(18)	0
Foreign exchange and other	(3)	0	(4)	0
Allowance for credit loss as of end of period	86	77	86	77
Financed Service Contracts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	8	9	9	10
Provisions (benefits)	(2)	27	(2)	26
Recoveries (write-offs), net	0	(28)	0	(28)
Foreign exchange and other	0	0	(1)	0
Allowance for credit loss as of end of period	$ 6	$ 8	$ 6	$ 8