Financing Receivables - Summary of Allowances for Credit Loss and Related Financing Receivables (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 25, 2020	Jan. 26, 2019	Jan. 25, 2020	Jan. 26, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	$ 133	$ 199	$ 126	$ 205
Provisions (benefits)	14	1	38	(4)
Recoveries (write-offs), net	(2)		(18)
Foreign exchange and other	0		(1)	(1)
Allowance for credit loss as of end of period	145	200	145	200
Lease Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	43	131	46	135
Provisions (benefits)	(1)	(4)	(4)	(7)
Recoveries (write-offs), net	(1)		(1)
Foreign exchange and other	1		1	(1)
Allowance for credit loss as of end of period	42	127	42	127
Loan Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	81	60	71	60
Provisions (benefits)	15	4	42	4
Recoveries (write-offs), net	(1)		(17)
Foreign exchange and other	0		(1)	0
Allowance for credit loss as of end of period	95	64	95	64
Financed Service Contracts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	9	8	9	10
Provisions (benefits)	0	1	0	(1)
Recoveries (write-offs), net	0		0
Foreign exchange and other	(1)		(1)	0
Allowance for credit loss as of end of period	$ 8	$ 9	$ 8	$ 9