Financing Receivables - Summary of Allowances for Credit Loss and Related Financing Receivables (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 25, 2020	Jul. 27, 2019	Jul. 28, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss, beginning of period	$ 126	$ 205	$ 295
Provisions (benefits)	38	(16)	(89)
Recoveries (write-offs), net	(22)	(42)	(6)
Foreign exchange and other	(4)	(21)	5
Allowance for credit loss, end of period	138	126	205
Lease Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss, beginning of period	46	135	162
Provisions (benefits)	5	(54)	(26)
Recoveries (write-offs), net	(3)	(14)	(1)
Foreign exchange and other	0	(21)	0
Allowance for credit loss, end of period	48	46	135
Loan Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss, beginning of period	71	60	103
Provisions (benefits)	32	11	(43)
Recoveries (write-offs), net	(19)	0	(5)
Foreign exchange and other	(3)	0	5
Allowance for credit loss, end of period	81	71	60
Financed Service Contracts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss, beginning of period	9	10	30
Provisions (benefits)	1	27	(20)
Recoveries (write-offs), net	0	(28)	0
Foreign exchange and other	(1)	0	0
Allowance for credit loss, end of period	$ 9	$ 9	$ 10