Financing Receivables - Summary of Allowances for Credit Loss and Related Financing Receivables (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 26, 2019	Oct. 27, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	$ 126	$ 205
Provisions (benefits)	24	(5)
Recoveries (write-offs), net	(16)
Foreign exchange and other	(1)	(1)
Allowance for credit loss as of end of period	133	199
Lease Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	46	135
Provisions (benefits)	(3)	(3)
Recoveries (write-offs), net	0
Foreign exchange and other	0	(1)
Allowance for credit loss as of end of period	43	131
Loan Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	71	60
Provisions (benefits)	27	0
Recoveries (write-offs), net	(16)
Foreign exchange and other	(1)	0
Allowance for credit loss as of end of period	81	60
Financed Service Contracts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss as of beginning of period	9	10
Provisions (benefits)	0	(2)
Recoveries (write-offs), net	0
Foreign exchange and other	0	0
Allowance for credit loss as of end of period	$ 9	$ 8