Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 27, 2019	Jul. 28, 2018	Jul. 29, 2017
Financing Receivables
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of fiscal year	$ 205	$ 295	$ 375
Provisions (benefits)	(16)	(89)	(35)
Recoveries (write-offs), net	(42)	(6)	(49)
Foreign exchange and other	(21)	5	4
Balance at end of fiscal year	126	205	295
Accounts Receivable
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of fiscal year	129	211	249
Provisions (benefits)	56	(45)	27
Recoveries (write-offs), net	(50)	(37)	(61)
Foreign exchange and other	1	0	(4)
Balance at end of fiscal year	$ 136	$ 129	$ 211