Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Financing Receivables
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of fiscal year	$ 295	$ 375	$ 382
Provisions (benefits)	(89)	(35)	17
Recoveries (write-offs), net	(6)	(49)	(15)
Foreign exchange and other	5	4	(9)
Balance at end of fiscal year	205	295	375
Accounts Receivable
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of fiscal year	211	249	302
Provisions (benefits)	(45)	27	(26)
Recoveries (write-offs), net	(37)	(61)	(28)
Foreign exchange and other	0	(4)	1
Balance at end of fiscal year	$ 129	$ 211	$ 249