Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jan. 26, 2019	Jul. 28, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 135	$ 129
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	20,000,000,000	20,000,000,000
Common stock, shares issued (in shares)	4,424,000,000	4,614,000,000
Common stock, shares outstanding (in shares)	4,424,000,000	4,614,000,000