Description of Business and Summary of Significant Accounting Policies - Schedule of Composition of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Accounting Policies [Abstract]
Net income	$ 1,378	$ 1,186	$ 1,601	$ 1,367
Shares used in basic per share amounts:
Weighted average common shares outstanding (in shares)	260	257	260	256
Shares used in diluted per share amounts:
Weighted average common shares outstanding (in shares)	260	257	260	256
Dilutive common equivalent shares from stock options and restricted stock awards (in shares)	4	5	4	4
Dilutive weighted average common shares outstanding (in shares)	264	262	264	260
Basic and diluted net income per share:
Basic net income per share (in dollars per share)	$ 5.30	$ 4.62	$ 6.16	$ 5.34
Diluted net income per share (in dollars per share)	$ 5.22	$ 4.53	$ 6.06	$ 5.25
Shares excluded from diluted net income per share:
Weighted average stock options and restricted stock units that have been excluded from dilutive common equivalent shares outstanding due to their anti-dilutive effect (in shares)	1	0	1	2