Description of Business and Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Numerator:
Net income	$ 1,200	$ 964	$ 1,162	$ 947
Shares used in basic per share amounts:
Weighted average common shares outstanding (in shares)	257	256	256	257
Shares used in diluted per share amounts:
Weighted average common shares outstanding (in shares)	257	256	256	257
Dilutive common equivalent shares from stock options and restricted stock awards (in shares)	5	4	4	4
Dilutive weighted average common shares outstanding (in shares)	262	260	260	261
Basic and diluted net income per share:
Basic net income per share (in dollars per share)	$ 4.68	$ 3.76	$ 4.54	$ 3.68
Diluted net income per share (in dollars per share)	$ 4.59	$ 3.70	$ 4.47	$ 3.63
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)	0	3	2	4