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		6 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Accounting Policies [Abstract]
Net income	$ 189	$ 183	$ 223	$ 181
Shares used in basic per share amounts:
Weighted average common shares outstanding (in shares)	260	256	260	256
Shares used in diluted per share amounts:
Weighted average common shares outstanding (in shares)	260	256	260	256
Dilutive common equivalent shares from stock options and restricted stock awards (in shares)	4	4	4	4
Dilutive weighted average common shares outstanding (in shares)	264	260	264	260
Basic and diluted net income per share:
Basic net income (loss) per share (in dollars per share)	$ 0.73	$ 0.72	$ 0.86	$ 0.71
Diluted net income (loss) per share (in dollars per share)	$ 0.72	$ 0.70	$ 0.84	$ 0.70
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	2	1	2