Description of Business and Summary of Significant Accounting Policies - Schedule of Impact of ASU 2016-18 and ASU 2014-09 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating activities	$ (143)	$ (78)
Investing activities	20	(128)
Financing activities	(182)	158
Effect of exchange rates on cash, cash equivalents, restricted cash, and restricted cash equivalents	(4)	(5)
Net decrease in cash, cash equivalents, restricted cash, and restricted cash equivalents	(309)	(53)
Prepaid expenses and other current assets	269		$ 202
Long-term deferred income taxes			2
Other assets			213
Deferred revenue	513		581
Other current liabilities	202		198
Long-term deferred revenue	2		3
Other long-term obligations			184
Stockholders’ equity	2,782	1,562	2,816	$ 1,699
Net revenue	1,016	910
Selling and marketing	346	308
Operating loss	(10)	(35)
Income tax provision (benefit)	$ (48)	(35)
Net loss		$ (2)
Diluted net loss per share (in dollars per share)	$ 0.13	$ (0.01)
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating activities		$ (78)
Investing activities		(75)
Financing activities		158
Effect of exchange rates on cash, cash equivalents, restricted cash, and restricted cash equivalents		(5)
Net decrease in cash, cash equivalents, restricted cash, and restricted cash equivalents		0
Prepaid expenses and other current assets			184
Long-term deferred income taxes			87
Other assets			190
Deferred revenue			961
Other current liabilities			191
Long-term deferred revenue			197
Other long-term obligations			123
Stockholders’ equity			2,354
Net revenue		886
Selling and marketing		308
Operating loss		(57)
Income tax provision (benefit)		(42)
Net loss		$ (17)
Diluted net loss per share (in dollars per share)		$ (0.07)
Restatement Adjustment | Accounting Standards Update 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating activities		$ 0
Investing activities		(53)
Financing activities		0
Effect of exchange rates on cash, cash equivalents, restricted cash, and restricted cash equivalents		0
Net decrease in cash, cash equivalents, restricted cash, and restricted cash equivalents		(53)
Restatement Adjustment | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets			18
Long-term deferred income taxes			(85)
Other assets			23
Deferred revenue			(380)
Other current liabilities			7
Long-term deferred revenue			(194)
Other long-term obligations			61
Stockholders’ equity			$ 462
Net revenue		24
Selling and marketing		0
Operating loss		22
Income tax provision (benefit)		7
Net loss		$ 15
Diluted net loss per share (in dollars per share)		$ 0.06