Description of Business and Summary of Significant Accounting Policies (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Oct. 31, 2015 USD ($) customer $ / shares shares	Oct. 31, 2014 USD ($) customer $ / shares shares
Numerator:
Net loss from continuing operations | $	$ (31)	$ (81)
Net loss from discontinued operations | $	0	(3)
Net loss | $	$ (31)	$ (84)
Shares used in basic per share amounts:
Weighted average common shares outstanding (in shares) | shares	272	286
Shares used in diluted per share amounts:
Weighted average common shares outstanding (in shares) | shares	272	286
Dilutive common equivalent shares from stock options and restricted stock awards (in shares) | shares	0	0
Dilutive weighted average common shares outstanding (in shares) | shares	272	286
Basic and diluted net loss per share:
Basic net income per share from continuing operations (in dollars per share)	$ (0.11)	$ (0.28)
Basic net income per share from discontinued operations (in dollars per share)	0.00	(0.01)
Basic net income per share (in dollars per share)	(0.11)	(0.29)
Diluted net income per share from continuing operations (in dollars per share)	(0.11)	(0.28)
Diluted net income per share from discontinued operations (in dollars per share)	0.00	(0.01)
Diluted net income per share (in dollars per share)	$ (0.11)	$ (0.29)
Shares excluded from computation of diluted net income per share:
Weighted average stock options and restricted stock units that would have been included in the computation of dilutive common equivalent shares outstanding if net income had been reported in the period | shares	12	16
Weighted average stock options and restricted stock units excluded from computation due to anti-dilutive effect | shares	4	2
Customer Concentration Risk | Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk, number of customers | customer	0	0
Customer Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, number of customers | customer	0	0