Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (37)	$ 71	$ (48)	$ 52
Other comprehensive income (loss), net of income taxes:
Unrealized gains on available-for-sale debt securities	0	0	2	0
Unrealized gains on available-for-sale equity securities	(3)	0	(4)	3
Foreign currency translation gains (losses)	(6)	0	(8)	1
Total other comprehensive income (loss), net	(9)	0	(10)	4
Comprehensive income (loss)	$ (46)	$ 71	$ (58)	$ 56