Selected Quarterly Financial Data (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Apr. 30, 2010	Jan. 31, 2010	Oct. 31, 2009	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Quarterly Financial Information Disclosure [Abstract]
Total net revenue	$ 651	$ 573	$ 1,926	$ 999	$ 575	$ 1,827	$ 857	$ 515	$ 4,151	$ 3,772	$ 3,403
Cost of revenue	191	159	197	205	167	162	175	154
All other costs and expenses	505	472	618	599	492	598	560	455
Operating income (loss) from continuing operations	(45)	(58)	1,111	195	(84)	1,067	122	(94)	1,177	1,037	904
Net income (loss) from continuing operations	(32)	(56)	736	121	(58)	692	80	(64)	767	652	564
Net income (loss) from discontinued operations	36	(1)	(2)	(3)	(6)	(4)	(7)	(6)	25	(18)	10
Net income (loss)	$ 4	$ (57)	$ 734	$ 118	$ (64)	$ 688	$ 73	$ (70)	$ 792	$ 634	$ 574
Basic net income (loss) per share from continuing operations	$ (0.11)	$ (0.19)	$ 2.50	$ 0.41	$ (0.19)	$ 2.28	$ 0.26	$ (0.20)	$ 2.59	$ 2.12	$ 1.79
Basic net income (loss) per share from discontinued operations	$ 0.12	$ 0.00	$ (0.01)	$ (0.01)	$ (0.02)	$ (0.01)	$ (0.02)	$ (0.02)	$ 0.08	$ (0.06)	$ 0.03
Basic net income (loss) per share	$ 0.01	$ (0.19)	$ 2.49	$ 0.40	$ (0.21)	$ 2.27	$ 0.24	$ (0.22)	$ 2.67	$ 2.06	$ 1.82
Diluted net income (loss) per share from continuing operations	$ (0.11)	$ (0.19)	$ 2.43	$ 0.40	$ (0.19)	$ 2.21	$ 0.25	$ (0.20)	$ 2.52	$ 2.06	$ 1.74
Diluted net income (loss) per share from discontinued operations	$ 0.12	$ 0.00	$ (0.01)	$ (0.01)	$ (0.02)	$ (0.01)	$ (0.02)	$ (0.02)	$ 0.08	$ (0.06)	$ 0.03
Diluted net income (loss) per share	$ 0.01	$ (0.19)	$ 2.42	$ 0.39	$ (0.21)	$ 2.20	$ 0.23	$ (0.22)	$ 2.60	$ 2.00	$ 1.77