Description of Business and Summary of Significant Accounting Policies (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
Numerator:
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
Shares used in basic per share amounts:
Weighted average common shares outstanding									296	307	316
Shares used in diluted per share amounts:
Weighted average common shares outstanding									296	307	316
Dilutive common equivalent shares from stock options and restricted stock awards									9	10	9
Dilutive weighted average common shares outstanding									305	317	325
Basic and diluted net income per share:
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
Weighted average stock options and restricted stock units excluded from calculation due to anti-dilutive effect									3	0	8
Description of Business and Summary of Significant Accounting Policies (Textuals)
Average time for amortization of Software									three to five
Advertising expense									151	177	153
Estimated life of property and equipment									two to 30
Finite-Lived Intangible Asset, Useful Life									7 years	7 years
Impairment of intangible assets (excluding goodwill)									0		0
Goodwill, impairment loss									$ 0	$ 24	$ 0
Estimated life of purchased intangible assets									one to nine
Minimum [Member]
Description of Business and Summary of Significant Accounting Policies (Textuals)
Property, plant and equipment, useful life									2 years
Finite-Lived Intangible Asset, Useful Life									1 year
Maximum [Member]
Description of Business and Summary of Significant Accounting Policies (Textuals)
Property, plant and equipment, useful life									30 years
Finite-Lived Intangible Asset, Useful Life									9 years
Accounts Receivable [Member]
Description of Business and Summary of Significant Accounting Policies (Textuals)
Number of customers accounted for more than ten percent of concentration risk									0	0
Sales [Member]
Description of Business and Summary of Significant Accounting Policies (Textuals)
Number of customers accounted for more than ten percent of concentration risk									0	0	0
Software Development [Member] | Minimum [Member]
Description of Business and Summary of Significant Accounting Policies (Textuals)
Property, plant and equipment, useful life									3 years
Software Development [Member] | Maximum [Member]
Description of Business and Summary of Significant Accounting Policies (Textuals)
Property, plant and equipment, useful life									5 years