Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	Apr. 30, 2013	Jul. 31, 2012
Fair Value, Measurements, Recurring \| Estimate of Fair Value, Fair Value Disclosure [Member]
Cash equivalents:
Cash equivalents	$ 1,198	$ 333
Investments	829	600
Fair Value, Measurements, Recurring \| Level 1
Cash equivalents:
Cash equivalents	1,198	333
Investments	38	33
Fair Value, Measurements, Recurring \| Level 2
Cash equivalents:
Cash equivalents	0	0
Investments	758	526
Fair Value, Measurements, Recurring \| Level 3
Cash equivalents:
Cash equivalents	0	0
Investments	33	41
Cash equivalents in cash and cash equivalents
Cash equivalents:
Cash equivalents	1,412	393
Cash equivalents in cash and cash equivalents \| Fair Value, Measurements, Recurring \| Estimate of Fair Value, Fair Value Disclosure [Member]
Cash equivalents:
Cash equivalents	1,189	219
Cash equivalents in cash and cash equivalents \| Fair Value, Measurements, Recurring \| Level 1
Cash equivalents:
Cash equivalents	1,189	219
Cash equivalents in cash and cash equivalents \| Fair Value, Measurements, Recurring \| Level 2
Cash equivalents:
Cash equivalents	0	0
Cash equivalents in cash and cash equivalents \| Fair Value, Measurements, Recurring \| Level 3
Cash equivalents:
Cash equivalents	0	0
Cash equivalents in funds held for customers \| Fair Value, Measurements, Recurring \| Estimate of Fair Value, Fair Value Disclosure [Member]
Cash equivalents:
Cash equivalents	9	114
Cash equivalents in funds held for customers \| Fair Value, Measurements, Recurring \| Level 1
Cash equivalents:
Cash equivalents	9	114
Cash equivalents in funds held for customers \| Fair Value, Measurements, Recurring \| Level 2
Cash equivalents:
Cash equivalents	0	0
Cash equivalents in funds held for customers \| Fair Value, Measurements, Recurring \| Level 3
Cash equivalents:
Cash equivalents	0	0
Available For Sale Securities In Investments \| Fair Value, Measurements, Recurring \| Estimate of Fair Value, Fair Value Disclosure [Member]
Cash equivalents:
Investments	583	351
Available For Sale Securities In Investments \| Fair Value, Measurements, Recurring \| Level 1
Cash equivalents:
Investments	0	0
Available For Sale Securities In Investments \| Fair Value, Measurements, Recurring \| Level 2
Cash equivalents:
Investments	583	351
Available For Sale Securities In Investments \| Fair Value, Measurements, Recurring \| Level 3
Cash equivalents:
Investments	0	0
Available For Sale Securities In Funds Held For Customers \| Fair Value, Measurements, Recurring \| Estimate of Fair Value, Fair Value Disclosure [Member]
Cash equivalents:
Investments	175	175
Available For Sale Securities In Funds Held For Customers \| Fair Value, Measurements, Recurring \| Level 1
Cash equivalents:
Investments	0	0
Available For Sale Securities In Funds Held For Customers \| Fair Value, Measurements, Recurring \| Level 2
Cash equivalents:
Investments	175	175
Available For Sale Securities In Funds Held For Customers \| Fair Value, Measurements, Recurring \| Level 3
Cash equivalents:
Investments	0	0
Available For Sale Securities In long term investments \| Fair Value, Measurements, Recurring \| Estimate of Fair Value, Fair Value Disclosure [Member]
Cash equivalents:
Investments	71	74
Available For Sale Securities In long term investments \| Fair Value, Measurements, Recurring \| Level 1
Cash equivalents:
Investments	38	33
Available For Sale Securities In long term investments \| Fair Value, Measurements, Recurring \| Level 2
Cash equivalents:
Investments	0	0
Available For Sale Securities In long term investments \| Fair Value, Measurements, Recurring \| Level 3
Cash equivalents:
Investments	$ 33	$ 41

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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