Fair Value Measurements (Details 1) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	Oct. 31, 2011	Jul. 31, 2011
Cash equivalents:
Cash equivalents	$ 333	$ 854
Available-for-sale debt securities:
Investments	947	933
Level 1 [Member]
Cash equivalents:
Cash equivalents	333	854
Available-for-sale debt securities:
Investments	0	0
Level 2 [Member]
Cash equivalents:
Cash equivalents	0	0
Available-for-sale debt securities:
Investments	893	874
Level 3 [Member]
Cash equivalents:
Cash equivalents	0	0
Available-for-sale debt securities:
Investments	54	59
Cash and Cash Equivalents [Member]
Cash equivalents:
Cash equivalents	187	615
Cash and Cash Equivalents [Member] \| Level 1 [Member]
Cash equivalents:
Cash equivalents	187	615
Cash and Cash Equivalents [Member] \| Level 2 [Member]
Cash equivalents:
Cash equivalents	0	0
Cash and Cash Equivalents [Member] \| Level 3 [Member]
Cash equivalents:
Cash equivalents	0	0
Cash equivalents in funds held for customers [Member]
Cash equivalents:
Cash equivalents	146	239
Cash equivalents in funds held for customers [Member] \| Level 1 [Member]
Cash equivalents:
Cash equivalents	146	239
Cash equivalents in funds held for customers [Member] \| Level 2 [Member]
Cash equivalents:
Cash equivalents	0	0
Cash equivalents in funds held for customers [Member] \| Level 3 [Member]
Cash equivalents:
Cash equivalents	0	0
Available For Sale Debt Securities In Investments [Member]
Available-for-sale debt securities:
Investments	718	699
Available For Sale Debt Securities In Investments [Member] \| Level 1 [Member]
Available-for-sale debt securities:
Investments	0	0
Available For Sale Debt Securities In Investments [Member] \| Level 2 [Member]
Available-for-sale debt securities:
Investments	718	699
Available For Sale Debt Securities In Investments [Member] \| Level 3 [Member]
Available-for-sale debt securities:
Investments	0	0
Available For Sale Debt Securities In Funds Held For Customers [Member]
Available-for-sale debt securities:
Investments	175	175
Available For Sale Debt Securities In Funds Held For Customers [Member] \| Level 1 [Member]
Available-for-sale debt securities:
Investments	0	0
Available For Sale Debt Securities In Funds Held For Customers [Member] \| Level 2 [Member]
Available-for-sale debt securities:
Investments	175	175
Available For Sale Debt Securities In Funds Held For Customers [Member] \| Level 3 [Member]
Available-for-sale debt securities:
Investments	0	0
In long term investments [Member]
Available-for-sale debt securities:
Investments	54	59
In long term investments [Member] \| Level 1 [Member]
Available-for-sale debt securities:
Investments	0	0
In long term investments [Member] \| Level 2 [Member]
Available-for-sale debt securities:
Investments	0	0
In long term investments [Member] \| Level 3 [Member]
Available-for-sale debt securities:
Investments	$ 54	$ 59

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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