Cash and Cash Equivalents, Investments and Funds Held for Customers (Details) (USD $) In Millions	Jul. 31, 2011	Jul. 31, 2010
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	$ 1,898	$ 2,050
Available-for-sale securities, amortized cost basis	1,896	2,048
Total cash and cash equivalents, investments and funds held for customers	1,896	2,048
Available-for-sale debt securities:
Other long-term investments	4	4
Total cash and cash equivalents, investments and funds held for customers	1,896	2,048
Cost [Member]
Available-for-sale debt securities:
Total available-for-sale debt securities, amortized cost	931	1,643
Available-for-sale debt securities classified by the stated maturity date of the security
Due within one year, amortized cost	267	432
Due within two years, amortized cost	323	365
Due within three years, amortized cost	190	164
Due after three years, amortized cost	151	682
Total available-for-sale debt securities, amortized cost	931	1,643
Fair Value [Member]
Available-for-sale debt securities classified by the stated maturity date of the security
Due within one year, fair value	267	433
Due within two years, fair value	324	366
Due within three years, fair value	191	164
Due after three years, fair value	151	682
Total available-for-sale debt securities, fair value	933	1,645
Cash and Cash Equivalents [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	722	214
Long-Term Investment [Member]
Classification on balance sheets:
Investments	63	91
Available-for-sale securites, fair value discolusre	63	91
Short-term Investments [Member]
Classification on balance sheets:
Investments	698	1,407
Available-for-sale securites, fair value discolusre	699	1,408
Funds Held For Customers [Member]
Classification on balance sheets:
Available-for-sale securities, amortized cost basis	413	336
Available For Sale Debt Securities In Funds Held For Customers [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	414	337
Cash And Cash Equivalents Including Funds Held For Customers [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	961	401
Municipal bonds [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	434	1,050
Available-for-sale debt securities:
Total available-for-sale debt securities, amortized cost	434	1,049
Available-for-sale debt securities classified by the stated maturity date of the security
Total available-for-sale debt securities, amortized cost	434	1,049
Municipal auction rate securities [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	59	87
Available-for-sale debt securities:
Total available-for-sale debt securities, amortized cost	59	87
Available-for-sale debt securities classified by the stated maturity date of the security
Total available-for-sale debt securities, amortized cost	59	87
Corporate notes [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	288	334
Available-for-sale debt securities:
Total available-for-sale debt securities, amortized cost	287	333
Available-for-sale debt securities classified by the stated maturity date of the security
Total available-for-sale debt securities, amortized cost	287	333
U.S. agency securities [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	152	174
Available-for-sale debt securities:
Total available-for-sale debt securities, amortized cost	151	174
Available-for-sale debt securities classified by the stated maturity date of the security
Total available-for-sale debt securities, amortized cost	151	174
Available-for-Sale Debt Securities [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	933	1,645
Available-for-sale debt securities:
Total available-for-sale debt securities, amortized cost	931	1,643
Available-for-sale debt securities classified by the stated maturity date of the security
Total available-for-sale debt securities, amortized cost	931	1,643
Other Long-term Investments [Member]
Classification on balance sheets:
Available-for-sale securites, fair value discolusre	$ 4	$ 4