Cash and Cash Equivalents, Investments and Funds Held for Customers - Classified by the stated maturity date (Details) (USD $) In Millions, unless otherwise specified	Jan. 31, 2015	Jul. 31, 2014
Available-for-sale Securities, Debt Maturities
Due within one year, Amortized Cost	$ 364	$ 363
Due within one year, Fair Value	365	363
Due within two years, Amortized Cost	408	443
Due within two years, Fair Value	408	443
Due within three years, Amortized Cost	261	303
Due within three years, Fair Value	261	303
Due after three years, Amortized Cost	47	120
Due after three years, Fair Value	47	121
Total available-for-sale debt securities, Amortized Cost	1,080	1,229
Total available-for-sale debt securities, Fair Value	$ 1,081	$ 1,230