Cash and Cash Equivalents, Investments and Funds Held for Customers - Classification on Balance Sheets (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2014	Jul. 31, 2014	Oct. 31, 2013	Jul. 31, 2013
Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents, Amortized Cost	$ 542	$ 849	$ 417	$ 1,009
Investments and funds, Fair Value	1,978	2,234
Total cash and cash equivalents, investments, and funds held for customers, Amortized Cost	1,977	2,233
Total cash and cash equivalents, investments, and funds held for customers, Fair Value	1,978	2,234
Cash and Cash Equivalents [Member]
Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents, Amortized Cost	542	849
Cash and Cash Equivalents, Fair Value Disclosure	542	849
Investments [Member]
Cash and Cash Equivalents Items [Line Items]
Investments and funds, Amortized Cost	1,046	1,064
Investments and funds, Fair Value	1,047	1,065
Funds held for customers [Member]
Cash and Cash Equivalents Items [Line Items]
Investments and funds, Amortized Cost	358	289
Investments and funds, Fair Value	358	289
Long-term investments [Member]
Cash and Cash Equivalents Items [Line Items]
Investments and funds, Amortized Cost	31	31
Investments and funds, Fair Value	$ 31	$ 31