Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jan. 31, 2014 Level 3	Jan. 31, 2014 Fair Value, Measurements, Recurring Total Fair Value	Jul. 31, 2013 Fair Value, Measurements, Recurring Total Fair Value	Jan. 31, 2014 Fair Value, Measurements, Recurring Level 1	Jul. 31, 2013 Fair Value, Measurements, Recurring Level 1	Jan. 31, 2014 Fair Value, Measurements, Recurring Level 2	Jul. 31, 2013 Fair Value, Measurements, Recurring Level 2	Jan. 31, 2014 Fair Value, Measurements, Recurring Level 3	Jul. 31, 2013 Fair Value, Measurements, Recurring Level 3	Jan. 31, 2014 Cash and Cash Equivalents [Member]	Jul. 31, 2013 Cash and Cash Equivalents [Member]	Jan. 31, 2014 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Total Fair Value	Jul. 31, 2013 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Total Fair Value	Jan. 31, 2014 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Level 1	Jul. 31, 2013 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Level 1	Jan. 31, 2014 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Level 2	Jul. 31, 2013 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Level 2	Jan. 31, 2014 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Level 3	Jul. 31, 2013 Cash and Cash Equivalents [Member] Fair Value, Measurements, Recurring Level 3	Jan. 31, 2014 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Total Fair Value	Jul. 31, 2013 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Total Fair Value	Jan. 31, 2014 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Level 1	Jul. 31, 2013 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Level 1	Jan. 31, 2014 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Level 2	Jul. 31, 2013 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Level 2	Jan. 31, 2014 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Level 3	Jul. 31, 2013 Cash equivalents In funds held for customers Fair Value, Measurements, Recurring Level 3	Jan. 31, 2014 Available-for-sale securities In investments Fair Value, Measurements, Recurring Total Fair Value	Jul. 31, 2013 Available-for-sale securities In investments Fair Value, Measurements, Recurring Total Fair Value	Jan. 31, 2014 Available-for-sale securities In investments Fair Value, Measurements, Recurring Level 1	Jul. 31, 2013 Available-for-sale securities In investments Fair Value, Measurements, Recurring Level 1	Jan. 31, 2014 Available-for-sale securities In investments Fair Value, Measurements, Recurring Level 2	Jul. 31, 2013 Available-for-sale securities In investments Fair Value, Measurements, Recurring Level 2	Jan. 31, 2014 Available-for-sale securities In investments Fair Value, Measurements, Recurring Level 3	Jul. 31, 2013 Available-for-sale securities In investments Fair Value, Measurements, Recurring Level 3	Jan. 31, 2014 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Total Fair Value	Jul. 31, 2013 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Total Fair Value	Jan. 31, 2014 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Level 1	Jul. 31, 2013 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Level 1	Jan. 31, 2014 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Level 2	Jul. 31, 2013 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Level 2	Jan. 31, 2014 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Level 3	Jul. 31, 2013 Available-for-sale securities In funds held for customers Fair Value, Measurements, Recurring Level 3	Jan. 31, 2014 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Total Fair Value	Jul. 31, 2013 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Total Fair Value	Jan. 31, 2014 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Level 1	Jul. 31, 2013 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Level 1	Jan. 31, 2014 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Level 2	Jul. 31, 2013 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Level 2	Jan. 31, 2014 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Level 3	Jul. 31, 2013 Available-for-sale securities In long-term investments Fair Value, Measurements, Recurring Level 3
Cash equivalents:
Cash equivalents		$ 402	$ 917	$ 402	$ 917	$ 0	$ 0	$ 0	$ 0	$ 625	$ 1,009	$ 287	$ 857	$ 287	$ 857	$ 0	$ 0	$ 0	$ 0	$ 115	$ 60	$ 115	$ 60	$ 0	$ 0	$ 0	$ 0
Available-for-sale securities		$ 909	$ 893	$ 28	$ 33	$ 853	$ 827	$ 28	$ 33																			$ 706	$ 652	$ 28	$ 0	$ 678	$ 652	$ 0	$ 0	$ 175	$ 175	$ 0	$ 0	$ 175	$ 175	$ 0	$ 0	$ 28	$ 66	$ 0	$ 33	$ 0	$ 0	$ 28	$ 33
Number of auction rate securities redeemed	5
Number of auction rate securities still outstanding	28