Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	Jan. 31, 2015	Jul. 31, 2014
Cash and Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	$ 482	$ 849
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Cash equivalents:
Total cash equivalents	359	652
Available-for-sale securities:
Total available-for-sale securities	1,081	1,230
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Estimate of Fair Value Measurement [Member]
Cash equivalents:
Total cash equivalents	180	507
Fair Value, Measurements, Recurring [Member] | Cash equivalents in funds held for customers [Member] | Estimate of Fair Value Measurement [Member]
Cash equivalents:
Total cash equivalents	179	145
Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Investments [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale securities:
Total available-for-sale securities	885	1,065
Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Funds Held For Customers [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale securities:
Total available-for-sale securities	175	144
Fair Value, Measurements, Recurring [Member] | In long term investments [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale securities:
Total available-for-sale securities	21	21
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Cash equivalents:
Total cash equivalents	359	652
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	180	507
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents in funds held for customers [Member]
Cash equivalents:
Total cash equivalents	179	145
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Investments [Member]
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Funds Held For Customers [Member]
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | In long term investments [Member]
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Cash equivalents:
Total cash equivalents	0	0
Available-for-sale securities:
Total available-for-sale securities	1,060	1,209
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents in funds held for customers [Member]
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Investments [Member]
Available-for-sale securities:
Total available-for-sale securities	885	1,065
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Funds Held For Customers [Member]
Available-for-sale securities:
Total available-for-sale securities	175	144
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | In long term investments [Member]
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Cash equivalents:
Total cash equivalents	0	0
Available-for-sale securities:
Total available-for-sale securities	21	21
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member]
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents in funds held for customers [Member]
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Investments [Member]
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Available For Sale Debt Securities In Funds Held For Customers [Member]
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | In long term investments [Member]
Available-for-sale securities:
Total available-for-sale securities	$ 21	$ 21