Fair Value Measurements (Details 1) - USD ($) $ in Millions	Oct. 31, 2015	Jul. 31, 2015
Cash and cash equivalents
Cash equivalents:
Total cash equivalents	$ 474	$ 808
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement
Cash equivalents:
Total cash equivalents	262	695
Available-for-sale securities:
Total available-for-sale securities	190	1,079
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement | Cash and cash equivalents
Cash equivalents:
Total cash equivalents	90	533
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement | Cash equivalents in funds held for customers
Cash equivalents:
Total cash equivalents	172	162
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement | Available For Sale Debt Securities In Investments
Available-for-sale securities:
Total available-for-sale securities	0	889
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement | Available For Sale Debt Securities In Funds Held For Customers
Available-for-sale securities:
Total available-for-sale securities	175	175
Fair Value, Measurements, Recurring | Estimate of Fair Value Measurement | Available For Sale Debt Securities In long term investments
Available-for-sale securities:
Total available-for-sale securities	15	15
Fair Value, Measurements, Recurring | Level 1
Cash equivalents:
Total cash equivalents	262	695
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Cash and cash equivalents
Cash equivalents:
Total cash equivalents	90	533
Fair Value, Measurements, Recurring | Level 1 | Cash equivalents in funds held for customers
Cash equivalents:
Total cash equivalents	172	162
Fair Value, Measurements, Recurring | Level 1 | Available For Sale Debt Securities In Investments
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Available For Sale Debt Securities In Funds Held For Customers
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Available For Sale Debt Securities In long term investments
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 2
Cash equivalents:
Total cash equivalents	0	0
Available-for-sale securities:
Total available-for-sale securities	175	1,064
Fair Value, Measurements, Recurring | Level 2 | Cash and cash equivalents
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | Cash equivalents in funds held for customers
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | Available For Sale Debt Securities In Investments
Available-for-sale securities:
Total available-for-sale securities	0	889
Fair Value, Measurements, Recurring | Level 2 | Available For Sale Debt Securities In Funds Held For Customers
Available-for-sale securities:
Total available-for-sale securities	175	175
Fair Value, Measurements, Recurring | Level 2 | Available For Sale Debt Securities In long term investments
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 3
Cash equivalents:
Total cash equivalents	0	0
Available-for-sale securities:
Total available-for-sale securities	15	15
Fair Value, Measurements, Recurring | Level 3 | Cash and cash equivalents
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | Cash equivalents in funds held for customers
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | Available For Sale Debt Securities In Investments
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Available For Sale Debt Securities In Funds Held For Customers
Available-for-sale securities:
Total available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Available For Sale Debt Securities In long term investments
Available-for-sale securities:
Total available-for-sale securities	$ 15	$ 15