Fair Value Measurements (Details 1) - USD ($) $ in Millions	Oct. 31, 2016	Jul. 31, 2016
Fair Value Asset Measured on Recurring Basis [Line Items]
Long-term debt	$ 500	$ 500
Cash and cash equivalents
Cash equivalents:
Total cash equivalents	360	638
Fair value, measurements, recurring \| Estimate of fair value measurement
Cash equivalents:
Total cash equivalents	0	416
Available-for-sale securities:
Total available-for-sale securities	460	657
Fair value, measurements, recurring \| Estimate of fair value measurement \| Cash and cash equivalents
Cash equivalents:
Total cash equivalents	0	312
Fair value, measurements, recurring \| Estimate of fair value measurement \| Cash equivalents in funds held for customers
Cash equivalents:
Total cash equivalents	0	104
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	245	442
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	200	200
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	0	416
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	0	312
Fair value, measurements, recurring \| Level 1 \| Cash equivalents in funds held for customers
Cash equivalents:
Total cash equivalents	0	104
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	445	642
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	245	442
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	200	200
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

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Fair Value Asset Measured On Recurring Basis.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

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-Publisher FASB
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6505594

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