| **Fair Value Measurements (Tables)**                          | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
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| **Fair Value Disclosures [Abstract]**                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| Fair Value Assets And Liabilities Measured On Recurring Basis |    Fair Value Measurements at Reporting Date Using      Quoted Prices inActive Markets for IdenticalFinancialInstruments SignificantOtherObservableInputs SignificantUnobservableInputs   As of March 31, 2016 (Level 1) (Level 2) (Level 3) Balance Sheet ClassificationAssets         Bank and time deposits$345 $345 $— $— Cash equivalentsMoney market funds143 143 — — Cash equivalentsAvailable-for-sale securities:         Corporate bonds623 — 623 — Short-term investments and cash equivalentsU.S. Treasury securities407 407 — — Short-term investments and cash equivalentsU.S. agency securities170 — 170 — Short-term investments and cash equivalentsCommercial paper81 — 81 — Short-term investments and cash equivalentsForeign government securities122 — 122 — Short-term investments and cash equivalentsForeign currency derivatives16 — 16 — Other current assets and other assetsDeferred compensation plan assets (a)8 8 — — Other assetsTotal assets at fair value$1,915 $903 $1,012 $—  Liabilities         Foreign currency derivatives10 — 10 — Accrued and other current liabilities and other liabilitiesDeferred compensation plan liabilities (a)9 9 — — Other liabilitiesTotal liabilities at fair value$19 $9 $10 $—     Fair Value Measurements at Reporting Date Using      Quoted Prices inActive Markets for IdenticalFinancialInstruments SignificantOtherObservableInputs SignificantUnobservableInputs   As ofSeptember 30, 2016 (Level 1) (Level 2) (Level 3) Balance Sheet ClassificationAssets         Bank and time deposits$236 $236 $— $— Cash equivalentsMoney market funds185 185 — — Cash equivalentsAvailable-for-sale securities:         Corporate bonds739 — 739 — Short-term investmentsU.S. Treasury securities379 379 — — Short-term investmentsU.S. agency securities163 — 163 — Short-term investments and cash equivalentsCommercial paper110 — 110 — Short-term investments and cash equivalentsForeign government securities115 — 115 — Short-term investmentsAsset-backed securities54 — 54 — Short-term investmentsForeign currency derivatives33 — 33 — Other current assets and other assetsDeferred compensation plan assets (a)9 9 — — Other assetsTotal assets at fair value$2,023 $809 $1,214 $—  Liabilities         Foreign currency derivatives11 — 11 — Accrued and other current liabilities and other liabilitiesDeferred compensation plan liabilities (a)10 10 — — Other liabilitiesTotal liabilities at fair value$21 $10 $11 $—   |

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| - Definition
Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19190-110258Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258
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| - References
No definition available.
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