2.2.0.7 true Acquisitions (Details) (Thar Instruments [Member], USD $) 40300 - Disclosure - Acquisitions (Details) true false In Millions false false 1 true false false false Thar Instruments [Member] us-gaap_BusinessAcquisitionAxis xbrldi http://xbrl.org/2006/xbrldi wat_TharInstrumentsMember us-gaap_BusinessAcquisitionAxis explicitMember false 2 USD true false false false Thar Instruments [Member] us-gaap_BusinessAcquisitionAxis xbrldi http://xbrl.org/2006/xbrldi wat_TharInstrumentsMember us-gaap_BusinessAcquisitionAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 2 Cost of Acquired Entity [Abstract] 2 us-gaap_BusinessAcquisitionCostOfAcquiredEntityAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 3 Cash paid for acquired entity 2 us-gaap_BusinessAcquisitionCostOfAcquiredEntityCashPaid us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 true true false false 36000000 36 false false false xbrli:monetaryItemType monetary Amount of cash paid to acquire the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 68 -Subparagraph f(1) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph d false 4 Debt assumed from business acquisition 2 us-gaap_BusinessAcquisitionPurchasePriceAllocationNoncurrentLiabilitiesLongTermDebt us-gaap true credit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 true true false false 4000000 4 false false false xbrli:monetaryItemType monetary The amount of acquisition cost of a business combination allocated to the noncurrent portion of the long-term debt assumed from the acquired entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph e Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 37 -Subparagraph g Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 98-1 false 5 Pro forma effect of business acquisition 2 us-gaap_BusinessAcquisitionProFormaInformationTextBlock us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 <p style='margin-top:0pt; margin-bottom:0pt'><font style="font-family:Times New Roman;font-size:10pt;margin-left:0px;">The pro forma effect of the results of the ongoing operations for the Company and Thar as though the acquisition of Thar had occurred at the beginning of the periods covered by this report is immaterial.</font></p> false false false 2 false false false false 0 0 false false false us-types:textBlockItemType textblock Pro Forma results of operations for a material business acquisition or series of individually immaterial business acquisitions that are material in the aggregate. This element may be used as a single block of text to encapsulate all disclosures regarding the pro forma results of the combined entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 68 -Subparagraph r(2, 3) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 54 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 55 false 2 4 false Millions UnKnown UnKnown false true