1.0.0.3 false Out-of-Period Adjustments false 1 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 2 Out-of-Period Adjustments [Abstract] 0 wat_OutOfPeriodAdjustmentsAbstract wat false na duration string Out-of-Period Adjustments [Abstract] false false false false false true false false false 1 false false 0 0 false false Out-of-Period Adjustments [Abstract] false 3 Out-of-Period Adjustments 1 us-gaap_AccountingChangesAndErrorCorrectionsTextBlock us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 <div><div><a name="_AUCa17d72d0f7594964809506d59a077767">3  Out-of-Period Adjustments</a>   During 2008, the Company identified errors originating in periods prior to the three months ended June 28, 2008. The errors primarily related to (i) an overstatement of the Company’s income tax expense of $16 million as a result of errors in recording its income tax provision during the period from 2000 to March 29, 2008 and (ii) an understatement of amortization expense of $9 million for certain capitalized software. The Company incorrectly calculated its provision for income taxes by tax-effecting its tax liability utilizing a U.S. tax rate of 35% instead of an Irish tax rate of approximately 10%. In addition, the Company incorrectly accounted for Irish-based capitalized software and the related amortization expense as U.S. Dollar-denominated instead of Euro-denominated, resulting in an understatement of amortization expense and cumulative translation adjustment.   The Company identified and corrected the errors in the three months ended June 28, 2008, which had the effect of increasing cost of sales by $9 million; reducing gross profit and income from operations before income tax by $9 million; reducing the provision for income taxes by $16 million and increasing net income by $8 million. For the year ended December 31, 2008, the errors had the effect of reducing the Company’s effective tax rate by 4.0 percentage points. In addition, the out-of-period adjustments had the following effect on the consolidated balance sheet as of June 28, 2008: increased the gross carrying value of capitalized software by $46 million; increased accumulated amortization for capitalized software by $36 million; reduced deferred tax liabilities by $14 million and increased accumulated other comprehensive income by $17 million.   The Company did not believe that the prior period errors, individually or in the aggregate, were material to any previously issued annual or quarterly financial statements. In addition, the Company did not believe that the adjustments described above to correct the cumulative effect of the errors in the three months ended June 28, 2008 were material to the three months ended June 28, 2008 or to the full year results for 2008. As a result, the Company did not restate its previously issued annual financial statements or interim financial data.</div></div> 3  Out-of-Period Adjustments   During 2008, the Company identified errors originating in periods prior to the three months ended June 28, 2008. The false false No definition available. No authoritative reference available. false false 1 2 false UnKnown UnKnown UnKnown false true