Description of alternative method used to amortize gain (loss) for defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (o)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_DefinedBenefitPlanAlternativeMethodUsedToAmortizeNetGainsAndLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contributions received and expected to be received by defined benefit plan from employer in current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480482/715-20-55-18

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-6

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

+ Details

Name:	us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsAccumulatedBenefitObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480794/715-70-50-1

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Defined benefit plan diversifications.

+ References

No definition available.

+ Details

Name:	wat_DefinedBenefitPlanDiversifications
Namespace Prefix:	wat_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The effect of a one-quarter-percentage-point increase in the assumed discount rate on the net periodic benefit cost. (For purposes of this disclosure, all other assumptions shall be held constant, and the effects shall be measured based on the substantive plan that is the basis for the accounting.)

+ References

No definition available.

+ Details

Name:	wat_DefinedBenefitPlanEffectOfOneQuarterPercentagePointIncreaseInDiscountRateOnNetPeriodicBenefitCost
Namespace Prefix:	wat_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Vesting percentage of employee's contributions to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	wat_DefinedContributionPlanEmployeeContributionAnnualVestingPercentage
Namespace Prefix:	wat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the cost recognized during the period for non-U.S. retirement plans not in the scope of US GAAP.

+ References

No definition available.

+ Details

Name:	wat_RetirementPlansCompanyContributionsToOtherNonUSRetirementPlans
Namespace Prefix:	wat_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=wat_UsRetireeHealthcarePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanNameAxis=wat_UsDefinedContributionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Retirement Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Company contributions to defined contribution plans	amortize cumulative actuarial gains and losses in excess of 10% of the larger of the market-related value of plan assets and the projected benefit obligation over the expected future service of active participants.
Company contributions made to other non U S post-retirement plans	$ 18	$ 18	$ 16
Effect of one-quarter percentage point increase in discount rate on net periodic benefit cost	less than $1 million
US Retiree Healthcare Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan diversification	investments are diversified among market capitalization and investment strategy, and targets a 45% allocation of the equity portfolio to be invested in financial markets outside of the United States.
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	$ 74	81
US Defined Contribution Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee 401(k) contributions as % of salary, upper range limit	60.00%
Company 401(k) matching contribution rate as % of employee contribution	100.00%
Company 401(k) matching contribution limit as % of salary	6.00%
Annual vesting percentage on employee 401(k) contributions	100.00%
Company contributions to defined contribution plans	$ 20	$ 22	$ 21
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in current fiscal year	3
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in current fiscal year	$ 6