Name:	dgx_FundsinatrustpertainingtoallparticipantdeferralsandcompanymatchingamountsrelatedtotheSDCP
Namespace Prefix:	dgx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

SDCP II graded vesting percentage

No definition available.

Name:	dgx_SdcpIiGradedVestingPercentage
Namespace Prefix:	dgx_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of salary deferral under the Supplemental Deferred Compensation Plan. This plans is an unfunded, non-qualified plan that provides for certain management and highly compensated employees to defer up to this percentage of their annual salary in excess of their defined contribution plan limits.

No definition available.

Name:	dgx_SupplementalDeferredCompensationPlanSalaryDeferral
Namespace Prefix:	dgx_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

Deferral percentage of the variable incentive compensation under the Supplemental Deferred Compensation Plan. The plan is an unfunded, non-qualified plan that provides for certain management and highly compensated eligible employees to defer up to this percentage of their variable incentive compensation.

No definition available.

Name:	dgx_SupplementalDeferredCompensationPlanVariableIncentiveCompensationDeferral
Namespace Prefix:	dgx_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

No definition available.

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

Amount of contributions made by employer into fund established for purposes of making future disbursement to individual in accordance with deferred compensation arrangement.

No definition available.

Name:	us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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.

No definition available.

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

The carrying amount of the liability as of the balance sheet date to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 710
-SubTopic 10
-Name Accounting Standards Codification
-Section 30
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483043/710-10-30-1

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

Minimum period the individual is required to perform services to be fully vested under the deferred compensation arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 710
-SubTopic 10
-Section 55
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482943/710-10-55-7

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Name:	us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

No definition available.