Percentage of Net Accounts Receivable

No definition available.

Name:	dgx_PercentageofNetAccountsReceivable
Namespace Prefix:	dgx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of Net Revenues

+ References

No definition available.

+ Details

Name:	dgx_PercentageofNetRevenues
Namespace Prefix:	dgx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of Billing Fully Reserve

+ References

No definition available.

+ Details

Name:	dgx_PeriodofBillingFullyReserve
Namespace Prefix:	dgx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Revenue, Collection of Consideration Period

+ References

No definition available.

+ Details

Name:	dgx_RevenueCollectionofConsiderationPeriod
Namespace Prefix:	dgx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of allowance for credit loss on accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

+ Details

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

- Definition

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

+ References

+ Details

Name:	us-gaap_ProvisionForDoubtfulAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsegmentsAxis=dgx_HealthcareInsurersMember
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:

- Details

Name:	us-gaap_SubsegmentsAxis=dgx_GovernmentPayersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsegmentsAxis=dgx_ClientPayersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsegmentsAxis=dgx_PatientMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsegmentsAxis=dgx_DSBusinessesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=dgx_DiagnosticInformationServicesBusinessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=dgx_FeeforserviceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=dgx_CapitatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_AllOtherSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

REVENUE RECOGNITION (Details) - USD ($) $ in Millions	12 Months Ended
REVENUE RECOGNITION (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Percentage of net revenues	100.00%	100.00%	100.00%
Percentage of net accounts receivable	100.00%	100.00%
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 28	$ 15
Write-offs of accounts receivable, net of recoveries	(1)	(6)
Ending balance	31	28	$ 15
Provision for credit losses	$ 4	$ 19	$ 11
Healthcare insurers: \| Minimum
Segment Reporting Information [Line Items]
Collection of consideration	30 days
Healthcare insurers: \| Maximum
Segment Reporting Information [Line Items]
Collection of consideration	60 days
Government payers
Segment Reporting Information [Line Items]
Collection of consideration	30 days
Client payers \| Minimum
Segment Reporting Information [Line Items]
Collection of consideration	60 days
Client payers \| Maximum
Segment Reporting Information [Line Items]
Collection of consideration	90 days
Patients \| Minimum
Segment Reporting Information [Line Items]
Collection of consideration	30 days
Patients \| Maximum
Segment Reporting Information [Line Items]
Collection of consideration	60 days
DS \| Minimum
Segment Reporting Information [Line Items]
Collection of consideration	30 days
DS \| Maximum
Segment Reporting Information [Line Items]
Collection of consideration	60 days
DIS business
Segment Reporting Information [Line Items]
Percentage of net revenues	97.00%	97.00%	96.00%
Percentage of net accounts receivable	97.00%	97.00%
DIS business \| Minimum
Segment Reporting Information [Line Items]
Percentage of net revenues	95.00%	95.00%	95.00%
DIS business \| Healthcare insurers:
Segment Reporting Information [Line Items]
Percentage of net revenues	42.00%	37.00%	36.00%
Percentage of net accounts receivable	32.00%	34.00%
DIS business \| Healthcare insurers: \| Fee-for-service
Segment Reporting Information [Line Items]
Percentage of net revenues	39.00%	34.00%	33.00%
DIS business \| Healthcare insurers: \| Capitated
Segment Reporting Information [Line Items]
Percentage of net revenues	3.00%	3.00%	3.00%
DIS business \| Government payers
Segment Reporting Information [Line Items]
Percentage of net revenues	10.00%	11.00%	15.00%
Percentage of net accounts receivable	6.00%	6.00%
DIS business \| Client payers
Segment Reporting Information [Line Items]
Percentage of net revenues	33.00%	38.00%	32.00%
Percentage of net accounts receivable	38.00%	46.00%
DIS business \| Patients
Segment Reporting Information [Line Items]
Percentage of net revenues	12.00%	11.00%	13.00%
Period of billing fully reserve	210 days
Percentage of net accounts receivable	21.00%	11.00%
All other operating segments \| DS
Segment Reporting Information [Line Items]
Percentage of net revenues	3.00%	3.00%	4.00%
Percentage of net accounts receivable	3.00%	3.00%