Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

+ Details

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

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479907/805-20-50-5

+ Details

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

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ctsh_AustinCSIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ctsh_UtegrationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ctsh_OneSourceVirtualMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ctsh_MobicaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ctsh_ThirderaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ctsh_BelcanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Business Combinations (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
	Aug. 26, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Jan. 22, 2024	Mar. 10, 2023	Jan. 01, 2023	Dec. 19, 2022	Dec. 15, 2022
Business Combinations [Abstract]
Revenue from acquisitions		$ 384	$ 130
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		1,615	409	$ 367
Revenue from acquisitions		$ 384	$ 130
AustinCSI
Business Combinations [Abstract]
Percentage of voting interests acquired									100.00%
Business Acquisition [Line Items]
Percentage of voting interests acquired									100.00%
Utegration
Business Combinations [Abstract]
Percentage of voting interests acquired								100.00%
Business Acquisition [Line Items]
Percentage of voting interests acquired								100.00%
OneSource Virtual
Business Combinations [Abstract]
Percentage of voting interests acquired							100.00%
Business Acquisition [Line Items]
Percentage of voting interests acquired							100.00%
Mobica
Business Combinations [Abstract]
Percentage of voting interests acquired						100.00%
Business Acquisition [Line Items]
Percentage of voting interests acquired						100.00%
Thirdera
Business Combinations [Abstract]
Percentage of voting interests acquired					100.00%
Business Acquisition [Line Items]
Percentage of voting interests acquired					100.00%
Belcan
Business Combinations [Abstract]
Percentage of voting interests acquired	100.00%
Business Acquisition [Line Items]
Percentage of voting interests acquired	100.00%
Payments to Acquire Businesses, Net of Cash Acquired	$ 1,195
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	1,470,589
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 113