Segment Information (Narrative) (Details)	6 Months Ended
Jun. 30, 2015
Segment Reporting [Abstract]
Percentage of consolidated revenues and segment operating profit, less than 10%	10.00%

Percentage of consolidated revenue and segment operating profit, maximum.

No definition available.

Name:	ctsh_PercentageOfConsolidatedRevenueAndSegmentOperatingProfitMaximum
Namespace Prefix:	ctsh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration