DESCRIPTION OF BUSINESS DESCRIPTION OF BUSINESS (Details)	Dec. 31, 2012
Description of Business (Abstract)
Number of requisitions processed during the period	147,000,000

Number of requisitions processed during the period.

No definition available.

Name:	dgx_NumberOfRequisitionsProcessedDuringPeriod
Namespace Prefix:	dgx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant