DESCRIPTION OF BUSINESS DESCRIPTION OF BUSINESS (Details)	12 Months Ended
Dec. 31, 2014
Description of Business (Abstract)
Number of requisitions processed during the period	156,000,000

Number of requisitions processed during the period.

No definition available.

Name:	dgx_Numberofrequisitionsprocessedduringtheperiod
Namespace Prefix:	dgx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration