SUPPLEMENTAL CASH FLOW & OTHER DATA (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow and Other Data [Line Items]
Depreciation expense	$ 220us-gaap_Depreciation	$ 204us-gaap_Depreciation	$ 207us-gaap_Depreciation
Amortization expense	94	79	80
Interest expense, net	(164)dgx_InterestExpenseNet	(159)dgx_InterestExpenseNet	(165)dgx_InterestExpenseNet
Interest paid	170us-gaap_InterestPaid	167us-gaap_InterestPaid	163us-gaap_InterestPaid
Income taxes paid	327us-gaap_IncomeTaxesPaid	568us-gaap_IncomeTaxesPaid	305us-gaap_IncomeTaxesPaid
Assets acquired under capital leases	12dgx_AssetsAcquiredUnderCapitalLease	13dgx_AssetsAcquiredUnderCapitalLease	6dgx_AssetsAcquiredUnderCapitalLease
Account payable associated with capital expenditures	26	28	0
Dividend payable	48	43	48
Fair value of assets acquired	853us-gaap_FairValueOfAssetsAcquired	280us-gaap_FairValueOfAssetsAcquired	51us-gaap_FairValueOfAssetsAcquired
Fair value of liabilities assumed	85us-gaap_LiabilitiesAssumed1	16us-gaap_LiabilitiesAssumed1
Fair value of net assets acquired	768dgx_FairValueOfNetAssetsAcquired	264dgx_FairValueOfNetAssetsAcquired	51dgx_FairValueOfNetAssetsAcquired
Merger consideration paid (payable)	(30)dgx_MergerConsiderationPaid	(50)dgx_MergerConsiderationPaid
Cash paid for business acquisitions	738dgx_CashPaidForBusinessAcquisitions	214dgx_CashPaidForBusinessAcquisitions	51dgx_CashPaidForBusinessAcquisitions
Less: cash acquired	10us-gaap_CashAcquiredFromAcquisition	1us-gaap_CashAcquiredFromAcquisition
Business acquisitions, net of cash acquired	728	213	51
Continuing Operations [Member]
Supplemental Cash Flow and Other Data [Line Items]
Depreciation expense	220	203	204
Interest expense	(167)	(162)	(168)
Interest income	3	3	3
Interest expense, net	$ (164)	$ (159)	$ (165)

The amount of fixed assets that an Entity acquires in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

No definition available.