COMMITMENTS AND CONTINGENCIES	12 Months Ended
Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Letters of Credit and Contractual Obligations The Company can issue letters of credit under its Secured Receivables Credit Facility and Senior Unsecured Revolving Credit Facility (see Note 14). In support of its risk management program, to ensure the Company’s performance or payment to third parties, $72 million in letters of credit under the Secured Receivables Credit Facility were outstanding as of December 31, 2023. The letters of credit primarily represent collateral for current and future automobile liability and workers’ compensation loss payments. The Company has certain noncancelable commitments, primarily under take-or-pay arrangements, to purchase products or services from various suppliers, mainly for consulting and other service agreements, and standing orders to purchase reagents and other laboratory supplies. As of December 31, 2023, the approximate total future purchase commitments are $793 million, of which $214 million are expected to be incurred in 2024, $352 million are expected to be incurred in 2025 through 2026 and the balance thereafter. Billing and Collection Agreement In September 2016, the Company entered into a ten-year agreement with a third party to outsource its billing and related operations for the majority of the Company’s revenues. Services under the agreement commenced during the fourth quarter of 2016. The agreement includes an annual fee, which is subject to adjustment based on certain changes in the Company's requisition volume and the achievement of various performance metrics. Contingent Lease Obligations The Company remains subject to contingent obligations under certain real estate leases, including real estate leases that were entered into by certain predecessor companies of a subsidiary prior to the Company's acquisition of the subsidiary. While over the course of many years, the title to certain properties and interest in the subject leases have been transferred to third parties and the subject leases have been amended several times by such third parties, the lessors have not formally released the subsidiary predecessor companies from their original obligations under the leases and therefore remain contingently liable in the event of default. The remaining terms of the lease obligations and the Company's corresponding indemnifications range up to 24 years. The lease payments under certain leases are subject to market value adjustments and contingent rental payments and therefore, the total contingent obligations under the leases cannot be precisely determined but are likely to total several hundred million dollars. A claim against the Company would be made only upon the current lessee's default and, in certain cases, after a series of claims and corresponding defaults by third parties that precede the Company in the order of liability. The Company also has certain indemnification rights from other parties to recover losses in the event of default on the lease obligations. The Company believes that the likelihood of its performance under these contingent obligations is remote and no liability has been recorded for any potential payments under the contingent lease obligations. Certain Legal Matters The Company may incur losses associated with these proceedings and investigations, but it is not possible to estimate the amount of loss or range of loss, if any, that might result from adverse judgments, settlements, fines, penalties, or other resolution of these proceedings and investigations based on the stage of these proceedings and investigations, the absence of specific allegations as to alleged damages, the uncertainty as to the certification of a class or classes and the size of any certified class, if applicable, and/or the lack of resolution of significant factual and legal issues. The Company has insurance coverage rights in place (limited in amount; subject to deductible) for certain potential costs and liabilities related to these proceedings and investigations. In 2020, two putative class action lawsuits were filed in the U.S. District Court for New Jersey against the Company and other defendants with respect to the Company’s 401(k) plan. The complaint alleges, among other things, that the fiduciaries of the 401(k) plan breached their duties by failing to disclose the expenses and risks of plan investment options, allowing unreasonable administration expenses to be charged to plan participants, and selecting and retaining high cost and poor performing investments. In October 2020, the court consolidated the two lawsuits under the caption In re: Quest Diagnostics ERISA Litigation and plaintiffs filed a consolidated amended complaint. In May 2021, the court denied the Company's motion to dismiss the complaint. Discovery has been completed. Plaintiffs' motion for class certification and the Company's motion for summary judgment are pending. On June 3, 2019, the Company reported that Retrieval-Masters Creditors Bureau, Inc./American Medical Collection Agency (“AMCA”) had informed the Company and Optum360 LLC that an unauthorized user had access to AMCA’s system between August 1, 2018 and March 30, 2019 (the “AMCA Data Security Incident”). Optum360 provides revenue management services to the Company, and AMCA provided debt collection services to Optum360. AMCA first informed the Company of the AMCA Data Security Incident on May 14, 2019. AMCA’s affected system included financial information (e.g., credit card numbers and bank account information), medical information and other personal information (e.g., social security numbers). Test results were not included. Neither Optum360’s nor the Company’s systems or databases were involved in the incident. AMCA also informed the Company that information pertaining to other laboratories’ customers was also affected. Following announcement of the AMCA Data Security Incident, AMCA sought protection under the U.S. bankruptcy laws. The bankruptcy proceeding has been dismissed. Numerous putative class action lawsuits were filed against the Company related to the AMCA Data Security Incident. The U.S. Judicial Panel on Multidistrict Litigation transferred the cases that were then still pending to, and consolidated them for pre-trial proceedings in, the U.S. District Court for New Jersey. In November 2019, the plaintiffs in the multidistrict proceeding filed a consolidated putative class action complaint against the Company and Optum360 that named additional individuals as plaintiffs and that asserted a variety of common law and statutory claims in connection with the AMCA Data Security Incident. In January 2020, the Company moved to dismiss the consolidated complaint; the motion to dismiss was granted in part and denied in part. Plaintiffs filed an amended complaint, which the Company also moved to dismiss. The motion was granted in part and denied in part. Discovery is proceeding. In addition, a group of state attorney general offices are investigating the Company in connection with the AMCA Data Security Incident. The Company is cooperating with the investigation. ReproSource Fertility Diagnostics, Inc. (“ReproSource”), a subsidiary of the Company, is subject to two putative class action lawsuits related to a data security incident that occurred in August 2021 in which plaintiffs allege that an unauthorized party accessed or acquired protected health information and personally identifiable information of ReproSource patients. Bickham v. ReproSource Fertility Diagnostics, Inc. is pending in the U.S. District Court for the District of Massachusetts, and Trouville v. ReproSource Fertility Diagnostics, Inc. is pending in the U.S. District Court for the Eastern District of California. A third case filed in the U.S. District Court for the District of Massachusetts, Gordon v. ReproSource Fertility Diagnostics, Inc., was consolidated into the Bickham case. The Bickham and Trouville complaints seek to represent a class of all individuals potentially impacted by the August 2021 data security incident, and generally allege that ReproSource, among other claims, failed to adequately safeguard patients’ private information. On January 10, 2024, ReproSource agreed to settle the Bickham case on a class-wide basis. The settlement is pending approval by the District Court. If approved, ReproSource will receive a full release for all claims that the settlement class might possess arising out of the August 2021 data security incident. A motion to dismiss, stay, or transfer the Trouville case to the U.S. District Court for the District of Massachusetts remains pending. The Company is subject to a putative class action entitled Cole, et al. v Quest Diagnostics Incorporated, which was filed in the U. S. District Court for the Eastern District of California, for allegedly conspiring with Facebook to track customers’ internet communications on Company web platforms without authorization, in violation of the California Invasion of Privacy Act and the California Confidentiality of Medical Information Act. The complaint alleged that the Company’s actions were an invasion of privacy and contributed to a loss of value in plaintiffs’ personally identifiable information. The Company moved to dismiss the case or, in the alternative, transfer venue to the U.S. District Court for New Jersey. Subsequently, plaintiffs filed an amended complaint, which the Company also moved to dismiss. The Company's motion to transfer the case was granted. The Company has refiled its motion to dismiss with the New Jersey District Court. As previously disclosed, in August 2011, the Company had received a subpoena from the U.S. Attorney for the Northern District of Georgia seeking various business records, including records related to the Company's compliance program, certain marketing materials, certain product offerings, and certain test ordering and other policies. The Company cooperated with the request. In 2021, a third amended complaint in a qui tam action filed in the U.S. District Court for the Northern District of Georgia was unsealed, which is related to the matter underlying the August 2011 subpoena. Both the U.S. Department of Justice and the State of Georgia declined to intervene in the action. The Company moved to dismiss the complaint and the complaint was dismissed without prejudice in August 2022. The relator subsequently filed a fourth amended complaint. The Company has moved to dismiss the fourth amended complaint. The Company also received subpoenas from the U.S. Attorney for the District of New Jersey. The subpoenas seek various records relating to the Company’s relationship with the New York Giants and adherence to certain company policies and federal laws. The Company is cooperating with the investigation. Other Legal Matters In the normal course of business, the Company has been named, from time to time, as a defendant in various legal actions, including arbitrations, class actions and other litigation, arising in connection with the Company's activities as a provider of diagnostic testing, information and services. These actions could involve claims for substantial compensatory and/or punitive damages or claims for indeterminate amounts of damages, and could have an adverse impact on the Company's client base and reputation. The Company is also involved, from time to time, in other reviews, investigations and proceedings by governmental agencies regarding the Company's business which may result in adverse judgments, settlements, fines, penalties, injunctions or other relief. The federal or state governments may bring claims based on the Company's current practices, which it believes are lawful. In addition, certain federal and state statutes, including the qui tam provisions of the federal False Claims Act, allow private individuals to bring lawsuits against healthcare companies on behalf of government or private payers. The Company is aware of lawsuits, and from time to time has received subpoenas, related to billing or other practices based on the False Claims Act or other federal and state statutes, regulations or other laws. The Company understands that there may be other pending qui tam claims brought by former employees or other "whistleblowers" as to which the Company cannot determine the extent of any potential liability. Management cannot predict the outcome of such matters. Although management does not anticipate that the ultimate outcome of such matters will have a material adverse effect on the Company's financial condition, given the high degree of judgment involved in establishing loss estimates related to these types of matters, the outcome of such matters may be material to the Company's consolidated results of operations or cash flows in the period in which the impact of such matters is determined or paid. These matters are in different stages. Some of these matters are in their early stages. Matters may involve responding to and cooperating with various government investigations and related subpoenas. As of December 31, 2023, the Company does not believe that material losses related to legal matters are probable. Reserves for legal matters totaled $6 million and $2 million as of December 31, 2023 and December 31, 2022, respectively. Reserves for General and Professional Liability Claims As a general matter, providers of clinical testing services may be subject to lawsuits alleging negligence or other similar legal claims. These suits could involve claims for substantial damages. Any professional liability litigation could also have an adverse impact on the Company's client base and reputation. The Company maintains various liability insurance coverages for, among other things, claims that could result from providing, or failing to provide, clinical testing services, including inaccurate testing results, and other exposures. The Company's insurance coverage limits its maximum exposure on individual claims; however, the Company is essentially self-insured for a significant portion of these claims. Reserves for such matters, including those associated with both asserted and incurred but not reported claims, are established on an undiscounted basis by considering actuarially determined losses based upon the Company's historical and projected loss experience. Such reserves totaled $173 million and $169 million as of December 31, 2023 and December 31, 2022, respectively. Management believes that established reserves and present insurance coverage are sufficient to cover currently estimated exposures.

The Company can issue letters of credit under its Secured Receivables Credit Facility and Senior Unsecured Revolving Credit Facility (see Note 14). In support of its risk management program, to ensure the Company’s performance or payment to third parties, $72 million in letters of credit under the Secured Receivables Credit Facility were outstanding as of December 31, 2023. The letters of credit primarily represent collateral for current and future automobile liability and workers’ compensation loss payments.

The Company has certain noncancelable commitments, primarily under take-or-pay arrangements, to purchase products or services from various suppliers, mainly for consulting and other service agreements, and standing orders to purchase reagents and other laboratory supplies. As of December 31, 2023, the approximate total future purchase commitments are $793 million, of which $214 million are expected to be incurred in 2024, $352 million are expected to be incurred in 2025 through 2026 and the balance thereafter.

In September 2016, the Company entered into a ten-year agreement with a third party to outsource its billing and related operations for the majority of the Company’s revenues. Services under the agreement commenced during the fourth quarter of 2016. The agreement includes an annual fee, which is subject to adjustment based on certain changes in the Company's requisition volume and the achievement of various performance metrics.

The Company remains subject to contingent obligations under certain real estate leases, including real estate leases that were entered into by certain predecessor companies of a subsidiary prior to the Company's acquisition of the subsidiary. While over the course of many years, the title to certain properties and interest in the subject leases have been transferred to third parties and the subject leases have been amended several times by such third parties, the lessors have not formally released the subsidiary predecessor companies from their original obligations under the leases and therefore remain contingently liable in the event of default. The remaining terms of the lease obligations and the Company's corresponding indemnifications range up to 24 years. The lease payments under certain leases are subject to market value adjustments and contingent rental payments and therefore, the total contingent obligations under the leases cannot be precisely determined but are likely to total several hundred million dollars. A claim against the Company would be made only upon the current lessee's default and, in certain cases, after a series of claims and corresponding defaults by third parties that precede the Company in the order of liability. The Company also has certain indemnification rights from other parties to recover losses in the event of default on the lease obligations. The Company believes that the likelihood of its performance under these contingent obligations is remote and no liability has been recorded for any potential payments under the contingent lease obligations.

The Company may incur losses associated with these proceedings and investigations, but it is not possible to estimate the amount of loss or range of loss, if any, that might result from adverse judgments, settlements, fines, penalties, or other resolution of these proceedings and investigations based on the stage of these proceedings and investigations, the absence of specific allegations as to alleged damages, the uncertainty as to the certification of a class or classes and the size of any certified class, if applicable, and/or the lack of resolution of significant factual and legal issues. The Company has insurance coverage rights in place (limited in amount; subject to deductible) for certain potential costs and liabilities related to these proceedings and investigations.

In 2020, two putative class action lawsuits were filed in the U.S. District Court for New Jersey against the Company and other defendants with respect to the Company’s 401(k) plan. The complaint alleges, among other things, that the fiduciaries of the 401(k) plan breached their duties by failing to disclose the expenses and risks of plan investment options, allowing unreasonable administration expenses to be charged to plan participants, and selecting and retaining high cost and poor performing investments. In October 2020, the court consolidated the two lawsuits under the caption In re: Quest Diagnostics ERISA Litigation and plaintiffs filed a consolidated amended complaint. In May 2021, the court denied the Company's motion to dismiss the complaint. Discovery has been completed. Plaintiffs' motion for class certification and the Company's motion for summary judgment are pending.

On June 3, 2019, the Company reported that Retrieval-Masters Creditors Bureau, Inc./American Medical Collection Agency (“AMCA”) had informed the Company and Optum360 LLC that an unauthorized user had access to AMCA’s system between August 1, 2018 and March 30, 2019 (the “AMCA Data Security Incident”). Optum360 provides revenue management services to the Company, and AMCA provided debt collection services to Optum360. AMCA first informed the Company of the AMCA Data Security Incident on May 14, 2019. AMCA’s affected system included financial information (e.g., credit card numbers and bank account information), medical information and other personal information (e.g., social security numbers). Test results were not included. Neither Optum360’s nor the Company’s systems or databases were involved in the incident. AMCA also informed the Company that information pertaining to other laboratories’ customers was also affected. Following announcement of the AMCA Data Security Incident, AMCA sought protection under the U.S. bankruptcy laws. The bankruptcy proceeding has been dismissed.

Numerous putative class action lawsuits were filed against the Company related to the AMCA Data Security Incident. The U.S. Judicial Panel on Multidistrict Litigation transferred the cases that were then still pending to, and consolidated them for pre-trial proceedings in, the U.S. District Court for New Jersey. In November 2019, the plaintiffs in the multidistrict proceeding filed a consolidated putative class action complaint against the Company and Optum360 that named additional individuals as plaintiffs and that asserted a variety of common law and statutory claims in connection with the AMCA Data Security Incident. In January 2020, the Company moved to dismiss the consolidated complaint; the motion to dismiss was granted in part and denied in part. Plaintiffs filed an amended complaint, which the Company also moved to dismiss. The motion was granted in part and denied in part. Discovery is proceeding.

ReproSource Fertility Diagnostics, Inc. (“ReproSource”), a subsidiary of the Company, is subject to two putative class action lawsuits related to a data security incident that occurred in August 2021 in which plaintiffs allege that an unauthorized party accessed or acquired protected health information and personally identifiable information of ReproSource patients. Bickham v. ReproSource Fertility Diagnostics, Inc. is pending in the U.S. District Court for the District of Massachusetts, and Trouville v. ReproSource Fertility Diagnostics, Inc. is pending in the U.S. District Court for the Eastern District of California. A third case filed in the U.S. District Court for the District of Massachusetts, Gordon v. ReproSource Fertility Diagnostics, Inc., was consolidated into the Bickham case. The Bickham and Trouville complaints seek to represent a class of all individuals potentially impacted by the August 2021 data security incident, and generally allege that ReproSource, among other claims, failed to adequately safeguard patients’ private information.

On January 10, 2024, ReproSource agreed to settle the Bickham case on a class-wide basis. The settlement is pending approval by the District Court. If approved, ReproSource will receive a full release for all claims that the settlement class might possess arising out of the August 2021 data security incident. A motion to dismiss, stay, or transfer the Trouville case to the U.S. District Court for the District of Massachusetts remains pending.

The Company is subject to a putative class action entitled Cole, et al. v Quest Diagnostics Incorporated, which was filed in the U. S. District Court for the Eastern District of California, for allegedly conspiring with Facebook to track customers’ internet communications on Company web platforms without authorization, in violation of the California Invasion of Privacy Act and the California Confidentiality of Medical Information Act. The complaint alleged that the Company’s actions were an invasion of privacy and contributed to a loss of value in plaintiffs’ personally identifiable information. The Company moved to dismiss the case or, in the alternative, transfer venue to the U.S. District Court for New Jersey. Subsequently, plaintiffs filed an amended complaint, which the Company also moved to dismiss. The Company's motion to transfer the case was granted. The Company has refiled its motion to dismiss with the New Jersey District Court.

As previously disclosed, in August 2011, the Company had received a subpoena from the U.S. Attorney for the Northern District of Georgia seeking various business records, including records related to the Company's compliance program, certain marketing materials, certain product offerings, and certain test ordering and other policies. The Company cooperated with the request. In 2021, a third amended complaint in a qui tam action filed in the U.S. District Court for the Northern District of Georgia was unsealed, which is related to the matter underlying the August 2011 subpoena. Both the U.S. Department of Justice and the State of Georgia declined to intervene in the action. The Company moved to dismiss the complaint and the complaint was dismissed without prejudice in August 2022. The relator subsequently filed a fourth amended complaint. The Company has moved to dismiss the fourth amended complaint.

In the normal course of business, the Company has been named, from time to time, as a defendant in various legal actions, including arbitrations, class actions and other litigation, arising in connection with the Company's activities as a provider of diagnostic testing, information and services. These actions could involve claims for substantial compensatory and/or punitive damages or claims for indeterminate amounts of damages, and could have an adverse impact on the Company's client base and reputation.

The federal or state governments may bring claims based on the Company's current practices, which it believes are lawful. In addition, certain federal and state statutes, including the qui tam provisions of the federal False Claims Act, allow private individuals to bring lawsuits against healthcare companies on behalf of government or private payers. The Company is aware of lawsuits, and from time to time has received subpoenas, related to billing or other practices based on the False Claims Act or other federal and state statutes, regulations or other laws. The Company understands that there may be other pending qui tam claims brought by former employees or other "whistleblowers" as to which the Company cannot determine the extent of any potential liability.

Management cannot predict the outcome of such matters. Although management does not anticipate that the ultimate outcome of such matters will have a material adverse effect on the Company's financial condition, given the high degree of judgment involved in establishing loss estimates related to these types of matters, the outcome of such matters may be material to the Company's consolidated results of operations or cash flows in the period in which the impact of such matters is determined or paid.