QUEST DIAGNOSTICS INC, 10-Q filed on 10/21/2025
Quarterly Report
v3.25.3
Cover Page - shares
 9 Months Ended
Sep. 30, 2025
Oct. 15, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2025  
Document Transition Report false  
Entity File Number 001-12215  
Entity Registrant Name Quest Diagnostics Inc  
Entity Central Index Key 0001022079  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 16-1387862  
Entity Address, Address Line One 500 Plaza Drive  
Entity Address, City or Town Secaucus,  
Entity Address, State or Province NJ  
Entity Address, Postal Zip Code 07094  
City Area Code (973)  
Local Phone Number 520-2700  
Title of 12(b) Security Common Stock, $0.01 Par Value  
Trading Symbol DGX  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   111,242,362
v3.25.3
CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Income Statement [Abstract]        
Net revenues $ 2,816 $ 2,488 $ 8,229 $ 7,251
Operating costs and expenses and other operating income:        
Cost of services 1,867 1,677 5,474 4,865
Selling, general and administrative 501 448 1,463 1,304
Amortization of intangible assets 39 32 117 90
Other operating expense, net 23 1 5 7
Total operating costs and expenses, net 2,430 2,158 7,059 6,266
Operating income 386 330 1,170 985
Other income (expense):        
Interest expense, net (66) (49) (200) (136)
Other income, net 8 15 18 27
Total non-operating expense, net (58) (34) (182) (109)
Income before income taxes and equity in earnings of equity method investees 328 296 988 876
Income tax expense (77) (65) (233) (205)
Equity in earnings of equity method investees, net of taxes 8 6 35 14
Net income 259 237 790 685
Less: Net income attributable to noncontrolling interests 14 11 43 36
Net income attributable to Quest Diagnostics $ 245 $ 226 $ 747 $ 649
Earnings per share attributable to Quest Diagnostics’ common stockholders:        
Basic (in dollars per share) $ 2.18 $ 2.01 $ 6.66 $ 5.80
Diluted (in dollars per share) $ 2.16 $ 1.99 $ 6.57 $ 5.74
Weighted average common shares outstanding:        
Basic (in Shares) 112 112 112 111
Diluted (in Shares) 113 113 113 112
v3.25.3
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Statement of Comprehensive Income [Abstract]        
Net income $ 259 $ 237 $ 790 $ 685
Other comprehensive income (loss):        
Foreign currency translation adjustment (24) 1 48 (4)
Net deferred gain on cash flow hedges, net of taxes 0 3 0 3
Other comprehensive (loss) income (24) 4 48 (1)
Comprehensive income 235 241 838 684
Less: Comprehensive income attributable to noncontrolling interests 14 11 43 36
Comprehensive income attributable to Quest Diagnostics $ 221 $ 230 $ 795 $ 648
v3.25.3
CONSOLIDATED BALANCE SHEETS - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Assets    
Cash and cash equivalents $ 432 $ 549
Accounts receivable, net of allowance for credit losses of $26 and $29 as of September 30, 2025 and December 31, 2024, respectively 1,456 1,304
Inventories 186 188
Prepaid expenses and other current assets 333 351
Total current assets 2,407 2,392
Property, plant and equipment, net 2,145 2,113
Operating lease right-of-use assets 649 651
Goodwill 8,901 8,856
Intangible assets, net 1,662 1,763
Investments in equity method investees 137 123
Other assets 296 255
Total assets 16,197 16,153
Current liabilities:    
Accounts payable and accrued expenses 1,457 1,394
Current portion of long-term debt 504 602
Current portion of long-term operating lease liabilities 173 173
Total current liabilities 2,134 2,169
Long-term debt 5,171 5,615
Long-term operating lease liabilities 534 535
Other liabilities 982 938
Commitments and contingencies
Redeemable noncontrolling interest 81 83
Quest Diagnostics stockholders’ equity:    
Common stock, par value $0.01 per share; 600 shares authorized as of both September 30, 2025 and December 31, 2024; 162 shares issued as of both September 30, 2025 and December 31, 2024 2 2
Additional paid-in capital 2,355 2,361
Retained earnings 9,837 9,360
Accumulated other comprehensive loss (40) (88)
Treasury stock, at cost; 51 shares as of both September 30, 2025 and December 31, 2024 (4,896) (4,857)
Total Quest Diagnostics stockholders’ equity 7,258 6,778
Noncontrolling interests 37 35
Total stockholders’ equity 7,295 6,813
Total liabilities and stockholders’ equity $ 16,197 $ 16,153
v3.25.3
CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)
shares in Millions, $ in Millions
Sep. 30, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Allowance for doubtful accounts $ 26 $ 29
Common stock, par value (in dollars per share) $ 0.01 $ 0.01
Common stock, shares authorized (in shares) 600 600
Common stock, shares issued (in shares) 162 162
Treasury stock (in shares) 51 51
v3.25.3
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Cash flows from operating activities:    
Net income $ 790 $ 685
Adjustments to reconcile net income to net cash provided by operating activities:    
Depreciation and amortization 425 358
Provision for credit losses 2 4
Deferred income tax expense (benefit) 118 (21)
Stock-based compensation expense 63 61
Other, net 37 17
Changes in operating assets and liabilities:    
Accounts receivable (153) (140)
Accounts payable and accrued expenses 113 (102)
Income taxes payable (1) 31
Other assets and liabilities, net 27 (23)
Net cash provided by operating activities 1,421 870
Cash flows from investing activities:    
Business acquisitions, net of cash acquired (51) (1,781)
Capital expenditures (369) (302)
Other investing activities, net (20) 37
Net cash used in investing activities (440) (2,046)
Cash flows from financing activities:    
Proceeds from borrowings 410 1,846
Repayments of debt (1,011) (302)
Purchases of treasury stock (150) 0
Exercise of stock options 61 52
Employee payroll tax withholdings on stock issued under stock-based compensation plans (44) (24)
Dividends paid (263) (247)
Distributions to noncontrolling interest partners (43) (35)
Other financing activities, net (61) (36)
Net cash (used in) provided by financing activities (1,101) 1,254
Effect of exchange rate changes on cash and cash equivalents and restricted cash 3 0
Net change in cash and cash equivalents and restricted cash (117) 78
Cash and cash equivalents and restricted cash, beginning of period 549 686
Cash and cash equivalents and restricted cash, end of period $ 432 $ 764
v3.25.3
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)
$ in Millions
Total
Common Stock
Additional Paid-In Capital
Retained Earnings
Accumulated Other Compre- hensive Loss
Treasury Stock, at Cost
Non- controlling Interests
Balance, shares at Dec. 31, 2023   111,000,000          
Balance at Dec. 31, 2023 $ 6,342 $ 2 $ 2,320 $ 8,825 $ (14) $ (4,826) $ 35
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 681     649     32
Other comprehensive income (loss), net of taxes (1)       (1)    
Dividends declared (252)     (252)      
Distributions to noncontrolling interest partners (35)           (35)
Issuance of common stock under benefit plans 20   (40)     60  
Stock-based compensation expense 61   61        
Exercise of stock options, shares   1,000,000          
Exercise of stock options 52         52  
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans (24)   (6)     $ (18)  
Purchases of treasury stock, shares           0  
Acquisition of additional ownership interest in subsidiary (3)   (3)        
Balance, shares at Sep. 30, 2024   112,000,000          
Balance at Sep. 30, 2024 6,841 $ 2 2,332 9,222 (15) $ (4,732) 32
Balance, shares at Jun. 30, 2024   111,000,000          
Balance at Jun. 30, 2024 6,656 $ 2 2,314 9,080 (19) (4,760) 39
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 236     226     10
Other comprehensive income (loss), net of taxes 4       4    
Dividends declared (84)     (84)      
Distributions to noncontrolling interest partners (17)           (17)
Issuance of common stock under benefit plans 7   1     6  
Stock-based compensation expense 19   19        
Exercise of stock options, shares   1,000,000          
Exercise of stock options 24   1     23  
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans (1)         (1)  
Acquisition of additional ownership interest in subsidiary (3)   (3)        
Balance, shares at Sep. 30, 2024   112,000,000          
Balance at Sep. 30, 2024 6,841 $ 2 2,332 9,222 (15) (4,732) 32
Balance, shares at Dec. 31, 2024   111,000,000          
Balance at Dec. 31, 2024 6,813 $ 2 2,361 9,360 (88) (4,857) 35
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 784     747     37
Other comprehensive income (loss), net of taxes 48       48    
Dividends declared (270)     (270)      
Distributions to noncontrolling interest partners (35)           (35)
Issuance of common stock under benefit plans, shares   1,000,000          
Issuance of common stock under benefit plans 21   (52)     73  
Stock-based compensation expense 63   63        
Exercise of stock options 65   3     62  
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans (44)   (20)     $ (24)  
Purchases of treasury stock, shares   (1,000,000)       (900,000)  
Purchases of treasury stock (150)         $ (150)  
Balance, shares at Sep. 30, 2025   111,000,000          
Balance at Sep. 30, 2025 7,295 $ 2 2,355 9,837 (40) (4,896) 37
Balance, shares at Jun. 30, 2025   112,000,000          
Balance at Jun. 30, 2025 7,265 $ 2 2,332 9,682 (16) (4,772) 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income 257     245     12
Other comprehensive income (loss), net of taxes (24)       (24)    
Dividends declared (90)     (90)      
Distributions to noncontrolling interest partners (12)           (12)
Issuance of common stock under benefit plans 8   2     6  
Stock-based compensation expense 20   20        
Exercise of stock options 23   2     21  
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans (2)   (1)     (1)  
Purchases of treasury stock, shares   (1,000,000)          
Purchases of treasury stock (150)         (150)  
Balance, shares at Sep. 30, 2025   111,000,000          
Balance at Sep. 30, 2025 $ 7,295 $ 2 $ 2,355 $ 9,837 $ (40) $ (4,896) $ 37
v3.25.3
DESCRIPTION OF BUSINESS
 9 Months Ended
Sep. 30, 2025
Description of Business (Abstract)  
DESCRIPTION OF BUSINESS DESCRIPTION OF BUSINESS
    
    Background
    
    Quest Diagnostics Incorporated and its subsidiaries ("Quest Diagnostics" or the "Company") work across the healthcare ecosystem to create a healthier world, one life at a time. The Company's diagnostic information services ("DIS") business provides diagnostic insights from the results of its laboratory testing to empower people, physicians, and organizations to take action to improve health outcomes. Derived from one of the world's largest databases of de-identifiable clinical lab results, the Company's diagnostic insights reveal new avenues to identify and treat disease, inspire healthy behaviors and improve healthcare management. In the right hands and with the right context, the Company's diagnostic insights can inspire actions that transform lives and create a healthier world. The Company provides services to a broad range of customers within its primary customer channels - physicians (including those associated with accountable care organizations ("ACOs") and Federally Qualified Health Centers ("FQHCs")), hospitals, and patients and consumers. Other customers include health plans, employers, emerging retail healthcare providers, government agencies, pharmaceutical companies and other commercial clinical laboratories. The Company offers broad access to clinical testing through a network of laboratories, patient service centers, phlebotomists in physician offices, and connectivity resources, including call centers and mobile phlebotomists, nurses and other health and wellness professionals. The Company's large in-house staff of medical and scientific experts, including medical directors, scientific directors, genetic counselors and board-certified geneticists, provide medical and scientific consultation to healthcare providers and patients regarding the Company's tests and test results, and help them best utilize Quest Diagnostics' services to improve outcomes and enhance satisfaction. The Company's Diagnostic Solutions ("DS") group, which represents the balance of the Company's consolidated net revenues, includes the Company's risk assessment services business, which offers solutions for insurers, and the Company's healthcare information technology businesses, which offer solutions for healthcare providers and payers.
v3.25.3
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 9 Months Ended
Sep. 30, 2025
Accounting Policies [Abstract]  
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
    Basis of Presentation
    
    The interim unaudited consolidated financial statements reflect all adjustments which in the opinion of management are necessary for a fair statement of results of operations, comprehensive income, financial condition, cash flows and stockholders' equity for the periods presented. Except as otherwise disclosed, all such adjustments are of a normal recurring nature. Operating results for the interim periods are not necessarily indicative of the results that may be expected for the full year. These interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in the Company’s 2024 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2024 but does not include all the disclosures required by accounting principles generally accepted in the United States (“GAAP”).

    The accounting policies of the Company are the same as those set forth in Note 2 to the audited consolidated financial statements contained in the Company’s 2024 Annual Report on Form 10-K.

    Use of Estimates
    
    The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

    Earnings Per Share

    The Company's unvested restricted stock units that contain non-forfeitable rights to dividends are participating securities and, therefore, are included in the earnings allocation in computing earnings per share using the two-class method. Basic earnings per common share is calculated by dividing net income attributable to Quest Diagnostics, adjusted for earnings allocated to participating securities, by the weighted average number of common shares outstanding. Diluted earnings per common share is calculated by dividing net income attributable to Quest Diagnostics, adjusted for earnings allocated to
participating securities, by the weighted average number of common shares outstanding after giving effect to all potentially dilutive common shares outstanding during the period. Potentially dilutive common shares include the dilutive effect of outstanding stock options and performance share units granted under the Company's Amended and Restated Employee Long-Term Incentive Plan (“ELTIP”) and its Amended and Restated Non-Employee Director Long-Term Incentive Plan (“DLTIP”), as well as the dilutive effect of accelerated share repurchase agreements, if applicable. Earnings allocable to participating securities include the portion of dividends declared as well as the portion of undistributed earnings during the period allocable to participating securities.

    New Accounting Standards to be Adopted

    In December 2023, the Financial Accounting Standards Board ("FASB") issued a new accounting standard which will require companies to make additional income tax disclosures. The pronouncement is effective for annual filings for the year ended December 31, 2025. The Company does not expect the adoption of this standard to have a material impact on its results of operations, financial position or cash flows.

    In November 2024, the FASB issued a new accounting standard which will require companies to disaggregate certain income statement expenses. The pronouncement is effective for annual filings for the year ended December 31, 2027 and for interim periods within the year ended December 31, 2028. The Company does not expect the adoption of this standard to have a material impact on its results of operations, financial position or cash flows.

    In September 2025, the FASB issued a new accounting standard which impacts internal-use software accounting by removing all references to software development project stages such that the guidance is neutral to different software development methods. The pronouncement is effective for annual filings for the year ended December 31, 2028 and for interim periods within such year. The Company is currently evaluating the impact of the standard.

    In July 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted. The OBBBA makes permanent key elements of the Tax Cuts and Jobs Act of 2017, including 100% bonus depreciation, domestic research cost expensing and the business interest expense limitation, among other tax changes. Many of the tax provisions of the OBBBA are designed to accelerate tax deductions, which could lead to lower cash tax payments. The new legislation has multiple effective dates, with certain provisions effective in 2025 and others in the future. While the Company continues to assess the impact of the tax provisions of the OBBBA on its consolidated financial statements, the Company currently believes that the tax provisions of the legislation are not expected to have a material impact on the Company’s statement of operations. The Company's consolidated deferred income tax liabilities as of September 30, 2025 and December 31, 2024 were $378 million and $278 million, respectively. The increase was principally due to the domestic research cost expensing and bonus depreciation elements of the OBBBA.
v3.25.3
EARNINGS PER SHARE
 9 Months Ended
Sep. 30, 2025
Earnings Per Share [Abstract]  
EARNINGS (LOSS) PER SHARE EARNINGS PER SHARE
    The computation of basic and diluted earnings per common share was as follows (in millions, except per share data):
Three Months Ended September 30,Nine Months Ended September 30,
 2025202420252024
Amounts attributable to Quest Diagnostics’ common stockholders:    
Net income attributable to Quest Diagnostics$245 $226 $747 $649 
Less: Earnings allocated to participating securities2 1 4 3 
Earnings available to Quest Diagnostics’ common stockholders – basic and diluted
$243 $225 $743 $646 
Weighted average common shares outstanding – basic112 112 112 111 
Effect of dilutive securities:    
Stock options and performance share units1 1 1 1 
Weighted average common shares outstanding – diluted113 113 113 112 
Earnings per share attributable to Quest Diagnostics’ common stockholders:    
Basic$2.18 $2.01 $6.66 $5.80 
Diluted$2.16 $1.99 $6.57 $5.74 
    

    The following securities were not included in the calculation of diluted earnings per share due to their antidilutive effect:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Stock options and performance share units— — — 1 
v3.25.3
RESTRUCTURING ACTIVITIES AND IMPAIRMENT CHARGES
 9 Months Ended
Sep. 30, 2025
Restructuring and Related Activities [Abstract]  
RESTRUCTURING ACTIVITIES AND IMPAIRMENT CHARGES RESTRUCTURING ACTIVITIES AND IMPAIRMENT CHARGES
    Invigorate Program

    The Company is engaged in a multi-year program called Invigorate, which includes structured plans to drive savings and improve productivity across the value chain, including in such areas as patient services, logistics and laboratory operations, revenue services, information technology and procurement. The Invigorate program aims to deliver 3% annual cost savings and productivity improvements to partially offset pressures from the current inflationary environment, including labor and benefit cost increases and reimbursement pressures. The Company is leveraging automation and artificial intelligence to improve productivity and also improve quality across the entire value chain, not just in the laboratory. Other areas of focus include reducing denials and patient concessions, enhancing the digital experience, and selecting and retaining talent.

    Restructuring and Impairment Charges
    
    The following table provides a summary of the Company's pre-tax restructuring and impairment charges for the three and nine months ended September 30, 2025 and 2024:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Employee separation costs$6 $7 $18 $21 
Asset impairment charges5 — 29 — 
Total restructuring and impairment charges$11 $7 $47 $21 
    The Company's pre-tax restructuring charges for the three and nine months ended September 30, 2025 included $6 million and $18 million, respectively, of employee separation costs associated with various workforce reduction initiatives as the Company continued to restructure its organization. Additionally, during the three and nine months ended September 30, 2025, the Company recorded impairment charges of $5 million and $29 million, respectively, on certain long-lived assets related to the exit of a business. Of the total restructuring and impairment charges incurred during the three months ended September 30, 2025, $2 million, $4 million and $5 million were recorded in cost of services, selling, general and administrative expenses and other operating expense, net, respectively. Of the total restructuring and impairment charges incurred during the nine months ended September 30, 2025, $8 million, $10 million and $29 million were recorded in cost of services, selling, general and administrative expenses, and other operating expense, net, respectively.

    The Company's pre-tax restructuring charges for the three and nine months ended September 30, 2024 were $7 million and $21 million, respectively, entirely related to employee separation costs associated with various workforce reduction initiatives as the Company continued to restructure its organization. Of the total restructuring charges incurred during the three months ended September 30, 2024, $4 million and $3 million were recorded in cost of services and selling, general and administrative expenses, respectively. Of the total restructuring charges incurred during the nine months ended September 30, 2024, $12 million and $9 million were recorded in cost of services and selling, general and administrative expenses, respectively.
    
    Charges for all periods presented were primarily recorded in the Company's DIS business.

    The restructuring liability as of September 30, 2025 and December 31, 2024, which is included in accounts payable and accrued expenses, was $14 million and $13 million, respectively.
v3.25.3
BUSINESS ACQUISITIONS
 9 Months Ended
Sep. 30, 2025
Business Combination [Abstract]  
BUSINESS ACQUISITIONS BUSINESS ACQUISITIONS
    Acquisition of LifeLabs

    On August 23, 2024, the Company acquired all of the issued and outstanding common shares of LifeLabs Inc. and all of the partnership interests of BPC Lab Finance LP (collectively, "LifeLabs") in an all-cash transaction for approximately CAN $1.35 billion (approximately USD $1 billion), net of cash acquired. LifeLabs provides laboratory diagnostic information and digital health connectivity systems in Canada. The Company recorded the assets acquired and liabilities assumed based on a preliminary purchase price allocation. During the nine months ended September 30, 2025, the Company finalized its purchase price allocation and recorded a $9 million increase to deferred income tax assets and a corresponding decrease to goodwill. The measurement period adjustment did not impact the Company's consolidated results of operations.

    The following unaudited pro forma combined financial information reflects the consolidated statement of operations of the Company as if the acquisition of LifeLabs had occurred as of January 1, 2023. The pro forma information includes adjustments primarily related to the amortization of acquired intangible assets, interest expense associated with debt of LifeLabs which was extinguished prior to the acquisition, interest expense associated with senior notes issued to fund the acquisition, the impact on depreciation expense of recording acquired property, plant and equipment at fair value, and transaction costs related to the LifeLabs acquisition. The pro forma combined financial information does not include the estimated annual synergies expected to be realized upon completion of the integration of LifeLabs and therefore is not indicative of the results of operations as they would have been had the transaction been effected on the assumed date (in millions, except per share data).
Three Months Ended September 30, 2024Nine Months Ended September 30, 2024
Pro forma net revenues$2,588 $7,700 
Pro forma net income attributable to Quest Diagnostics$222 $647 
Pro forma earnings per share attributable to Quest Diagnostics' common stockholders:
Basic$1.97 $5.78 
Diluted$1.95 $5.72 
    
    Acquisition of select assets of Spectra Laboratories

    During February 2025, the Company entered into a definitive agreement to acquire select clinical testing assets and select dialysis-related water testing assets of Fresenius Medical Care's wholly-owned Spectra Laboratories, a leading provider of renal-specific laboratory testing services in the U.S.

    On August 4, 2025, the acquisition of the select clinical testing assets closed and the Company paid $34 million of cash consideration for such business. Based on the preliminary purchase price allocation, which may be revised as additional information becomes available during the measurement period, the assets acquired and liabilities assumed primarily consist of $25 million of tax-deductible goodwill and $9 million of customer-related intangible assets. The intangible assets are being amortized over a useful life of 15 years.

    The acquisition of the select dialysis-related water testing assets is expected to close by the end of 2025 and such closing remains subject to customary closing conditions.

    The acquisition was accounted for under the acquisition method of accounting. As such, the assets acquired and liabilities assumed were recorded based on their estimated fair values as of the closing date. Supplemental pro forma combined financial information has not been presented as the impact of the acquisition is not material to the Company's consolidated financial statements. The goodwill recorded primarily includes the expected synergies resulting from combining the operations of the acquired entity with those of the Company and the value associated with an assembled workforce and other intangible assets that do not qualify for separate recognition. All of the goodwill acquired in connection with the acquisition has been allocated to the Company's DIS business. For further details regarding business segment information, see Note 12.

    For details regarding the Company's 2024 acquisitions, see Note 6 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10-K.    

    Venture with Corewell Health
    During August 2025, the Company and Corewell Health signed a definitive agreement to enter into a venture which will perform laboratory testing in the state of Michigan via a new laboratory facility. Equity ownership of the venture will be shared 51% by Quest and 49% by Corewell Health. The parties expect to complete the transaction during the first quarter of 2026 and they expect to construct a new laboratory facility to be operational during 2027. The transaction is subject to customary closing conditions.
v3.25.3
FAIR VALUE MEASUREMENTS
 9 Months Ended
Sep. 30, 2025
Fair Value Disclosures [Abstract]  
FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS
    Assets and Liabilities Measured at Fair Value on a Recurring Basis

    The following table provides a summary of the recognized assets and liabilities that are measured at fair value on a recurring basis:
Basis of Fair Value Measurements
Quoted Prices in Active Markets for Identical Assets/LiabilitiesSignificant Other Observable InputsSignificant Unobservable Inputs
September 30, 2025TotalLevel 1Level 2Level 3
Assets:    
Deferred compensation trading securities$82 $82 $— $— 
Cash surrender value of life insurance policies72 — 72 — 
Equity investments3 3 — — 
Fixed-to-variable interest rate swaps18 — 18 — 
Total$175 $85 $90 $— 
Liabilities:    
Deferred compensation liabilities$152 $— $152 $— 
Contingent consideration114 — — 114 
Total$266 $— $152 $114 
Redeemable noncontrolling interest$81 $— $— $81 
Basis of Fair Value Measurements
December 31, 2024TotalLevel 1Level 2Level 3
Assets:       
Deferred compensation trading securities$72 $72 $— $— 
Cash surrender value of life insurance policies64 — 64 — 
Total$136 $72 $64 $— 
Liabilities:    
Deferred compensation liabilities$140 $— $140 $— 
Contingent consideration106 — — 106 
Fixed-to-variable interest rate swaps34 — 34 — 
Total$280 $— $174 $106 
Redeemable noncontrolling interest$83 $— $— $83 
    
    A detailed description regarding the Company's fair value measurements is contained in Note 7 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10-K.    

    The Company offers certain employees the opportunity to participate in a non-qualified supplemental deferred compensation plan. A participant's deferrals, together with Company matching credits, are invested in a variety of participant-directed stock and bond mutual funds that are classified as trading securities. The trading securities are classified within Level
1 of the fair value hierarchy because the changes in the fair value of these securities are measured using quoted prices in active markets based on the market price per unit multiplied by the number of units held, exclusive of any transaction costs. A corresponding adjustment for changes in fair value of the trading securities is also reflected in the changes in fair value of the deferred compensation obligation. The deferred compensation liabilities are classified within Level 2 of the fair value hierarchy because their inputs are derived principally from observable market data by correlation to the trading securities.

    The Company offers certain employees the opportunity to participate in a non-qualified deferred compensation program. A participant's deferrals, together with Company matching credits, are “invested” at the direction of the employee in a hypothetical portfolio of investments which are tracked by an administrator. The Company purchases life insurance policies, with the Company named as beneficiary of the policies, for the purpose of funding the program's liability. Changes in the cash surrender value of the life insurance policies are based upon earnings and changes in the value of the underlying investments. Changes in the fair value of the deferred compensation obligation are derived using quoted prices in active markets based on the market price per unit multiplied by the number of units. The cash surrender value and the deferred compensation obligation are classified within Level 2 of the fair value hierarchy because their inputs are derived principally from observable market data by correlation to the hypothetical investments. Deferrals under the plan currently may only be made by participants who made deferrals under the plan in 2017.

    The Company's investment portfolio primarily includes equity investments comprised mostly of strategic holdings in companies concentrated in the life sciences and healthcare industries. Equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) with readily determinable fair values are measured at fair value in prepaid expenses and other current assets in the Company's consolidated balance sheet. Such equity investments are classified within Level 1 of the fair value hierarchy because the changes in the fair values of the securities are measured using quoted prices in active markets based on the market price per share multiplied by the number of shares held, exclusive of any transaction costs.

    The fair value measurements of the Company's fixed-to-variable interest rate swaps, classified within Level 2 of the fair value hierarchy, are model-derived valuations as of a given date, in which all significant inputs are observable in active markets including certain financial information and certain assumptions regarding past, present and future market conditions.

     During June 2023, the Company acquired Haystack Oncology, Inc. ("Haystack"), an early-stage oncology company focused on minimal residual disease testing to aid in the detection of residual or recurring cancer and better inform therapy decisions. In connection with the acquisition there is a contingent consideration obligation under which the seller can receive up to $100 million of additional consideration dependent upon the achievement of certain revenue benchmarks through 2028 and up to an additional $50 million of consideration dependent upon the Company receiving reimbursement coverage from the Centers for Medicare and Medicaid Services ("CMS"). The portion of the contingent consideration obligation which is dependent upon the achievement of certain revenue benchmarks was measured at fair value using a Monte Carlo method and is classified within Level 3 of the fair value hierarchy as the fair value is determined based on significant inputs that are not observable. Significant inputs include management’s estimate of revenue and other market inputs, including comparable company revenue volatility (35%) and a discount rate (10.5%). The portion of the contingent consideration obligation which is dependent upon the Company receiving reimbursement coverage from the CMS is also classified within Level 3 of the fair value hierarchy as the fair value is principally determined based on management's estimate, which is a significant input that is not observable. Additionally, the fair value of the entire contingent consideration obligation is also impacted by a market discount rate (5%) which adjusts the estimated payments to present value. The fair value of the contingent consideration obligation is not overly sensitive to movements in the comparable company revenue volatility or the discount rate used for the portion of the obligation that is dependent upon the achievement of certain revenue benchmarks. For example, changing the comparable company revenue volatility from 35% to 25% impacts the fair value by $4 million (assuming no other inputs are modified) and changing the discount rate from 10.5% to 7.0% impacts the fair value by $2 million (assuming no other inputs are modified).
    
    The Company has additional contingent consideration obligations in connection with other acquisitions. The liabilities related to such obligations are included in the amounts below.

    The following table provides a reconciliation of the beginning and ending balances of liabilities using significant unobservable inputs (Level 3):
Contingent Consideration
Balance, December 31, 2024
$106 
Total fair value adjustments included in earnings - unrealized8 
Balance, September 30, 2025$114 

    The $8 million net loss included in earnings associated with the change in the fair value of contingent consideration for the nine months ended September 30, 2025 is reported in other operating expense, net.    

    Of the aggregate $114 million contingent consideration obligation as of September 30, 2025, $63 million and $51 million were included in other liabilities and accounts payable and accrued expenses, respectively, in the Company's consolidated balance sheet. Of the aggregate $106 million contingent consideration obligation as of December 31, 2024, $101 million and $5 million were included in other liabilities and accounts payable and accrued expenses, respectively, in the Company's consolidated balance sheet.

    During the nine months ended September 30, 2025, the Company recorded a $29 million impairment charge on certain long-lived assets related to the exit of a business. The fair value measurement was classified within Level 3 of the fair value hierarchy as it was based on significant inputs that are not observable.

    In connection with the sale of an 18.9% noncontrolling interest in a subsidiary to UMass Memorial Medical Center ("UMass") on July 1, 2015, the Company granted UMass the right to require the Company to purchase all of its interest in the subsidiary at fair value commencing July 1, 2020. As of September 30, 2025, the redeemable noncontrolling interest was presented at its fair value. The fair value measurement of the redeemable noncontrolling interest is classified within Level 3 of the fair value hierarchy because the fair value is based on a discounted cash flow analysis that takes into account, among other items, the joint venture's expected future cash flows, long term growth rates, and a discount rate commensurate with economic risk.
    
    The carrying amounts of cash and cash equivalents, accounts receivable, and accounts payable and accrued expenses approximate fair value based on the short maturities of these instruments. As of September 30, 2025 and December 31, 2024, the fair value of the Company’s debt was estimated at $5.7 billion and $6.1 billion, respectively. Principally all of the Company's debt is classified within Level 1 of the fair value hierarchy because the fair value of the debt is estimated based on rates currently offered to the Company with identical terms and maturities, using quoted active market prices and yields, taking into account the underlying terms of the debt instruments.
v3.25.3
DEBT
 9 Months Ended
Sep. 30, 2025
Debt Disclosure [Abstract]  
DEBT DEBT
    
    During April 2025, the Company amended the agreement for its $750 million senior unsecured revolving credit facility (the “Credit Facility” or "Senior Unsecured Revolving Credit Facility") to extend the maturity to April 2030, while maintaining the borrowing capacity under the facility at $750 million. Under the Credit Facility, the Company can issue letters of credit totaling $150 million (see Note 11). Issued letters of credit reduce the available borrowing capacity under the Credit Facility. Additionally, the Credit Facility includes an additional $500 million uncommitted accordion which, if utilized, brings the total capacity under the facility to $1.3 billion. Interest on the Credit Facility is based on certain published rates plus an applicable margin based on changes in the Company's public debt ratings. At the option of the Company, it may elect to lock into Term Secured Overnight Financing Rate ("Term SOFR")-based interest rate contracts for periods up to six months. For interest on any U.S. Dollar-denominated outstanding amounts not covered under Term SOFR-based interest rate contracts, the Company can opt for an alternate base rate, which is calculated by reference to the prime rate, the federal funds rate or an adjusted Term SOFR rate. The Company also has the option to borrow in other currencies. As of September 30, 2025, the Company's borrowing rate for Term SOFR-based loans under the Credit Facility was adjusted Term SOFR plus 1.00%. The Credit Facility contains various covenants, including the maintenance of a financial leverage ratio, which could impact the Company's ability to, among other things, incur additional indebtedness. As of both September 30, 2025 and December 31, 2024, there were no outstanding borrowings under the Senior Unsecured Revolving Credit Facility.

    During the nine months ended September 30, 2025, the Company repaid in full the outstanding indebtedness under the Company's $600 million of 3.50% senior notes, which matured on March 30, 2025.

    The Company has $500 million of 3.45% senior notes due June 2026. The senior notes are included in current portion of long-term debt in the Company's September 30, 2025 consolidated balance sheet. Such notes were included in long-term debt in the Company's December 31, 2024 consolidated balance sheet.

    For further details regarding the Company's debt, see Note 13 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10 K.
v3.25.3
FINANCIAL INSTRUMENTS
 9 Months Ended
Sep. 30, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
FINANCIAL INSTRUMENTS FINANCIAL INSTRUMENTS
    The Company uses derivative financial instruments, from time to time, to manage its exposure to market risks for changes in interest rates and foreign currencies. This strategy includes the use of interest rate swap agreements, forward-starting interest rate swap agreements, interest rate lock agreements and foreign currency forward contracts to manage its exposure to movements in interest and currency rates. The Company has established policies and procedures for risk assessment and the approval, reporting and monitoring of derivative financial instrument activities. These policies prohibit holding or issuing derivative financial instruments for speculative purposes. The Company does not enter into derivative financial instruments that contain credit-risk-related contingent features or requirements to post collateral.

    Interest Rate Risk
    
    The Company is exposed to interest rate risk on its cash and cash equivalents and its debt obligations. Interest income earned on cash and cash equivalents may fluctuate as interest rates change; however, due to their relatively short maturities, the Company does not hedge these assets or their investment cash flows and the impact of interest rate risk is not material. The Company's debt obligations consist of fixed-rate and, from time to time, variable-rate debt instruments. The Company's primary objective is to achieve the lowest overall cost of funding while managing the variability in cash outflows within an acceptable range. In order to achieve this objective, the Company has historically entered into interest rate swap agreements.

    Interest rate swaps involve the periodic exchange of payments without the exchange of underlying principal or notional amounts. Net settlements between the counterparties are recognized as an adjustment to interest expense, net.

    Interest Rate Derivatives – Cash Flow Hedges

    From time to time, the Company has entered into various interest rate lock agreements and forward-starting interest rate swap agreements to hedge part of the Company's interest rate exposure associated with the variability in future cash flows attributable to changes in interest rates.
    
    Interest Rate Derivatives – Fair Value Hedges

    The Company maintains various fixed-to-variable interest rate swaps to convert a portion of the Company's long-term debt into variable interest rate debt.

    A summary of the notional amounts of these interest rate swap agreements as of September 30, 2025 and December 31, 2024 was as follows:
Notional Amount
Debt InstrumentSeptember 30, 2025December 31, 2024
5.00% Senior Notes due December 2034
$850 $700 
2.80% Senior Notes due June 2031
550 — 
6.40% Senior Notes due November 2033
400 — 
Total notional amounts$1,800 $700 
    The fixed-to-variable interest rate swap agreements in the table above have variable interest rates ranging from SOFR minus 1.36% to SOFR plus 2.48%.
    
    As of September 30, 2025 and December 31, 2024, the following amounts were recorded on the consolidated balance sheets related to cumulative basis adjustments for fair value hedges included in the carrying amount of long-term debt:

Carrying Amount of Hedged Long-Term DebtHedge Accounting Basis Adjustment (a)Carrying Amount of Hedged Long-Term DebtHedge Accounting Basis Adjustment (a)
Balance Sheet ClassificationSeptember 30, 2025September 30, 2025December 31, 2024December 31, 2024
Long-term debt$1,803 $20 $658 $(29)

(a) The balance includes $2 million and $5 million of remaining unamortized hedging adjustments on discontinued relationships as of September 30, 2025 and December 31, 2024, respectively.

    The following table presents the effect of fair value hedge accounting on the consolidated statement of operations for the three and nine months ended September 30, 2025:
Three Months Ended
September 30, 2025
Nine Months Ended September 30, 2025
Interest Expense, NetInterest Expense, Net
Total for line item in which the effects of fair value hedges are recorded$(66)$(200)
Gain (loss) on fair value hedging relationships:
Hedged items (Long-term debt)$(1)$(52)
Derivatives designated as hedging instruments$1 $52 

    A summary of the fair values of derivative instruments in the consolidated balance sheets was as follows:

September 30, 2025December 31, 2024
Balance Sheet
Classification		Fair ValueBalance Sheet
Classification		Fair Value
Derivatives Designated as Hedging Instruments   
Fixed-to-variable interest rate swap agreementsOther assets$18 Other liabilities$34 
    A detailed description regarding the Company's use of derivative financial instruments is contained in Note 15 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10-K.
v3.25.3
STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST
 9 Months Ended
Sep. 30, 2025
Equity [Abstract]  
STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST
    
    Stockholders' Equity    

    Changes in Accumulated Other Comprehensive Loss by Component

    Comprehensive income (loss) includes:

•Foreign currency translation adjustments;
•Net deferred gains (losses) on cash flow hedges, which represent deferred gains (losses), net of tax, on interest rate-related derivative financial instruments designated as cash flow hedges, net of amounts reclassified to interest expense (see Note 8); and
•Net changes in available-for-sale debt securities, which represent unrealized holding gains (losses), net of tax, on available-for-sale debt securities.

    For the three and nine months ended September 30, 2025 and 2024, the tax effects related to the deferred gains (losses) on cash flow hedges and net changes in available-for-sale debt securities were not material. Foreign currency translation adjustments related to indefinite investments in non-U.S. subsidiaries are not adjusted for income taxes.

    The changes in accumulated other comprehensive loss by component for the three and nine months ended September 30, 2025 were as follows:
For the Three Months Ended September 30, 2025Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, June 30, 2025$(21)$5 $(16)
Other comprehensive loss before reclassifications(24)— (24)
Net current period other comprehensive loss(24)— (24)
Balance, September 30, 2025$(45)$5 $(40)
For the Nine Months Ended September 30, 2025Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, December 31, 2024$(93)$5 $(88)
Other comprehensive income before reclassifications48 — 48 
Net current period other comprehensive income48 — 48 
Balance, September 30, 2025$(45)$5 $(40)
    The changes in accumulated other comprehensive loss by component for the three and nine months ended September 30, 2024 were as follows:
For the Three Months Ended September 30, 2024Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, June 30, 2024$(22)$3 $(19)
Other comprehensive income before reclassifications1 3 4 
Net current period other comprehensive income1 3 4 
Balance, September 30, 2024$(21)$6 $(15)
For the Nine Months Ended September 30, 2024Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, December 31, 2023$(17)$3 $(14)
Other comprehensive (loss) income before reclassifications(4)3 (1)
Net current period other comprehensive (loss) income(4)3 (1)
Balance, September 30, 2024$(21)$6 $(15)

    Dividend Program
    
    During each of the first three quarters of 2025, the Company's Board of Directors declared a quarterly cash dividend of $0.80 per common share. During each of the four quarters of 2024, the Company's Board of Directors declared a quarterly cash dividend of $0.75 per common share.
    
    Share Repurchase Program
    
    As of September 30, 2025, $0.7 billion remained available under the Company’s share repurchase authorization. The share repurchase authorization has no set expiration or termination date.
        
    Share Repurchases

    For the nine months ended September 30, 2025, the Company repurchased 0.9 million shares of its common stock for $150 million.

    For the nine months ended September 30, 2024, the Company repurchased no shares of its common stock.
        
    Shares Reissued from Treasury Stock

    For the nine months ended September 30, 2025 and 2024, the Company reissued 1.2 million shares and 1.0 million shares, respectively, from treasury stock under its Employee Stock Purchase Plan and its stock-based compensation program.

    For details regarding the Company's stock ownership and compensation plans, see Note 17 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10-K.
    
    Redeemable Noncontrolling Interest

    In connection with the sale of an 18.9% noncontrolling interest in a subsidiary to UMass on July 1, 2015, the Company granted UMass the right to require the Company to purchase all of its interest in the subsidiary at fair value commencing July 1, 2020. The subsidiary performs diagnostic information services in a defined territory within the state of Massachusetts. Since the redemption of the noncontrolling interest is outside of the Company's control, it has been presented outside of stockholders' equity at the greater of its carrying amount or its fair value. As of September 30, 2025 and December 31, 2024, the redeemable noncontrolling interest was presented at its fair value. For further details regarding the fair value of the redeemable noncontrolling interest, see Note 6.
v3.25.3
SUPPLEMENTAL CASH FLOW & OTHER DATA
 9 Months Ended
Sep. 30, 2025
Supplemental Cash Flow Elements [Abstract]  
SUPPLEMENTAL CASH FLOW & OTHER DATA SUPPLEMENTAL CASH FLOW AND OTHER DATA
    Supplemental cash flow and other data for the three and nine months ended September 30, 2025 and 2024 was as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Depreciation expense$103 $93 $308 $268 
Amortization expense39 32 117 90 
Depreciation and amortization expense$142 $125 $425 $358 
Interest expense$(69)$(58)$(210)$(154)
Interest income3 9 10 18 
Interest expense, net$(66)$(49)$(200)$(136)
Interest paid$22 $62 $167 $167 
Income taxes paid$2 $61 $112 $179 
Accounts payable associated with capital expenditures$40 $35 $40 $35 
Dividends payable$91 $84 $91 $84 
Businesses acquired:    
Fair value of assets acquired$34 $1,725 $57 $2,014 
Fair value of liabilities assumed— 142 6 183 
Fair value of net assets acquired34 1,583 51 1,831 
Merger consideration payable— — — — 
Cash paid for business acquisitions34 1,583 51 1,831 
Less: Cash acquired— 50 — 50 
Business acquisitions, net of cash acquired$34 $1,533 $51 $1,781 
Leases:
Leased assets obtained in exchange for new operating lease liabilities$44 $33 $140 $120 
    During the nine months ended September 30, 2025 and 2024, other financing activities, net in the Company's consolidated statement of cash flows included changes in bank overdrafts, which are generally settled in cash in the short term, of $(61) million and $(22) million, respectively.

    During the nine months ended September 30, 2025, the Company received $46 million from a payroll tax credit under the Coronavirus Aid, Relief, and Economic Security Act associated with the retention of employees. Such amount is recorded in other operating expense, net in the Company's consolidated statement of operations.
v3.25.3
COMMITMENTS AND CONTINGENCIES
 9 Months Ended
Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]  
COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES
    Letters of Credit

    The Company can issue letters of credit under its Secured Receivables Credit Facility and Senior Unsecured Revolving Credit Facility. For further discussion regarding the facilities, see Note 7 above and Note 13 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10-K.
    
    In support of its risk management program, $78 million in letters of credit under the Secured Receivables Credit Facility were outstanding as of September 30, 2025, providing collateral for current and future automobile liability and workers’ compensation loss payments.

    Contingent Lease Obligations
    
    The Company remains subject to contingent obligations under certain real estate leases for which no liability has been recorded. For further details, see Note 18 to the audited consolidated financial statements in the Company’s 2024 Annual Report on Form 10-K.

    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. After discovery was completed, the Company filed a motion for summary judgment, which was granted. The matter is on appeal.

    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 and class certification proceedings are ongoing.

    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.

    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 ("CIPA") and the California Confidentiality of Medical Information Act ("CMIA"). 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 refiled its motion to dismiss with the New Jersey District Court. The motion to dismiss was granted without prejudice as to the CMIA claim and denied as to the CIPA claim. Thereafter, the Company filed a motion for reconsideration as to the CIPA claim, which was granted. The matter is on appeal.

    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, which the Company has moved to dismiss. On August 23, 2024, the district court dismissed the complaint with prejudice. On appeal, the Eleventh Circuit affirmed the district court's dismissal.

    The Company also received subpoenas from the U.S. Attorney for the District of New Jersey (the “NJ USAO”). The subpoenas seek various records relating to the Company’s relationship with the New York Giants ("the Giants") and adherence to certain company policies and federal laws. The Company is in the process of finalizing a settlement with the NJ USAO and is negotiating a resolution with the United States Department of Health and Human Services. The Company has also received a subpoena from the New York Attorney General’s Office.

    The Company has also received subpoenas from the New York Attorney General’s Office that seek information about, among other things, the ordering and billing of certain test panels to Medicaid programs in New York. 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 September 30, 2025, the Company does not believe that material losses related to legal matters are probable.

    Reserves for legal matters totaled $21 million and $4 million as of September 30, 2025 and December 31, 2024, 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.

    The Company is subject to a series of individual claims brought by persons in Ireland related to allegations stemming from pap smear screening services performed by the Company. In general, claimants have alleged that the results of certain pap smear screening tests performed by the Company and other providers, pursuant to a program coordinated by the Irish government, were incorrect for individuals who were later diagnosed with cervical cancer. The Irish government and an independent scoping inquiry commissioned by the Irish government found that the Company’s performance of its screening services for the Irish cervical cancer screening program were in accordance with both Ireland’s requirements and international standards. The Company has settled claims made by certain individuals, is a party in multiple lawsuits and may be served as a party in additional lawsuits. The Company does not believe that the resolution of existing or future claims will have a material adverse effect on its financial position or liquidity, but the ultimate outcomes of these claims are unpredictable and subject to significant uncertainties.

    Reserves for general and professional liability claims 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 $169 million as of both September 30, 2025 and December 31, 2024.

    While the basis for claims reserves is actuarially determined losses based upon the Company's historical and projected loss experience, the process of analyzing, assessing and establishing reserve estimates relative to these types of claims involves a high degree of judgment. Although the Company believes that its present reserves and insurance coverage are sufficient to cover currently estimated exposures, it is possible that the Company may incur liabilities in excess of its recorded reserves or insurance coverage. Changes in the facts and circumstances associated with claims could have a material impact on the Company’s results of operations (principally costs of services), cash flows and financial condition in the period that reserve estimates are adjusted or paid.
v3.25.3
BUSINESS SEGMENT INFORMATION
 9 Months Ended
Sep. 30, 2025
Segment Reporting [Abstract]  
BUSINESS SEGMENT INFORMATION BUSINESS SEGMENT INFORMATION
    The Company's DIS business is the only reportable segment based on the manner in which the Chief Executive Officer, who is the Company's Chief Operating Decision Maker ("CODM"), assesses performance and allocates resources across the organization. The CODM uses the reported measurement of segment profit (loss) in assessing segment performance versus budget and when deciding how to allocate resources to segments. The DIS business provides diagnostic information services to a broad range of customers within its primary customer channels - physicians, hospitals, and patients and consumers. The DIS business accounted for greater than 97% of net revenues in both 2025 and 2024.

    All other operating segments include the Company's DS businesses, which consist of its risk assessment services and healthcare information technology businesses. The Company's DS businesses offer solutions for insurers and offer solutions for healthcare providers and payers.
        
    As of September 30, 2025, substantially all of the Company’s services were provided within the United States, and substantially all of the Company’s assets were located within the United States. See Note 6 to the audited consolidated financial statements contained in the Company’s 2024 Annual Report on Form 10-K for a discussion of the Company's acquisition of LifeLabs in Canada during August 2024.

    The following table is a summary of segment information for the three and nine months ended September 30, 2025 and 2024. Segment asset information is not presented since it is not received by the CODM at the operating segment level. The CODM regularly reviews certain consolidated expenses, including employee compensation costs. "Other segment items" principally consist of costs for obtaining, transporting and testing specimens, facility costs used for the delivery of the Company's services, costs associated with the Company's sales and marketing efforts, and costs related to billing operations. Operating income (loss) of each segment represents net revenues less directly identifiable expenses. General corporate activities included in the table below are comprised of general management and administrative corporate expenses, amortization and impairment of intangibles assets and other operating income and expenses, net of certain general corporate activity costs that are allocated to the DIS and DS businesses. The accounting policies of the segments are the same as those of the Company as set forth in Note 2 to the audited consolidated financial statements contained in the Company’s 2024 Annual Report on Form 10-K and Note 2 to the interim unaudited consolidated financial statements.
Three Months Ended
Nine Months Ended
September 30, 2025September 30, 2025
DISTotalDISTotal
Net revenues$2,755 $2,755 $8,043 $8,043 
DS revenues61 186 
Total net revenues$2,816 $8,229 
Less: Other segment items2,273 6,653 
Segment operating income$482 $482 $1,390 $1,390 
DS operating income9 24 
General corporate activities(105)(244)
Total operating income386 1,170 
Non-operating expense, net(58)(182)
Income before income taxes and equity in earnings of equity method investees328 988 
Income tax expense(77)(233)
Equity in earnings of equity method investees, net of taxes8 35 
Net income259 790 
Less: Net income attributable to noncontrolling interests14 43 
Net income attributable to Quest Diagnostics$245 $747 
Three Months EndedNine Months Ended
September 30, 2024September 30, 2024
DISTotalDISTotal
Net revenues$2,427 $2,427 $7,058 $7,058 
DS revenues61 193 
Total net revenues$2,488 $7,251 
Less: Other segment items2,020 5,858 
Segment operating income$407 $407 $1,200 $1,200 
DS operating income6 23 
General corporate activities(83)(238)
Total operating income330 985 
Non-operating expense, net(34)(109)
Income before income taxes and equity in earnings of equity method investees296 876 
Income tax expense(65)(205)
Equity in earnings of equity method investees, net of taxes6 14 
Net income237685
Less: Net income attributable to noncontrolling interests1136
Net income attributable to Quest Diagnostics$226 $649 
    
    Depreciation and amortization expense for the three and nine months ended September 30, 2025 and 2024 was as follows:
    
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
DIS business$99 $90 $296 $258 
All other operating segments3 3 10 9 
General corporate40 32 119 91 
Total depreciation and amortization$142 $125 $425 $358 
v3.25.3
REVENUE RECOGNITION
 9 Months Ended
Sep. 30, 2025
Revenue from Contract with Customer [Abstract]  
REVENUE RECOGITION REVENUE RECOGNITION
    DIS

    Net revenues in the Company’s DIS business accounted for over 97% of the Company’s total net revenues for the three and nine months ended September 30, 2025 and 2024 and are primarily comprised of a high volume of relatively low-dollar transactions. The DIS business, which provides clinical testing services and other services, satisfies its performance obligations and recognizes revenues primarily upon completion of the testing process (when results are reported) or when services have been rendered. The Company estimates the amount of consideration it expects to be entitled to receive from payer customer groups in exchange for providing services using the portfolio approach. These estimates include the impact of contractual allowances (including payer denials), and patient price concessions. The portfolios determined using the portfolio approach consist of the following groups of payer customers: healthcare insurers, government payers (including Medicare and Medicaid programs), client payers and patients.
    For further details regarding revenue recognition in the Company's DIS business, see Note 3 to the audited consolidated financial statements in the Company's 2024 Annual Report on Form 10-K.

    DS

    The Company’s DS businesses primarily satisfy their performance obligations and recognize revenues when delivery has occurred or services have been rendered.

    Net Revenue and Net Accounts Receivable by Payer Customer Type

    The approximate percentage of net revenue by type of payer customer was as follows:
    
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Healthcare insurers:
Fee-for-service37 %38 %36 %37 %
Capitated2 3 3 3 
Total healthcare insurers39 41 39 40 
Government payers (principally fee-for-service)16 13 16 12 
Client payers31 33 31 33 
Patients (including coinsurance and deductible responsibilities)12 10 12 12 
Total DIS98 97 98 97 
DS2 3 2 3 
Net revenues100 %100 %100 %100 %
    
    The approximate percentage of net accounts receivable by type of payer customer was as follows:
September 30, 2025December 31, 2024
Healthcare Insurers29 %26 %
Government Payers9 7 
Client Payers41 45 
Patients (including coinsurance and deductible responsibilities)19 20 
Total DIS98 98 
DS2 2 
Net accounts receivable100 %100 %
v3.25.3
Insider Trading Arrangements
 3 Months Ended
Sep. 30, 2025
shares
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement During the quarterly period covered by this report, our directors and officers (as defined in Rule 16a-1(f) of the Securities Exchange Act of 1934, as amended) adopted, terminated or modified the Rule 10b5-1 trading arrangements (as defined in Item 408 of Regulation S-K) set forth in the table below. No non-Rule 10b5-1 trading arrangements were adopted, modified or terminated by any director or officer during the quarterly period covered by this report.
    
NameTitleType of Trading ArrangementSecurityActionDate of ActionDuration of Trading ArrangementAggregate Number of Securities Covered
Jim DavisChairman, CEO, and PresidentRule 10b5-1 plan to sellCommon StockAdoptionAugust 26, 2025
August 26, 2025 to December 4, 2026*
Up to 95,093*
Mark DelaneySVP and Chief Commercial OfficerRule 10b5-1 plan to sellCommon StockAdoptionAugust 18, 2025
August 18, 2025 to May 11, 2026*
Up to 7,946*

    * Includes shares of common stock to be released from: (a) stock options and/or restricted stock units that are expected to vest and/or (b) performance share awards that may vest, subject to the satisfaction of the applicable performance metrics. The actual number of shares of common stock that will be released is not yet determinable and the actual number of shares of common stock that will be sold will be net of the number of shares withheld to satisfy employee tax withholding obligations.
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
Jim Davis [Member]  
Trading Arrangements, by Individual  
Name Jim Davis
Title Chairman, CEO, and President
Rule 10b5-1 Arrangement Adopted true
Adoption Date August 26, 2025
Expiration Date December 4, 2026
Arrangement Duration 465 days
Aggregate Available 95,093
Mark Delaney [Member]  
Trading Arrangements, by Individual  
Name Mark Delaney
Title SVP and Chief Commercial Officer
Rule 10b5-1 Arrangement Adopted true
Adoption Date August 18, 2025
Expiration Date May 11, 2026
Arrangement Duration 266 days
Aggregate Available 7,946
v3.25.3
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)
 9 Months Ended
Sep. 30, 2025
Accounting Policies [Abstract]  
Basis of Presentation The interim unaudited consolidated financial statements reflect all adjustments which in the opinion of management are necessary for a fair statement of results of operations, comprehensive income, financial condition, cash flows and stockholders' equity for the periods presented. Except as otherwise disclosed, all such adjustments are of a normal recurring nature. Operating results for the interim periods are not necessarily indicative of the results that may be expected for the full year. These interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in the Company’s 2024 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2024 but does not include all the disclosures required by accounting principles generally accepted in the United States (“GAAP”).
Use Of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Earnings Per Share The Company's unvested restricted stock units that contain non-forfeitable rights to dividends are participating securities and, therefore, are included in the earnings allocation in computing earnings per share using the two-class method. Basic earnings per common share is calculated by dividing net income attributable to Quest Diagnostics, adjusted for earnings allocated to participating securities, by the weighted average number of common shares outstanding. Diluted earnings per common share is calculated by dividing net income attributable to Quest Diagnostics, adjusted for earnings allocated to
participating securities, by the weighted average number of common shares outstanding after giving effect to all potentially dilutive common shares outstanding during the period. Potentially dilutive common shares include the dilutive effect of outstanding stock options and performance share units granted under the Company's Amended and Restated Employee Long-Term Incentive Plan (“ELTIP”) and its Amended and Restated Non-Employee Director Long-Term Incentive Plan (“DLTIP”), as well as the dilutive effect of accelerated share repurchase agreements, if applicable. Earnings allocable to participating securities include the portion of dividends declared as well as the portion of undistributed earnings during the period allocable to participating securities.
New Accounting Standards to be Adopted In December 2023, the Financial Accounting Standards Board ("FASB") issued a new accounting standard which will require companies to make additional income tax disclosures. The pronouncement is effective for annual filings for the year ended December 31, 2025. The Company does not expect the adoption of this standard to have a material impact on its results of operations, financial position or cash flows.
    In November 2024, the FASB issued a new accounting standard which will require companies to disaggregate certain income statement expenses. The pronouncement is effective for annual filings for the year ended December 31, 2027 and for interim periods within the year ended December 31, 2028. The Company does not expect the adoption of this standard to have a material impact on its results of operations, financial position or cash flows.

    In September 2025, the FASB issued a new accounting standard which impacts internal-use software accounting by removing all references to software development project stages such that the guidance is neutral to different software development methods. The pronouncement is effective for annual filings for the year ended December 31, 2028 and for interim periods within such year. The Company is currently evaluating the impact of the standard.

    In July 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted. The OBBBA makes permanent key elements of the Tax Cuts and Jobs Act of 2017, including 100% bonus depreciation, domestic research cost expensing and the business interest expense limitation, among other tax changes. Many of the tax provisions of the OBBBA are designed to accelerate tax deductions, which could lead to lower cash tax payments. The new legislation has multiple effective dates, with certain provisions effective in 2025 and others in the future. While the Company continues to assess the impact of the tax provisions of the OBBBA on its consolidated financial statements, the Company currently believes that the tax provisions of the legislation are not expected to have a material impact on the Company’s statement of operations. The Company's consolidated deferred income tax liabilities as of September 30, 2025 and December 31, 2024 were $378 million and $278 million, respectively. The increase was principally due to the domestic research cost expensing and bonus depreciation elements of the OBBBA.
Derivative Financial Instruments The Company uses derivative financial instruments, from time to time, to manage its exposure to market risks for changes in interest rates and foreign currencies. This strategy includes the use of interest rate swap agreements, forward-starting interest rate swap agreements, interest rate lock agreements and foreign currency forward contracts to manage its exposure to movements in interest and currency rates. The Company has established policies and procedures for risk assessment and the approval, reporting and monitoring of derivative financial instrument activities. These policies prohibit holding or issuing derivative financial instruments for speculative purposes. The Company does not enter into derivative financial instruments that contain credit-risk-related contingent features or requirements to post collateral.
    Interest Rate Risk
    
    The Company is exposed to interest rate risk on its cash and cash equivalents and its debt obligations. Interest income earned on cash and cash equivalents may fluctuate as interest rates change; however, due to their relatively short maturities, the Company does not hedge these assets or their investment cash flows and the impact of interest rate risk is not material. The Company's debt obligations consist of fixed-rate and, from time to time, variable-rate debt instruments. The Company's primary objective is to achieve the lowest overall cost of funding while managing the variability in cash outflows within an acceptable range. In order to achieve this objective, the Company has historically entered into interest rate swap agreements.

    Interest rate swaps involve the periodic exchange of payments without the exchange of underlying principal or notional amounts. Net settlements between the counterparties are recognized as an adjustment to interest expense, net.
v3.25.3
EARNINGS PER SHARE (Tables)
 9 Months Ended
Sep. 30, 2025
Earnings Per Share [Abstract]  
Schedule of Earnings Per Share, Basic and Diluted The computation of basic and diluted earnings per common share was as follows (in millions, except per share data):
Three Months Ended September 30,Nine Months Ended September 30,
 2025202420252024
Amounts attributable to Quest Diagnostics’ common stockholders:    
Net income attributable to Quest Diagnostics$245 $226 $747 $649 
Less: Earnings allocated to participating securities2 1 4 3 
Earnings available to Quest Diagnostics’ common stockholders – basic and diluted
$243 $225 $743 $646 
Weighted average common shares outstanding – basic112 112 112 111 
Effect of dilutive securities:    
Stock options and performance share units1 1 1 1 
Weighted average common shares outstanding – diluted113 113 113 112 
Earnings per share attributable to Quest Diagnostics’ common stockholders:    
Basic$2.18 $2.01 $6.66 $5.80 
Diluted$2.16 $1.99 $6.57 $5.74 
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share The following securities were not included in the calculation of diluted earnings per share due to their antidilutive effect:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Stock options and performance share units— — — 1 
v3.25.3
RESTRUCTURING ACTIVITIES AND IMPAIRMENT CHARGES (Tables)
 9 Months Ended
Sep. 30, 2025
Restructuring and Related Activities [Abstract]  
Schedule of Pre-Tax Restructuring and Impairment Charges The following table provides a summary of the Company's pre-tax restructuring and impairment charges for the three and nine months ended September 30, 2025 and 2024:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Employee separation costs$6 $7 $18 $21 
Asset impairment charges5 — 29 — 
Total restructuring and impairment charges$11 $7 $47 $21 
v3.25.3
BUSINESS ACQUISITIONS (Tables)
 9 Months Ended
Sep. 30, 2024
Business Combination [Abstract]  
Business Combination, Pro Forma Information The following unaudited pro forma combined financial information reflects the consolidated statement of operations of the Company as if the acquisition of LifeLabs had occurred as of January 1, 2023. The pro forma information includes adjustments primarily related to the amortization of acquired intangible assets, interest expense associated with debt of LifeLabs which was extinguished prior to the acquisition, interest expense associated with senior notes issued to fund the acquisition, the impact on depreciation expense of recording acquired property, plant and equipment at fair value, and transaction costs related to the LifeLabs acquisition. The pro forma combined financial information does not include the estimated annual synergies expected to be realized upon completion of the integration of LifeLabs and therefore is not indicative of the results of operations as they would have been had the transaction been effected on the assumed date (in millions, except per share data).
Three Months Ended September 30, 2024Nine Months Ended September 30, 2024
Pro forma net revenues$2,588 $7,700 
Pro forma net income attributable to Quest Diagnostics$222 $647 
Pro forma earnings per share attributable to Quest Diagnostics' common stockholders:
Basic$1.97 $5.78 
Diluted$1.95 $5.72 
    
    Acquisition of select assets of Spectra Laboratories
v3.25.3
FAIR VALUE MEASUREMENTS (Tables)
 9 Months Ended
Sep. 30, 2025
Fair Value Disclosures [Abstract]  
Fair Value, Measurement Inputs The following table provides a summary of the recognized assets and liabilities that are measured at fair value on a recurring basis:
Basis of Fair Value Measurements
Quoted Prices in Active Markets for Identical Assets/LiabilitiesSignificant Other Observable InputsSignificant Unobservable Inputs
September 30, 2025TotalLevel 1Level 2Level 3
Assets:    
Deferred compensation trading securities$82 $82 $— $— 
Cash surrender value of life insurance policies72 — 72 — 
Equity investments3 3 — — 
Fixed-to-variable interest rate swaps18 — 18 — 
Total$175 $85 $90 $— 
Liabilities:    
Deferred compensation liabilities$152 $— $152 $— 
Contingent consideration114 — — 114 
Total$266 $— $152 $114 
Redeemable noncontrolling interest$81 $— $— $81 
Basis of Fair Value Measurements
December 31, 2024TotalLevel 1Level 2Level 3
Assets:       
Deferred compensation trading securities$72 $72 $— $— 
Cash surrender value of life insurance policies64 — 64 — 
Total$136 $72 $64 $— 
Liabilities:    
Deferred compensation liabilities$140 $— $140 $— 
Contingent consideration106 — — 106 
Fixed-to-variable interest rate swaps34 — 34 — 
Total$280 $— $174 $106 
Redeemable noncontrolling interest$83 $— $— $83 
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation The following table provides a reconciliation of the beginning and ending balances of liabilities using significant unobservable inputs (Level 3):
Contingent Consideration
Balance, December 31, 2024
$106 
Total fair value adjustments included in earnings - unrealized8 
Balance, September 30, 2025$114 
v3.25.3
FINANCIAL INSTRUMENTS (Tables)
 9 Months Ended
Sep. 30, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Derivative Instruments A summary of the notional amounts of these interest rate swap agreements as of September 30, 2025 and December 31, 2024 was as follows:
Notional Amount
Debt InstrumentSeptember 30, 2025December 31, 2024
5.00% Senior Notes due December 2034
$850 $700 
2.80% Senior Notes due June 2031
550 — 
6.40% Senior Notes due November 2033
400 — 
Total notional amounts$1,800 $700 
Schedule of Debt Instrument Fair Value Basis Adjustment Attributable to Hedged Debt As of September 30, 2025 and December 31, 2024, the following amounts were recorded on the consolidated balance sheets related to cumulative basis adjustments for fair value hedges included in the carrying amount of long-term debt:
Carrying Amount of Hedged Long-Term DebtHedge Accounting Basis Adjustment (a)Carrying Amount of Hedged Long-Term DebtHedge Accounting Basis Adjustment (a)
Balance Sheet ClassificationSeptember 30, 2025September 30, 2025December 31, 2024December 31, 2024
Long-term debt$1,803 $20 $658 $(29)

(a) The balance includes $2 million and $5 million of remaining unamortized hedging adjustments on discontinued relationships as of September 30, 2025 and December 31, 2024, respectively.
Schedule of Fair Value Hedge Accounting on the Statement of Operations The following table presents the effect of fair value hedge accounting on the consolidated statement of operations for the three and nine months ended September 30, 2025:
Three Months Ended
September 30, 2025
Nine Months Ended September 30, 2025
Interest Expense, NetInterest Expense, Net
Total for line item in which the effects of fair value hedges are recorded$(66)$(200)
Gain (loss) on fair value hedging relationships:
Hedged items (Long-term debt)$(1)$(52)
Derivatives designated as hedging instruments$1 $52 
Schedule of Derivative Instruments at Fair Value A summary of the fair values of derivative instruments in the consolidated balance sheets was as follows:
September 30, 2025December 31, 2024
Balance Sheet
Classification		Fair ValueBalance Sheet
Classification		Fair Value
Derivatives Designated as Hedging Instruments   
Fixed-to-variable interest rate swap agreementsOther assets$18 Other liabilities$34 
v3.25.3
STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST (Tables)
 9 Months Ended
Sep. 30, 2025
Equity [Abstract]  
Components of Accumulated Other Comprehensive Income (Loss) The changes in accumulated other comprehensive loss by component for the three and nine months ended September 30, 2025 were as follows:
For the Three Months Ended September 30, 2025Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, June 30, 2025$(21)$5 $(16)
Other comprehensive loss before reclassifications(24)— (24)
Net current period other comprehensive loss(24)— (24)
Balance, September 30, 2025$(45)$5 $(40)
For the Nine Months Ended September 30, 2025Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, December 31, 2024$(93)$5 $(88)
Other comprehensive income before reclassifications48 — 48 
Net current period other comprehensive income48 — 48 
Balance, September 30, 2025$(45)$5 $(40)
    The changes in accumulated other comprehensive loss by component for the three and nine months ended September 30, 2024 were as follows:
For the Three Months Ended September 30, 2024Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, June 30, 2024$(22)$3 $(19)
Other comprehensive income before reclassifications1 3 4 
Net current period other comprehensive income1 3 4 
Balance, September 30, 2024$(21)$6 $(15)
For the Nine Months Ended September 30, 2024Foreign
Currency
Translation
Adjustments		Net Deferred Gains on Cash Flow Hedges, net of taxAccumulated Other Comprehensive Loss
Balance, December 31, 2023$(17)$3 $(14)
Other comprehensive (loss) income before reclassifications(4)3 (1)
Net current period other comprehensive (loss) income(4)3 (1)
Balance, September 30, 2024$(21)$6 $(15)
v3.25.3
SUPPLEMENTAL CASH FLOW & OTHER DATA (Tables)
 9 Months Ended
Sep. 30, 2025
Supplemental Cash Flow Elements [Abstract]  
Supplemental Cash Flow and Other Data Supplemental cash flow and other data for the three and nine months ended September 30, 2025 and 2024 was as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Depreciation expense$103 $93 $308 $268 
Amortization expense39 32 117 90 
Depreciation and amortization expense$142 $125 $425 $358 
Interest expense$(69)$(58)$(210)$(154)
Interest income3 9 10 18 
Interest expense, net$(66)$(49)$(200)$(136)
Interest paid$22 $62 $167 $167 
Income taxes paid$2 $61 $112 $179 
Accounts payable associated with capital expenditures$40 $35 $40 $35 
Dividends payable$91 $84 $91 $84 
Businesses acquired:    
Fair value of assets acquired$34 $1,725 $57 $2,014 
Fair value of liabilities assumed— 142 6 183 
Fair value of net assets acquired34 1,583 51 1,831 
Merger consideration payable— — — — 
Cash paid for business acquisitions34 1,583 51 1,831 
Less: Cash acquired— 50 — 50 
Business acquisitions, net of cash acquired$34 $1,533 $51 $1,781 
Leases:
Leased assets obtained in exchange for new operating lease liabilities$44 $33 $140 $120 
v3.25.3
BUSINESS SEGMENT INFORMATION (Tables)
 9 Months Ended
Sep. 30, 2025
Segment Reporting [Abstract]  
Summary of Segment Reporting Information by Segment The following table is a summary of segment information for the three and nine months ended September 30, 2025 and 2024. Segment asset information is not presented since it is not received by the CODM at the operating segment level. The CODM regularly reviews certain consolidated expenses, including employee compensation costs. "Other segment items" principally consist of costs for obtaining, transporting and testing specimens, facility costs used for the delivery of the Company's services, costs associated with the Company's sales and marketing efforts, and costs related to billing operations. Operating income (loss) of each segment represents net revenues less directly identifiable expenses. General corporate activities included in the table below are comprised of general management and administrative corporate expenses, amortization and impairment of intangibles assets and other operating income and expenses, net of certain general corporate activity costs that are allocated to the DIS and DS businesses. The accounting policies of the segments are the same as those of the Company as set forth in Note 2 to the audited consolidated financial statements contained in the Company’s 2024 Annual Report on Form 10-K and Note 2 to the interim unaudited consolidated financial statements.
Three Months Ended
Nine Months Ended
September 30, 2025September 30, 2025
DISTotalDISTotal
Net revenues$2,755 $2,755 $8,043 $8,043 
DS revenues61 186 
Total net revenues$2,816 $8,229 
Less: Other segment items2,273 6,653 
Segment operating income$482 $482 $1,390 $1,390 
DS operating income9 24 
General corporate activities(105)(244)
Total operating income386 1,170 
Non-operating expense, net(58)(182)
Income before income taxes and equity in earnings of equity method investees328 988 
Income tax expense(77)(233)
Equity in earnings of equity method investees, net of taxes8 35 
Net income259 790 
Less: Net income attributable to noncontrolling interests14 43 
Net income attributable to Quest Diagnostics$245 $747 
Three Months EndedNine Months Ended
September 30, 2024September 30, 2024
DISTotalDISTotal
Net revenues$2,427 $2,427 $7,058 $7,058 
DS revenues61 193 
Total net revenues$2,488 $7,251 
Less: Other segment items2,020 5,858 
Segment operating income$407 $407 $1,200 $1,200 
DS operating income6 23 
General corporate activities(83)(238)
Total operating income330 985 
Non-operating expense, net(34)(109)
Income before income taxes and equity in earnings of equity method investees296 876 
Income tax expense(65)(205)
Equity in earnings of equity method investees, net of taxes6 14 
Net income237685
Less: Net income attributable to noncontrolling interests1136
Net income attributable to Quest Diagnostics$226 $649 
    
    Depreciation and amortization expense for the three and nine months ended September 30, 2025 and 2024 was as follows:
    
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
DIS business$99 $90 $296 $258 
All other operating segments3 3 10 9 
General corporate40 32 119 91 
Total depreciation and amortization$142 $125 $425 $358 
v3.25.3
REVENUE RECOGNITION (Tables)
 9 Months Ended
Sep. 30, 2025
Revenue from Contract with Customer [Abstract]  
Disaggregation of Revenue The approximate percentage of net revenue by type of payer customer was as follows:
    
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Healthcare insurers:
Fee-for-service37 %38 %36 %37 %
Capitated2 3 3 3 
Total healthcare insurers39 41 39 40 
Government payers (principally fee-for-service)16 13 16 12 
Client payers31 33 31 33 
Patients (including coinsurance and deductible responsibilities)12 10 12 12 
Total DIS98 97 98 97 
DS2 3 2 3 
Net revenues100 %100 %100 %100 %
Accounts Receivable Disaggregation The approximate percentage of net accounts receivable by type of payer customer was as follows:
September 30, 2025December 31, 2024
Healthcare Insurers29 %26 %
Government Payers9 7 
Client Payers41 45 
Patients (including coinsurance and deductible responsibilities)19 20 
Total DIS98 98 
DS2 2 
Net accounts receivable100 %100 %
v3.25.3
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Other Liabilities    
Accounting Policies [Line Items]    
Deferred income tax liabilities $ 378 $ 278
v3.25.3
EARNINGS PER SHARE (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Amounts attributable to Quest Diagnostics’ common stockholders:        
Net income attributable to Quest Diagnostics $ 245 $ 226 $ 747 $ 649
Less: Earnings allocated to participating securities 2 1 4 3
Earnings available to Quest Diagnostics’ common stockholders – basic and diluted $ 243 $ 225 $ 743 $ 646
Weighted average common shares outstanding - basic 112 112 112 111
Stock options and performance share units 1 1 1 1
Weighted average common shares outstanding - diluted 113 113 113 112
Basic (in dollars per share) $ 2.18 $ 2.01 $ 6.66 $ 5.80
Diluted (in dollars per share) $ 2.16 $ 1.99 $ 6.57 $ 5.74
Stock options and performance share units (in shares) 0 0 0 1
v3.25.3
RESTRUCTURING ACTIVITIES AND IMPAIRMENT CHARGES - Additional Information (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Restructuring Cost and Reserve [Line Items]          
Asset impairment charges $ 5 $ 0 $ 29 $ 0  
Total restructuring and impairment charges 11 7 47 21  
Total restructuring charges $ 6 7 $ 18 21  
Invigorate Program          
Restructuring Cost and Reserve [Line Items]          
Target percent for annual productivity savings 3.00%   3.00%    
Pre-tax restructuring charges $ 6 7 $ 18 21  
Invigorate Program | Accounts Payable and Accrued Expenses          
Restructuring Cost and Reserve [Line Items]          
Restructuring reserve 14   14   $ 13
Invigorate Program | Cost of services          
Restructuring Cost and Reserve [Line Items]          
Total restructuring and impairment charges 2   8    
Total restructuring charges   4   12  
Invigorate Program | Selling, general and administrative          
Restructuring Cost and Reserve [Line Items]          
Total restructuring and impairment charges 4   10    
Total restructuring charges   $ 3   $ 9  
Invigorate Program | Other Operating Income, net          
Restructuring Cost and Reserve [Line Items]          
Total restructuring and impairment charges $ 5   $ 29    
v3.25.3
RESTRUCTURING ACTIVITIES AND IMPAIRMENT CHARGES - Pre-Tax Restructuring and Impairment Charges (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Restructuring and Related Activities [Abstract]        
Employee separation costs $ 6 $ 7 $ 18 $ 21
Asset impairment charges 5 0 29 0
Total restructuring and impairment charges $ 11 $ 7 $ 47 $ 21
v3.25.3
BUSINESS ACQUISITIONS - Additional Information (Details)
$ in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Aug. 04, 2025
USD ($)
Aug. 23, 2024
CAD ($)
Aug. 23, 2024
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Aug. 31, 2025
Business Combination [Line Items]                
Cash paid for business acquisitions       $ 34 $ 1,583 $ 51 $ 1,831  
Corewell Health                
Business Combination [Line Items]                
Subsidiary, ownership percentage, parent               51.00%
Laboratory Facility | Corewell Health                
Business Combination [Line Items]                
Ownership percentage               49.00%
LifeLabs Inc.                
Business Combination [Line Items]                
Cash paid for business acquisitions   $ 1,350 $ 1,000          
Deferred tax asset, increase           9    
Goodwill, decrease           $ 9    
Spectra Laboratories                
Business Combination [Line Items]                
Cash paid for business acquisitions $ 34              
Goodwill, expected tax deductible amount 25              
Spectra Laboratories | Customer Relationships                
Business Combination [Line Items]                
Intangible assets $ 9              
Intangible assets, useful life 15 years              
v3.25.3
BUSINESS ACQUISITIONS - Pro Forma (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2024
Business Combination [Abstract]    
Pro forma net revenues $ 2,588 $ 7,700
Pro forma net income attributable to Quest Diagnostics $ 222 $ 647
Pro forma earnings per share attributable to Quest Diagnostics' common stockholders:    
Basic (in dollars per share) $ 1.97 $ 5.78
Diluted (in dollars per share) $ 1.95 $ 5.72
v3.25.3
FAIR VALUE MEASUREMENTS - Recognized Assets and Liabilities at Fair Value) (Details) - Recurring Basis - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Deferred compensation trading securities $ 82 $ 72
Cash surrender value of life insurance policies 72 64
Equity investments 3  
Fixed-to-variable interest rate swaps 18  
Total 175 136
Deferred compensation liabilities 152 140
Contingent consideration 114 106
Fixed-to-variable interest rate swaps   34
Total 266 280
Redeemable noncontrolling interest 81 83
Quoted Prices in Active Markets for Identical Assets / Liabilities, Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Deferred compensation trading securities 82 72
Cash surrender value of life insurance policies 0 0
Equity investments 3  
Total 85 72
Deferred compensation liabilities 0 0
Contingent consideration 0 0
Fixed-to-variable interest rate swaps   0
Total 0 0
Redeemable noncontrolling interest 0 0
Significant Other Observable Inputs, Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Deferred compensation trading securities 0 0
Cash surrender value of life insurance policies 72 64
Equity investments 0  
Fixed-to-variable interest rate swaps 18  
Total 90 64
Deferred compensation liabilities 152 140
Contingent consideration 0 0
Fixed-to-variable interest rate swaps   34
Total 152 174
Significant Unobservable Inputs, Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Deferred compensation trading securities 0 0
Cash surrender value of life insurance policies 0 0
Equity investments 0  
Fixed-to-variable interest rate swaps 0  
Total 0 0
Deferred compensation liabilities 0 0
Contingent consideration 114 106
Fixed-to-variable interest rate swaps   0
Total 114 106
Redeemable noncontrolling interest $ 81 $ 83
v3.25.3
FAIR VALUE MEASUREMENTS - Additional Information (Details)
 3 Months Ended 9 Months Ended
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Jul. 01, 2015
Restructuring Cost and Reserve [Line Items]              
Asset impairment charges $ 5,000,000 $ 0 $ 29,000,000 $ 0      
Fair value of debt 5,700,000,000   5,700,000,000   $ 6,100,000,000    
UMass Joint Venture              
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]              
Ownership percentage by noncontrolling owners             18.90%
Fair Value, Inputs, Level 3 | Contingent Consideration              
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]              
Total fair value adjustments included in earnings - realized/unrealized     8,000,000        
Liability 114,000,000   114,000,000   106,000,000    
Fair Value, Inputs, Level 3 | Contingent Consideration | Other Liabilities              
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]              
Liability 63,000,000   63,000,000   101,000,000    
Fair Value, Inputs, Level 3 | Contingent Consideration | Accounts Payable and Accrued Expenses              
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]              
Liability $ 51,000,000   $ 51,000,000   $ 5,000,000    
Haystack Oncology, Inc. | Comparable Company Revenue Volatility              
Business Combination [Line Items]              
Measurement input 0.35   0.35        
Haystack Oncology, Inc. | Discount rate              
Business Combination [Line Items]              
Measurement input 0.105   0.105        
Haystack Oncology, Inc. | Additional, Based on Revenue              
Business Combination [Line Items]              
Maximum contingent consideration payment           $ 100,000,000  
Haystack Oncology, Inc. | Additional, Reimbursement Coverage              
Business Combination [Line Items]              
Maximum contingent consideration payment           $ 50,000,000  
Haystack Oncology, Inc. | Additional Impact | Discount rate              
Business Combination [Line Items]              
Measurement input 0.05   0.05        
Haystack Oncology, Inc. | Changing Comparable Company Revenue Volatility | Comparable Company Revenue Volatility              
Business Combination [Line Items]              
Measurement input 0.25   0.25        
Increase in contingent consideration liability     $ 4,000,000        
Haystack Oncology, Inc. | Changing Discount Rate | Discount rate              
Business Combination [Line Items]              
Measurement input 0.070   0.070        
Increase in contingent consideration liability     $ 2,000,000        
v3.25.3
FAIR VALUE MEASUREMENTS - Reconciliation of Beginning and Ending Balances of Assets and Liabilities Unobservable Inputs (Details) - Significant Unobservable Inputs, Level 3 - Contingent Consideration
$ in Millions
 9 Months Ended
Sep. 30, 2025
USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]  
Balance, December 31, 2024 $ 106
Total fair value adjustments included in earnings - unrealized 8
Balance, September 30, 2025 $ 114
v3.25.3
DEBT (Details) - USD ($)
 9 Months Ended
Sep. 30, 2025
Apr. 30, 2025
Mar. 30, 2025
Dec. 31, 2024
Senior Unsecured Revolving Credit Facility        
Debt Instrument [Line Items]        
Credit facility capacity   $ 750,000,000    
Interest rate 1.00%      
Line of credit facility, amount outstanding $ 0     $ 0
Senior Unsecured Revolving Credit Facility | If Uncommitted Accordion Is Utilized        
Debt Instrument [Line Items]        
Credit facility capacity   1,300,000,000    
Senior Unsecured Revolving Credit Facility | Uncommitted Accordion        
Debt Instrument [Line Items]        
Credit facility capacity   500,000,000    
Senior Unsecured Revolving Credit Facility | Letter of Credit        
Debt Instrument [Line Items]        
Credit facility capacity   $ 150,000,000    
Senior Notes | 3.50% Senior Notes Due March 2025        
Debt Instrument [Line Items]        
Face amount       $ 600,000,000
Extinguishment of debt 600,000,000      
Debt instrument, interest rate     3.50%  
Senior Notes | 3.45% Senior Notes due June 2026        
Debt Instrument [Line Items]        
Face amount $ 500,000,000      
Debt instrument, interest rate       3.45%
v3.25.3
FINANCIAL INSTRUMENTS - Additional Information (Details) - Fair Value Hedging - Interest Rate Swap
Sep. 30, 2025
Minimum  
Derivative [Line Items]  
Derivative, Basis Spread on Variable Rate 1.36%
Maximum  
Derivative [Line Items]  
Derivative, Basis Spread on Variable Rate 2.48%
v3.25.3
FINANCIAL INSTRUMENTS - Balance Sheets (Details) - Fair Value Hedging - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Derivative [Line Items]    
Carrying Amount of Hedged Long-Term Debt $ 1,803 $ 658
Hedge Accounting Basis Adjustment 20 (29)
Deferred (gain) loss on discontinuation of fair value hedge $ 2 $ 5
v3.25.3
FINANCIAL INSTRUMENTS - Income Statement (Details) - Fair Value Hedging - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2025
Derivative [Line Items]    
Hedged items (Long-term debt) $ (1) $ (52)
Derivatives designated as hedging instruments $ 1 $ 52
v3.25.3
FINANCIAL INSTRUMENTS - Summary of Notional Amounts (Details) - USD ($)
Sep. 30, 2025
Dec. 31, 2024
5.00% Senior Notes due December 2034 | Senior Notes    
Derivative [Line Items]    
Debt instrument, interest rate 5.00%  
2.80% Senior Notes due June 2031 | Senior Notes    
Derivative [Line Items]    
Debt instrument, interest rate 2.80%  
6.40% Senior Notes due November 2033 | Senior Notes    
Derivative [Line Items]    
Debt instrument, interest rate 6.40%  
Fair Value Hedging | Interest Rate Swaps    
Derivative [Line Items]    
Total notional amounts $ 1,800,000,000 $ 700,000,000
Fair Value Hedging | Interest Rate Swaps | 5.00% Senior Notes due December 2034    
Derivative [Line Items]    
Total notional amounts 850,000,000 700,000,000
Fair Value Hedging | Interest Rate Swaps | 2.80% Senior Notes due June 2031    
Derivative [Line Items]    
Total notional amounts 550,000,000 0
Fair Value Hedging | Interest Rate Swaps | 6.40% Senior Notes due November 2033    
Derivative [Line Items]    
Total notional amounts $ 400,000,000 $ 0
v3.25.3
FINANCIAL INSTRUMENTS - Fair Value of Derivatives (Details) - Designated as Hedging Instrument - Interest Rate Swaps - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Other Assets    
Derivatives, Fair Value [Line Items]    
Fixed-to-variable interest rate swap agreements $ 18  
Other Liabilities    
Derivatives, Fair Value [Line Items]    
Fixed-to-variable interest rate swap agreements   $ 34
v3.25.3
STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST - Components of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]        
Balance $ 7,265 $ 6,656 $ 6,813 $ 6,342
Net current period other comprehensive loss (24) 4 48 (1)
Balance 7,295 6,841 7,295 6,841
Foreign Currency Translation Adjustments        
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]        
Balance (21) (22) (93) (17)
Other comprehensive income (loss) before reclassifications (24) 1 48 (4)
Net current period other comprehensive loss (24) 1 48 (4)
Balance (45) (21) (45) (21)
Net Deferred Gains on Cash Flow Hedges, net of tax        
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]        
Balance 5 3 5 3
Other comprehensive income (loss) before reclassifications 0 3 0 3
Net current period other comprehensive loss 0 3 0 3
Balance 5 6 5 6
Accumulated Other Comprehensive Loss        
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]        
Balance (16) (19) (88) (14)
Other comprehensive income (loss) before reclassifications (24) 4 48 (1)
Net current period other comprehensive loss (24) 4 48 (1)
Balance $ (40) $ (15) $ (40) $ (15)
v3.25.3
STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Sep. 30, 2025
Sep. 30, 2024
Jul. 01, 2015
Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]                    
Dividends per common share $ 0.80 $ 0.80 $ 0.80 $ 0.75 $ 0.75 $ 0.75 $ 0.75      
Share repurchase authorization remaining available $ 700             $ 700    
Purchases of treasury stock 150             $ 150    
Reissuance of shares for employee benefit plan               1,200,000 1,000,000.0  
UMass Joint Venture                    
Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]                    
Ownership percentage by noncontrolling owners                   18.90%
Treasury Stock, at Cost                    
Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]                    
Purchases of treasury stock, shares               900,000 0  
Purchases of treasury stock $ 150             $ 150    
v3.25.3
SUPPLEMENTAL CASH FLOW & OTHER DATA (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Supplemental Cash Flow Elements [Abstract]        
Depreciation expense $ 103 $ 93 $ 308 $ 268
Amortization expense 39 32 117 90
Depreciation and amortization expense 142 125 425 358
Interest expense (69) (58) (210) (154)
Interest income 3 9 10 18
Interest expense, net (66) (49) (200) (136)
Interest paid 22 62 167 167
Income taxes paid 2 61 112 179
Accounts payable associated with capital expenditures 40 35 40 35
Dividends payable 91 84 91 84
Fair value of assets acquired 34 1,725 57 2,014
Fair value of liabilities assumed 0 142 6 183
Fair value of net assets acquired 34 1,583 51 1,831
Merger consideration payable 0 0 0 0
Cash paid for business acquisitions 34 1,583 51 1,831
Less: Cash acquired 0 50 0 50
Business acquisitions, net of cash acquired 34 1,533 51 1,781
Leases:        
Leased assets obtained in exchange for new operating lease liabilities $ 44 $ 33 140 120
Changes in bank overdrafts     (61) $ (22)
Payroll tax credit, CARES Act     $ 46  
v3.25.3
COMMITMENTS AND CONTINGENCIES (Details)
$ in Millions
Sep. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2020
claim
Oct. 31, 2020
claim
Loss Contingencies [Line Items]        
Self-insurance reserves $ 169 $ 169    
Excludes general and professional liability claims        
Loss Contingencies [Line Items]        
Litigation reserves 21 $ 4    
Secured Receivables Credit Facility        
Debt Instrument [Line Items]        
Letters of credit outstanding, amount $ 78      
401(k) Plan Lawsuit | Pending Litigation        
Loss Contingencies [Line Items]        
Class action lawsuits | claim     2 2
v3.25.3
BUSINESS SEGMENT INFORMATION (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Segment Reporting Information [Line Items]        
Percentage of net revenues 100.00% 100.00% 100.00% 100.00%
Total net revenues $ 2,816 $ 2,488 $ 8,229 $ 7,251
Segment operating income 386 330 1,170 985
Non-operating expense, net (58) (34) (182) (109)
Income before income taxes and equity in earnings of equity method investees 328 296 988 876
Income tax expense (77) (65) (233) (205)
Equity in earnings of equity method investees, net of taxes 8 6 35 14
Net income 259 237 790 685
Less: Net income attributable to noncontrolling interests 14 11 43 36
Net income attributable to Quest Diagnostics 245 226 747 649
Depreciation and amortization $ 142 $ 125 $ 425 $ 358
DIS business        
Segment Reporting Information [Line Items]        
Percentage of net revenues 98.00% 97.00% 98.00% 97.00%
Total net revenues $ 2,755 $ 2,427 $ 8,043 $ 7,058
Less: Other segment items 2,273 2,020 6,653 5,858
Segment operating income 482 407 1,390 1,200
Depreciation and amortization 99 90 296 258
All other operating segments        
Segment Reporting Information [Line Items]        
Total net revenues 61 61 186 193
Segment operating income 9 6 24 23
Depreciation and amortization 3 3 10 9
General corporate activities        
Segment Reporting Information [Line Items]        
Segment operating income (105) (83) (244) (238)
Depreciation and amortization $ 40 $ 32 $ 119 $ 91
Minimum | DIS business        
Segment Reporting Information [Line Items]        
Percentage of net revenues 97.00% 97.00% 97.00% 97.00%
v3.25.3
REVENUE RECOGNITION (Details)
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Segment Reporting Information [Line Items]          
Percentage of net revenues 100.00% 100.00% 100.00% 100.00%  
Net accounts receivable 100.00%   100.00%   100.00%
DIS business          
Segment Reporting Information [Line Items]          
Percentage of net revenues 98.00% 97.00% 98.00% 97.00%  
Net accounts receivable 98.00%   98.00%   98.00%
DIS business | Healthcare Insurers          
Segment Reporting Information [Line Items]          
Percentage of net revenues 39.00% 41.00% 39.00% 40.00%  
Net accounts receivable 29.00%   29.00%   26.00%
DIS business | Healthcare Insurers | Fee-for-service          
Segment Reporting Information [Line Items]          
Percentage of net revenues 37.00% 38.00% 36.00% 37.00%  
DIS business | Healthcare Insurers | Capitated          
Segment Reporting Information [Line Items]          
Percentage of net revenues 2.00% 3.00% 3.00% 3.00%  
DIS business | Government payers (principally fee-for-service)          
Segment Reporting Information [Line Items]          
Percentage of net revenues 16.00% 13.00% 16.00% 12.00%  
Net accounts receivable 9.00%   9.00%   7.00%
DIS business | Client Payers          
Segment Reporting Information [Line Items]          
Percentage of net revenues 31.00% 33.00% 31.00% 33.00%  
Net accounts receivable 41.00%   41.00%   45.00%
DIS business | Patients (including coinsurance and deductible responsibilities)          
Segment Reporting Information [Line Items]          
Percentage of net revenues 12.00% 10.00% 12.00% 12.00%  
Net accounts receivable 19.00%   19.00%   20.00%
DIS business | Minimum          
Segment Reporting Information [Line Items]          
Percentage of net revenues 97.00% 97.00% 97.00% 97.00%  
All other operating segments | DS Businesses          
Segment Reporting Information [Line Items]          
Percentage of net revenues 2.00% 3.00% 2.00% 3.00%  
Net accounts receivable 2.00%   2.00%   2.00%