Quest Diagnostics (DGX) 10-Q 22 Oct 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 15, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
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	2021
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		122,674,771

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net revenues	$ 2,774	$ 2,786	$ 8,044	$ 6,435
Operating costs and expenses and other operating income:
Cost of services	1,670	1,580	4,861	4,071
Selling, general and administrative	427	396	1,263	1,103
Amortization of intangible assets	25	27	77	77
Other operating expense (income), net	0	65	(2)	8
Total operating costs and expenses, net	2,122	2,068	6,199	5,259
Operating income	652	718	1,845	1,176
Other income (expense):
Interest expense, net	(38)	(42)	(114)	(124)
Other income, net	40	77	366	74
Total non-operating income (expense), net	2	35	252	(50)
Income before income taxes and equity in earnings of equity method investees	654	753	2,097	1,126
Income tax expense	(153)	(177)	(483)	(269)
Equity in earnings of equity method investees, net of taxes	26	15	53	33
Net income	527	591	1,667	890
Less: Net income attributable to noncontrolling interests	22	23	62	38
Net income attributable to Quest Diagnostics	$ 505	$ 568	$ 1,605	$ 852
Earnings per share attributable to Quest Diagnostics’ common stockholders:
Basic(in dollars per share)	$ 4.11	$ 4.20	$ 12.63	$ 6.33
Diluted (in dollars per share)	$ 4.02	$ 4.14	$ 12.41	$ 6.25
Weighted average common shares outstanding:
Basic (in Shares)	123	135	127	134
Diluted (in Shares)	125	137	129	136

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 527	$ 591	$ 1,667	$ 890
Other comprehensive income (loss):
Foreign currency translation adjustment	(4)	10	14	(6)
Net change in available-for-sale debt securities, net of taxes	0	0	(7)	0
Net deferred gain on cash flow hedges, net of taxes	1	3	1	3
Other comprehensive (loss) income	(3)	13	8	(3)
Comprehensive income	524	604	1,675	887
Less: Comprehensive income attributable to noncontrolling interests	22	23	62	38
Comprehensive income attributable to Quest Diagnostics	$ 502	$ 581	$ 1,613	$ 849

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) shares in Millions, $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Assets
Cash and cash equivalents	$ 987	$ 1,158
Accounts receivable, net of allowance for credit losses of $29 and $28 as of September 30, 2021 and December 31, 2020, respectively	1,473	1,520
Inventories	205	223
Prepaid expenses and other current assets	189	157
Total current assets	2,854	3,058
Property, plant and equipment, net	1,634	1,627
Operating lease right-of-use assets	596	604
Goodwill	7,057	6,873
Intangible assets, net	1,152	1,167
Investments in equity method investees	124	521
Other assets	155	176
Total assets	13,572	14,026
Liabilities and Stockholders' Equity
Accounts payable and accrued expenses	1,610	1,633
Current portion of long-term debt	1	2
Current portion of long-term operating lease liabilities	148	141
Total current liabilities	1,759	1,776
Long-term debt	4,006	4,013
Long-term operating lease liabilities	495	499
Other liabilities	801	847
Commitments and contingencies
Redeemable noncontrolling interest	79	82
Quest Diagnostics stockholders’ equity:
Common stock, par value $0.01 per share; 600 shares authorized as of both September 30, 2021 and December 31, 2020; 162 and 217 shares issued as of September 30, 2021 and December 31, 2020, respectively	2	2
Additional paid-in capital	1,936	2,841
Retained earnings	7,333	9,303
Accumulated other comprehensive loss	(13)	(21)
Treasury stock, at cost; 39 and 84 shares as of September 30, 2021 and December 31, 2020, respectively	(2,866)	(5,366)
Total Quest Diagnostics stockholders' equity	6,392	6,759
Noncontrolling interests	40	50
Total stockholders' equity	6,432	6,809
Total liabilities and stockholders' equity	$ 13,572	$ 14,026
Common stock, shares issued (in shares)	162	217

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 29	$ 28
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	217
Treasury stock (in shares)	39	84

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 1,667	$ 890
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	302	263
Provision for credit losses	3	18
Deferred income tax (benefit) provision	(87)	12
Stock-based compensation expense	60	63
Gain on disposition of joint venture	(314)	0
Other, net	(48)	(60)
Changes in operating assets and liabilities:
Accounts receivable	45	(355)
Accounts payable and accrued expenses	36	514
Income taxes payable	49	95
Termination of interest rate swap agreements	0	40
Other assets and liabilities, net	39	(16)
Net cash provided by operating activities	1,752	1,464
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(251)	(329)
Capital expenditures	(259)	(256)
Proceeds from disposition of joint venture	755	0
Decrease (increase) in investments and other assets	3	(19)
Net cash provided by (used in) investing activities	248	(604)
Cash flows from financing activities:
Proceeds from borrowings	0	749
Repayments of debt	(2)	(1,002)
Purchases of treasury stock	(1,910)	(75)
Exercise of stock options	108	144
Employee payroll tax withholdings on stock issued under stock-based compensation plans	(22)	(13)
Dividends paid	(232)	(222)
Distributions to noncontrolling interest partners	(75)	(34)
Other financing activities, net	(38)	6
Net cash used in financing activities	(2,171)	(447)
Net change in cash and cash equivalents and restricted cash	(171)	413
Cash and cash equivalents and restricted cash, beginning of period	1,158	1,192
Cash and cash equivalents and restricted cash, end of period	$ 987	$ 1,605

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock, at Cost	Non-controlling Interests
Balance, shares at Dec. 31, 2019		133
Balance, value at Dec. 31, 2019	$ 5,687	$ 2	$ 2,722	$ 8,174	$ (39)	$ (5,218)	$ 46
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	883			852			31
Other comprehensive income (loss), net of taxes	(3)				(3)
Dividends declared	(226)			(226)
Distributions to noncontrolling interest partners	(31)						(31)
Issuance of common stock under benefit plans, shares		1
Issuance of common stock under benefit plans	17		7			10
Stock-based compensation expense	63		63
Exercise of stock options, shares		2
Exercise of stock options	144		22			$ 122
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(13)		(13)
Purchases of treasury stock, shares		(1)				(0.7)
Purchases of treasury stock	(75)					$ (75)
Balance, shares at Sep. 30, 2020		135
Balance, value at Sep. 30, 2020	6,446	$ 2	2,801	8,800	(42)	(5,161)	46
Balance, Value at Dec. 31, 2019	76
Redeemable Non-controlling Interest [Abstract]
Net income	7
Distributions to noncontrolling interest partners	(3)
Balance, Value at Sep. 30, 2020	80
Balance, shares at Jun. 30, 2020		134
Balance, value at Jun. 30, 2020	5,881	$ 2	2,764	8,307	(55)	(5,187)	50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	586			568			18
Other comprehensive income (loss), net of taxes	13				13
Dividends declared	(75)			(75)
Distributions to noncontrolling interest partners	(22)						(22)
Issuance of common stock under benefit plans, shares		1
Issuance of common stock under benefit plans	4		1			3
Stock-based compensation expense	32		32
Exercise of stock options	27		4			23
Balance, shares at Sep. 30, 2020		135
Balance, value at Sep. 30, 2020	6,446	$ 2	2,801	8,800	(42)	(5,161)	46
Balance, Value at Jun. 30, 2020	77
Redeemable Non-controlling Interest [Abstract]
Net income	5
Distributions to noncontrolling interest partners	(2)
Balance, Value at Sep. 30, 2020	80
Balance, shares at Dec. 31, 2020		133
Balance, value at Dec. 31, 2020	6,809	$ 2	2,841	9,303	(21)	(5,366)	50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,658			1,605			53
Other comprehensive income (loss), net of taxes	8				8
Dividends declared	(233)			(233)
Distributions to noncontrolling interest partners	(63)						(63)
Issuance of common stock under benefit plans	17		(25)			42
Stock-based compensation expense	60		60
Exercise of stock options, shares		2
Exercise of stock options	108		19			89
Shares to cover employee payroll tax withholdings on stock issued under stock-based compensation plans	(22)		(10)			$ (12)
Purchases of treasury stock, shares		(12)				(12.5)
Purchases of treasury stock	(1,910)		(300)			$ (1,610)
Retirement of treasury stock	0		(649)	(3,342)		3,991
Balance, shares at Sep. 30, 2021		123
Balance, value at Sep. 30, 2021	6,432	$ 2	1,936	7,333	(13)	(2,866)	40
Balance, Value at Dec. 31, 2020	82
Redeemable Non-controlling Interest [Abstract]
Net income	9
Distributions to noncontrolling interest partners	(12)
Balance, Value at Sep. 30, 2021	79
Balance, shares at Jun. 30, 2021		122
Balance, value at Jun. 30, 2021	5,940	$ 2	2,555	10,246	(10)	(6,894)	41
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	524			505			19
Other comprehensive income (loss), net of taxes	(3)				(3)
Dividends declared	(76)			(76)
Distributions to noncontrolling interest partners	(20)						(20)
Issuance of common stock under benefit plans	6		2			4
Stock-based compensation expense	21		21
Exercise of stock options, shares		1
Exercise of stock options	40		7			33
Retirement of treasury stock	0		(649)	(3,342)		3,991
Balance, shares at Sep. 30, 2021		123
Balance, value at Sep. 30, 2021	6,432	$ 2	$ 1,936	$ 7,333	$ (13)	$ (2,866)	$ 40
Balance, Value at Jun. 30, 2021	78
Redeemable Non-controlling Interest [Abstract]
Net income	3
Distributions to noncontrolling interest partners	(2)
Balance, Value at Sep. 30, 2021	$ 79

DESCRIPTION OF BUSINESS

DESCRIPTION OF BUSINESS	9 Months Ended
	Sep. 30, 2021
Description of Business (Abstract)
DESCRIPTION OF BUSINESS	DESCRIPTION OF BUSINESS Background

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2021
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 2020 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2020 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 2020 Annual Report on Form 10-K. A novel strain of coronavirus (“COVID-19”) continues to impact the economy of the United States and other countries around the world. The Company's testing volume and revenues have been materially impacted by the COVID-19 pandemic, including periods of decline in testing volume in the Company's base business (which excludes COVID-19 testing) compared to historical 2019 levels and periods of significant demand for COVID-19 testing. As a result, operating results for the three and nine months ended September 30, 2021 may not be indicative of the results that may be expected for the full year. 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 and its Amended and Restated Non-Employee Director Long-Term Incentive Plan, as well as the dilutive effect of accelerated share repurchase agreements ("ASRs"). 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 March 2020, the Financial Accounting Standards Board issued a new accounting standard which provides temporary optional guidance to ease the potential burden in accounting for reference rate reform due to the risk of cessation of the London Interbank Offered Rate ("LIBOR"). The amendments apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The pronouncement is effective immediately and can be applied through December 31, 2022. The adoption of this standard is not expected to have a material impact on the Company’s consolidated results of operations, financial position or cash flows.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2021
Earnings Per Share, Basic and Diluted [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, 2021 2020 2021 2020 Amounts attributable to Quest Diagnostics’ common stockholders: Net income attributable to Quest Diagnostics $ 505 $ 568 $ 1,605 $ 852 Less: Earnings allocated to participating securities 2 2 6 3 Earnings available to Quest Diagnostics’ common stockholders – basic and diluted $ 503 $ 566 $ 1,599 $ 849 Weighted average common shares outstanding – basic 123 135 127 134 Effect of dilutive securities: Stock options and performance share units 2 2 2 2 Weighted average common shares outstanding – diluted 125 137 129 136 Earnings per share attributable to Quest Diagnostics’ common stockholders: Basic $ 4.11 $ 4.20 $ 12.63 $ 6.33 Diluted $ 4.02 $ 4.14 $ 12.41 $ 6.25 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, 2021 2020 2021 2020 Stock options and performance share units — 1 — 1 In April 2021, the Company entered into ASRs with several financial institutions to repurchase $1.5 billion of the Company's common stock as part of the Company's share repurchase program. See Note 9 for further details. The sum of basic and diluted earnings per share attributable to Quest Diagnostics' common stockholders for the first three quarters of 2021 did not equal the total for the nine months ended September 30, 2021 due to both quarterly fluctuations in the Company's earnings and in the weighted average common shares outstanding throughout the period as a result of the impact of the ASRs.

BUSINESS ACQUISITIONS

BUSINESS ACQUISITIONS	9 Months Ended
	Sep. 30, 2021
Business Combinations [Abstract]
BUSINESS ACQUISITIONS	BUSINESS ACQUISITIONS On June 1, 2021, the Company completed the acquisition of the outreach laboratory services business of Mercy Health, which serves providers and patients in Arkansas, Kansas, Missouri and Oklahoma, in an all-cash transaction for $225 million. Based on the preliminary purchase price allocation, which may be revised as additional information becomes available during the measurement period, the assets acquired primarily consist of $54 million of customer-related intangible assets and $171 million of tax-deductible goodwill. The intangible assets are being amortized over a useful life of 15 years. 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.

DISPOSITION

DISPOSITION	9 Months Ended
	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
DISPOSITION	DISPOSITION On April 1, 2021, the Company sold its 40% ownership interest in Q 2 Solutions ® ("Q 2 Solutions"), its clinical trials central laboratory services joint venture, to IQVIA Holdings, Inc. ("IQVIA"), its joint venture partner, for $760 million in an all-cash transaction. The sales price is subject to customary post-closing adjustments. Prior to the transaction, the Company accounted for its minority interest as an equity method investment. As a result of the transaction, during the nine months ended September 30, 2021, the Company recorded a $314 million pre-tax gain in other income, net in the consolidated statement of operations based on the difference between the net sales proceeds and the carrying value of the investment, including $20 million of cumulative translation losses which were previously recorded in accumulated other comprehensive loss. During the nine months ended September 30, 2021, the Company also recorded $55 million of income tax expense related to the gain, consisting of $127 million of current income tax expense, partially offset by $72 million of deferred income tax benefit. Under a multi-year agreement, the Company will remain the strategic preferred laboratory provider for Q 2 Solutions' clients, providing a range of lab testing capabilities to augment Q 2 Solutions' core offerings and extend its industry leading suite of services.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2021
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/Liabilities Significant Other Observable Inputs Significant Unobservable Inputs September 30, 2021 Total Level 1 Level 2 Level 3 Assets: Deferred compensation trading securities $ 75 $ 75 $ — $ — Cash surrender value of life insurance policies 54 — 54 — Equity investments 49 49 — — Available-for-sale debt securities 1 — — 1 Total $ 179 $ 124 $ 54 $ 1 Liabilities: Deferred compensation liabilities $ 139 $ — $ 139 $ — Redeemable noncontrolling interest $ 79 $ — $ — $ 79 Basis of Fair Value Measurements December 31, 2020 Total Level 1 Level 2 Level 3 Assets: Deferred compensation trading securities $ 67 $ 67 $ — $ — Cash surrender value of life insurance policies 50 — 50 — Available-for-sale debt securities 12 — — 12 Total $ 129 $ 67 $ 50 $ 12 Liabilities: Deferred compensation liabilities $ 126 $ — $ 126 $ — Redeemable noncontrolling interest $ 82 $ — $ — $ 82 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 2020 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 investment options that are classified as trading securities. These 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. Equity investments that do not have readily determinable fair values (which consist of investments in preferred and common shares of private companies) are measured at cost minus impairment, if any, plus or minus changes resulting from observable price changes. During the three months ended September 30, 2021, certain of the Company's equity investments became publicly-traded and, based on the readily determinable fair values, the Company recognized gains of $42 million in other income, net in the Company's consolidated statement of operations. Such equity investments are now 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 Company's available-for-sale debt securities are measured at fair value based on estimated future cash flows. These fair value measurements are classified within Level 3 of the fair value hierarchy as the fair value is based on significant inputs that are not observable, including cash flow projections. 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, 2021, 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. During the nine months ended September 30, 2021, the Company recorded an $8 million impairment charge, which is included in equity in earnings of equity method investees, net of taxes, in order to adjust to fair value an investment that is accounted for under the equity method of accounting. Following the impairment charge, the carrying value of the investment is not material. 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, including cash flow projections. 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, 2021 and December 31, 2020, the fair value of the Company’s debt was estimated at $4.5 billion and $4.6 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.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	GOODWILL AND INTANGIBLE ASSETS The changes in goodwill for the nine months ended September 30, 2021 and for the year ended December 31, 2020 were as follows: September 30, 2021 December 31, 2020 Balance, beginning of period $ 6,873 $ 6,619 Goodwill acquired during the period 188 247 Adjustments to goodwill (4) 7 Balance, end of period $ 7,057 $ 6,873 Principally all of the Company’s goodwill as of September 30, 2021 and December 31, 2020 was associated with its DIS business. For the nine months ended September 30, 2021, goodwill acquired was principally associated with the acquisition of the outreach laboratory services businesses of Mercy Health and adjustments to goodwill primarily related to foreign currency translation. For the year ended December 31, 2020, goodwill acquired was principally associated with the acquisitions of Blueprint Genetics Oy; Memorial Hermann Diagnostic Laboratories, the outreach laboratory division of Memorial Hermann Health System; and the remaining 56% interest in Mid America Clinical Laboratories, LLC (see Note 6 to the audited consolidated financial statements in the Company's 2020 Annual Report on Form 10-K). For the year ended December 31, 2020, adjustments to goodwill primarily related to foreign currency translation. Intangible assets as of September 30, 2021 and December 31, 2020 consisted of the following: Weighted September 30, 2021 December 31, 2020 Cost Accumulated Net Cost Accumulated Net Amortizing intangible assets: Customer-related 17 $ 1,541 $ (704) $ 837 $ 1,479 $ (638) $ 841 Non-compete agreements 9 3 (2) 1 3 (2) 1 Technology 14 142 (72) 70 141 (65) 76 Other 5 108 (100) 8 108 (95) 13 Total 17 1,794 (878) 916 1,731 (800) 931 Intangible assets not subject to amortization: Trade names 235 — 235 235 — 235 Other 1 — 1 1 — 1 Total intangible assets $ 2,030 $ (878) $ 1,152 $ 1,967 $ (800) $ 1,167 The estimated amortization expense related to amortizable intangible assets for each of the five succeeding fiscal years and thereafter as of September 30, 2021 is as follows: Year Ending December 31, Remainder of 2021 $ 26 2022 102 2023 100 2024 97 2025 96 2026 90 Thereafter 405 Total $ 916

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
FINANCIAL INSTRUMENTS	FINANCIAL INSTRUMENTS The Company uses derivative financial instruments to manage its exposure to market risks for changes in interest rates and, from time to time, 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 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 Historically, the Company has entered into various fixed-to-variable interest rate swap agreements in order to convert a portion of the Company's long-term debt into variable interest rate debt. All such fixed-to-variable interest rate swap agreements have been terminated and proceeds from the terminations have been reflected as basis adjustments to the hedged debt instruments and are being amortized as a reduction of interest expense, net over the remaining terms of such debt instruments. As of September 30, 2021 and December 31, 2020, 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: Hedge Accounting Basis Adjustment (a) Balance Sheet Classification September 30, 2021 December 31, 2020 Long-term debt $ 41 $ 51 (a) As of both September 30, 2021 and December 31, 2020, the entire balance is associated with remaining unamortized hedging adjustments on discontinued relationships. The following table presents the effect of fair value hedge accounting on the consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Other income, net Other income, net Other income, net Other income, net Total for line item in which the effects of fair value hedges are recorded $ 40 $ 77 $ 366 $ 74 Gain (loss) on fair value hedging relationships: Hedged items (Long-term debt) $ — $ — $ — $ (68) Derivatives designated as hedging instruments $ — $ — $ — $ 68

STOCKHOLDERS_ EQUITY AND REDEEM

STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Attributable to Parent [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, 2021 and 2020, 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. On April 1, 2021, the Company sold its 40% ownership interest in Q 2 Solutions, its clinical trials central laboratory services joint venture, to IQVIA, its joint venture partner. As a result of the transaction, during the nine months ended September 30, 2021, $20 million of cumulative translation losses were reclassified from accumulated other comprehensive loss to other income, net. See Note 5 for further details. Dividend Program During each of the first three quarters of 2021, the Company's Board of Directors declared a quarterly cash dividend of $0.62 per common share. During each of the four quarters of 2020, the Company's Board of Directors declared a quarterly cash dividend of $0.56 per common share. Share Repurchase Program In each of February 2021 and March 2021, the Company's Board of Directors increased the size of its share repurchase program by $1 billion. As of September 30, 2021, $1.3 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, 2021, the Company repurchased 12.5 million shares of its common stock for a value of $1.6 billion, including 9.1 million shares repurchased under ASRs. The repurchases under the ASRs were initiated in April 2021 with the Company's entry into ASRs with several financial institutions to repurchase $1.5 billion of the Company's common stock as part of the Company's share repurchase program. Each of the ASRs was structured to permit the Company to purchase shares immediately with the final purchase price of those shares determined by the volume-weighted average price of the Company's common stock during the repurchase period, less a fixed discount and was accounted for as two transactions: (1) a treasury stock repurchase and (2) a forward contract. For the nine months ended September 30, 2021, the Company paid $1.5 billion to the financial institutions and received 9.1 million shares of its common stock, at an initial price of $132.27 per share for a value of $1.2 billion, which represents 80% of the total value of shares to be repurchased under the ASRs. The ASR contracts will settle the remaining shares, based on the volume-weighted average price of the Company's common stock during the repurchase period, less a fixed discount, upon the completion of the ASRs during the fourth quarter of 2021. The Company recorded the transactions as an increase to treasury stock of $1.2 billion and it recorded the remaining $300 million as a decrease to additional paid-in capital in the Company’s consolidated balance sheet. The $300 million recorded in additional paid-in capital will be included in treasury stock upon completion of the ASRs. For the nine months ended September 30, 2020, the Company repurchased 0.7 million shares of its common stock for $75 million. Shares Reissued from Treasury Stock The Company's practice has been to issue shares related to its Employee Stock Purchase Plan ("ESPP") and its stock-based compensation program from shares of its common stock held in treasury or by issuing new shares of its common stock. In January 2021, the Company began to issue shares related to its ESPP and stock-based compensation program solely from common stock held in treasury. For the nine months ended September 30, 2021 and 2020, the Company reissued 1.7 million shares and 2.1 million shares, respectively from treasury stock. For details regarding the Company's stock ownership and compensation plans, see Note 17 to the audited consolidated financial statements in the Company's 2020 Annual Report on Form 10-K. Treasury Stock Retirement During the three months ended September 30, 2021, the Company retired 55 million shares of treasury stock. In accordance with the Company's policy, the amount paid to repurchase the shares in excess of par value was allocated between retained earnings and additional paid-in capital based on a pro-rata allocation of additional paid-in capital at the time of the share retirement. 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, 2021 and December 31, 2020, the redeemable noncontrolling interest was presented at its fair value. For further information regarding the fair value of the redeemable noncontrolling interest, see Note 6.

SUPPLEMENTAL CASH FLOW & OTHER

SUPPLEMENTAL CASH FLOW & OTHER DATA	9 Months Ended
	Sep. 30, 2021
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, 2021 and 2020 was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Depreciation expense $ 76 $ 62 $ 225 $ 186 Amortization expense 25 27 77 77 Depreciation and amortization expense $ 101 $ 89 $ 302 $ 263 Interest expense $ (38) $ (42) $ (114) $ (126) Interest income — — — 2 Interest expense, net $ (38) $ (42) $ (114) $ (124) Interest paid $ 33 $ 33 $ 111 $ 136 Income taxes paid $ 187 $ 148 $ 522 $ 168 Accounts payable associated with capital expenditures $ 24 $ 55 $ 24 $ 55 Dividends payable $ 77 $ 76 $ 77 $ 76 Businesses acquired: Fair value of assets acquired $ 20 $ 126 $ 254 $ 377 Fair value of liabilities assumed — (9) (3) (29) Fair value of net assets acquired 20 117 251 348 Merger consideration receivable/payable — 2 — 2 Cash paid for business acquisitions 20 119 251 350 Less: Cash acquired — 18 — 21 Business acquisitions, net of cash acquired $ 20 $ 101 $ 251 $ 329 Leases: Leased assets obtained in exchange for new operating lease liabilities $ 46 $ 40 $ 115 $ 119 In March 2020, in response to the COVID-19 pandemic, the Coronavirus Aid, Relief, and Economic Security Act ("CARES Act") was signed into law. In April 2020 and August 2020, the Company received approximately $65 million and $73 million, respectively, of funds that were distributed to healthcare providers for related expenses or lost revenues that are attributable to the COVID-19 pandemic under the CARES Act. The Company accounted for the receipt of the funds under a gain contingency model. Accordingly, the amounts were recognized when the funds were received and the Company determined that it satisfied the associated terms and conditions. During the three months ended June 30, 2020, based on the terms and conditions that were in effect at such time, the Company concluded that it had satisfied such terms and conditions for the $65 million of funds that were received in April 2020 and, therefore, the Company recognized such amount in other operating expense (income), net during the second quarter of 2020. During the three months ended September 30, 2020, the Company reversed the $65 million of funds that had previously been recognized and, during the three months ended December 31, 2020, the Company returned the entire $138 million of funds.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Letters of Credit The Company can issue letters of credit totaling $100 million under its $600 million secured receivables credit facility and $150 million under its $750 million senior unsecured revolving credit facility. See Note 13 to the audited consolidated financial statements in the Company's 2020 Annual Report on Form 10-K. In support of its risk management program, $70 million in letters of credit under the secured receivables credit facility were outstanding as of September 30, 2021, 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 2020 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. 401(k) Plan Lawsuit 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. AMCA Data Security Incident 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 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 is pending. In addition, certain federal and state governmental authorities are investigating, or otherwise seeking information and/or documents from the Company related to the AMCA Data Security Incident and related matters, including the Office for Civil Rights of the U.S. Department of Health and Human Services, Attorneys General offices from numerous states and the District of Columbia, and certain U.S. senators. 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 "whistle blowers" 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, 2021, the Company does not believe that material losses related to legal matters are probable. Reserves for legal matters totaled $6 million and $1 million as of September 30, 2021 and December 31, 2020, respectively. Reserves for General and Professional Liability Claims

BUSINESS SEGMENT INFORMATION

BUSINESS SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2021
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 DIS business provides diagnostic information services to a broad range of customers, including patients, clinicians, hospitals, IDNs, health plans, employers, ACOs and DCEs. The Company is the world's leading provider of diagnostic information services, which includes providing information and insights based on an industry-leading menu of routine, non-routine and advanced clinical testing and anatomic pathology testing, and other diagnostic information services. The DIS business accounted for greater than 95% of net revenues in 2021 and 2020. 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 are the leading provider of risk assessment services for the life insurance industry and offer healthcare organizations and clinicians robust information technology solutions. As of September 30, 2021, 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. The following table is a summary of segment information for the three and nine months ended September 30, 2021 and 2020. Segment asset information is not presented since it is not used by the CODM at the operating segment level. Operating earnings (loss) of each segment represents net revenues less directly identifiable expenses to arrive at operating income (loss) for the segment. General corporate activities included in the table below are comprised of general management and administrative corporate expenses, amortization and impairment of intangible 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 2020 Annual Report on Form 10-K and Note 2 to the interim unaudited consolidated financial statements. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net revenues: DIS business $ 2,703 $ 2,709 $ 7,820 $ 6,217 All other operating segments 71 77 224 218 Total net revenues $ 2,774 $ 2,786 $ 8,044 $ 6,435 Operating earnings (loss): DIS business $ 713 $ 840 $ 2,026 $ 1,325 All other operating segments 8 16 26 29 General corporate activities (69) (138) (207) (178) Total operating income 652 718 1,845 1,176 Non-operating income (expense), net 2 35 252 (50) Income before income taxes and equity in earnings of equity method investees 654 753 2,097 1,126 Income tax expense (153) (177) (483) (269) Equity in earnings of equity method investees, net of taxes 26 15 53 33 Net income 527 591 1,667 890 Less: Net income attributable to noncontrolling interests 22 23 62 38 Net income attributable to Quest Diagnostics $ 505 $ 568 $ 1,605 $ 852 Net revenues by major service were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Routine clinical testing services $ 1,210 $ 1,055 $ 3,392 $ 2,812 COVID-19 testing services 709 965 2,048 1,571 Gene-based and esoteric (including advanced diagnostics) testing services 646 556 1,972 1,491 Anatomic pathology testing services 138 133 408 343 All other 71 77 224 218 Total net revenues $ 2,774 $ 2,786 $ 8,044 $ 6,435

REVENUE RECOGNITION

REVENUE RECOGNITION	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
REVENUE RECOGITION	REVENUE RECOGNITION DIS Net revenues in the Company’s DIS business accounted for over 95% of the Company’s total net revenues for the three and nine months ended September 30, 2021 and 2020 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 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 customers: healthcare insurers, government payers (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 2020 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. The approximate percentage of net revenue by type of customer was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Healthcare insurers: Fee-for-service 41 % 33 % 39 % 33 % Capitated 2 2 3 3 Total healthcare insurers 43 35 42 36 Government payers 10 10 10 12 Client payers 31 40 33 37 Patients 13 12 12 12 Total DIS 97 97 97 97 DS 3 3 3 3 Net revenues 100 % 100 % 100 % 100 % The approximate percentage of net accounts receivable by type of customer was as follows: September 30, 2021 December 31, 2020 Healthcare Insurers 35 % 34 % Government Payers 6 6 Client Payers 36 46 Patients (including coinsurance and deductible responsibilities) 20 11 Total DIS 97 97 DS 3 3 Net accounts receivable 100 % 100 %

TAXES ON INCOME

TAXES ON INCOME	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
TAXES ON INCOME	TAXES ON INCOME For the three months ended September 30, 2021 and 2020, the effective income tax rate was 23.4% and 23.7%, respectively. The effective income tax rate for the three months ended September 30, 2021, benefited from a $6 million income tax benefit associated with changes in reserves for uncertain tax positions, and $6 million of excess tax benefits associated with stock-based compensation. The effective income tax rate for the three months ended September 30, 2020, benefited from a lower effective income tax rate, 11.8%, associated with a $70 million gain recognized as a result of the remeasurement of the Company's previously held equity interest in Mid America Clinical Laboratories, LLC ("MACL") to fair value, and $3 million of excess tax benefits associated with stock-based compensation. For the nine months ended September 30, 2021 and 2020, the effective income tax rate was 23.1% and 23.9%, respectively. For the nine months ended September 30, 2021, the effective income tax rate benefited from a lower effective income tax rate, 17.6%, on the gain on the sale of the Company's 40% ownership interest in Q 2 Solutions (see Note 5). For the nine months ended September 30, 2020, the effective income tax rate benefited from a lower effective income tax rate, 11.8%, associated with a $70 million gain recognized as a result of the remeasurement of the Company's previously held equity interest in MACL to fair value. In addition, the effective income tax rate benefited from $15 million of excess tax benefits associated with stock-based compensation arrangements for both the nine months ended September 30, 2021 and 2020.

SUBSEQUENT EVENT

SUBSEQUENT EVENT	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENT    During October 2021, the Company amended its $600 million secured receivables credit facility in order to extend the maturity dates for each underlying commitment by one year while maintaining the aggregate borrowing capacity under the secured receivables credit facility at $600 million. Under the secured receivables credit facility, the Company can borrow against a $250 million loan commitment maturing October 2022 and a $250 million loan commitment maturing October 2023. Additionally, the Company can issue up to $100 million of letters of credit through October 2023. Borrowings under the secured receivables credit facility are collateralized by certain domestic receivables. Interest on borrowings under the secured receivables credit facility are based on either commercial paper rates for highly-rated issuers or LIBOR, plus a spread of 0.725% to 0.80%.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2021
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 2020 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2020 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 and its Amended and Restated Non-Employee Director Long-Term Incentive Plan, as well as the dilutive effect of accelerated share repurchase agreements ("ASRs"). 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 March 2020, the Financial Accounting Standards Board issued a new accounting standard which provides temporary optional guidance to ease the potential burden in accounting for reference rate reform due to the risk of cessation of the London Interbank Offered Rate ("LIBOR"). The amendments apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The pronouncement is effective immediately and can be applied through December 31, 2022. The adoption of this standard is not expected to have a material impact on the Company’s consolidated results of operations, financial position or cash flows.
Derivative Financial Instruments	The Company uses derivative financial instruments to manage its exposure to market risks for changes in interest rates and, from time to time, 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 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.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share, Basic and Diluted [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, 2021 2020 2021 2020 Amounts attributable to Quest Diagnostics’ common stockholders: Net income attributable to Quest Diagnostics $ 505 $ 568 $ 1,605 $ 852 Less: Earnings allocated to participating securities 2 2 6 3 Earnings available to Quest Diagnostics’ common stockholders – basic and diluted $ 503 $ 566 $ 1,599 $ 849 Weighted average common shares outstanding – basic 123 135 127 134 Effect of dilutive securities: Stock options and performance share units 2 2 2 2 Weighted average common shares outstanding – diluted 125 137 129 136 Earnings per share attributable to Quest Diagnostics’ common stockholders: Basic $ 4.11 $ 4.20 $ 12.63 $ 6.33 Diluted $ 4.02 $ 4.14 $ 12.41 $ 6.25
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, 2021 2020 2021 2020 Stock options and performance share units — 1 — 1

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2021
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/Liabilities Significant Other Observable Inputs Significant Unobservable Inputs September 30, 2021 Total Level 1 Level 2 Level 3 Assets: Deferred compensation trading securities $ 75 $ 75 $ — $ — Cash surrender value of life insurance policies 54 — 54 — Equity investments 49 49 — — Available-for-sale debt securities 1 — — 1 Total $ 179 $ 124 $ 54 $ 1 Liabilities: Deferred compensation liabilities $ 139 $ — $ 139 $ — Redeemable noncontrolling interest $ 79 $ — $ — $ 79 Basis of Fair Value Measurements December 31, 2020 Total Level 1 Level 2 Level 3 Assets: Deferred compensation trading securities $ 67 $ 67 $ — $ — Cash surrender value of life insurance policies 50 — 50 — Available-for-sale debt securities 12 — — 12 Total $ 129 $ 67 $ 50 $ 12 Liabilities: Deferred compensation liabilities $ 126 $ — $ 126 $ — Redeemable noncontrolling interest $ 82 $ — $ — $ 82

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Goodwill, Net	The changes in goodwill for the nine months ended September 30, 2021 and for the year ended December 31, 2020 were as follows: September 30, 2021 December 31, 2020 Balance, beginning of period $ 6,873 $ 6,619 Goodwill acquired during the period 188 247 Adjustments to goodwill (4) 7 Balance, end of period $ 7,057 $ 6,873
Intangible Assets Excluding Goodwill	Intangible assets as of September 30, 2021 and December 31, 2020 consisted of the following: Weighted September 30, 2021 December 31, 2020 Cost Accumulated Net Cost Accumulated Net Amortizing intangible assets: Customer-related 17 $ 1,541 $ (704) $ 837 $ 1,479 $ (638) $ 841 Non-compete agreements 9 3 (2) 1 3 (2) 1 Technology 14 142 (72) 70 141 (65) 76 Other 5 108 (100) 8 108 (95) 13 Total 17 1,794 (878) 916 1,731 (800) 931 Intangible assets not subject to amortization: Trade names 235 — 235 235 — 235 Other 1 — 1 1 — 1 Total intangible assets $ 2,030 $ (878) $ 1,152 $ 1,967 $ (800) $ 1,167
Future Amortization Expense Intangible Assets	The estimated amortization expense related to amortizable intangible assets for each of the five succeeding fiscal years and thereafter as of September 30, 2021 is as follows: Year Ending December 31, Remainder of 2021 $ 26 2022 102 2023 100 2024 97 2025 96 2026 90 Thereafter 405 Total $ 916

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Debt Instrument Fair Value Basis Adjustment Attributable to Hedged Debt	As of September 30, 2021 and December 31, 2020, 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: Hedge Accounting Basis Adjustment (a) Balance Sheet Classification September 30, 2021 December 31, 2020 Long-term debt $ 41 $ 51 (a) As of both September 30, 2021 and December 31, 2020, the entire balance is associated with remaining unamortized hedging adjustments on discontinued relationships.
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 statements of operations for the three and nine months ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Other income, net Other income, net Other income, net Other income, net Total for line item in which the effects of fair value hedges are recorded $ 40 $ 77 $ 366 $ 74 Gain (loss) on fair value hedging relationships: Hedged items (Long-term debt) $ — $ — $ — $ (68) Derivatives designated as hedging instruments $ — $ — $ — $ 68

SUPPLEMENTAL CASH FLOW & OTHE_2

SUPPLEMENTAL CASH FLOW & OTHER DATA (Tables)	9 Months Ended
	Sep. 30, 2021
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, 2021 and 2020 was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Depreciation expense $ 76 $ 62 $ 225 $ 186 Amortization expense 25 27 77 77 Depreciation and amortization expense $ 101 $ 89 $ 302 $ 263 Interest expense $ (38) $ (42) $ (114) $ (126) Interest income — — — 2 Interest expense, net $ (38) $ (42) $ (114) $ (124) Interest paid $ 33 $ 33 $ 111 $ 136 Income taxes paid $ 187 $ 148 $ 522 $ 168 Accounts payable associated with capital expenditures $ 24 $ 55 $ 24 $ 55 Dividends payable $ 77 $ 76 $ 77 $ 76 Businesses acquired: Fair value of assets acquired $ 20 $ 126 $ 254 $ 377 Fair value of liabilities assumed — (9) (3) (29) Fair value of net assets acquired 20 117 251 348 Merger consideration receivable/payable — 2 — 2 Cash paid for business acquisitions 20 119 251 350 Less: Cash acquired — 18 — 21 Business acquisitions, net of cash acquired $ 20 $ 101 $ 251 $ 329 Leases: Leased assets obtained in exchange for new operating lease liabilities $ 46 $ 40 $ 115 $ 119

BUSINESS SEGMENT INFORMATION (T

BUSINESS SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2021
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, 2021 and 2020. Segment asset information is not presented since it is not used by the CODM at the operating segment level. Operating earnings (loss) of each segment represents net revenues less directly identifiable expenses to arrive at operating income (loss) for the segment. General corporate activities included in the table below are comprised of general management and administrative corporate expenses, amortization and impairment of intangible 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 2020 Annual Report on Form 10-K and Note 2 to the interim unaudited consolidated financial statements. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net revenues: DIS business $ 2,703 $ 2,709 $ 7,820 $ 6,217 All other operating segments 71 77 224 218 Total net revenues $ 2,774 $ 2,786 $ 8,044 $ 6,435 Operating earnings (loss): DIS business $ 713 $ 840 $ 2,026 $ 1,325 All other operating segments 8 16 26 29 General corporate activities (69) (138) (207) (178) Total operating income 652 718 1,845 1,176 Non-operating income (expense), net 2 35 252 (50) Income before income taxes and equity in earnings of equity method investees 654 753 2,097 1,126 Income tax expense (153) (177) (483) (269) Equity in earnings of equity method investees, net of taxes 26 15 53 33 Net income 527 591 1,667 890 Less: Net income attributable to noncontrolling interests 22 23 62 38 Net income attributable to Quest Diagnostics $ 505 $ 568 $ 1,605 $ 852
Schedule of Revenues by Major Service	Net revenues by major service were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Routine clinical testing services $ 1,210 $ 1,055 $ 3,392 $ 2,812 COVID-19 testing services 709 965 2,048 1,571 Gene-based and esoteric (including advanced diagnostics) testing services 646 556 1,972 1,491 Anatomic pathology testing services 138 133 408 343 All other 71 77 224 218 Total net revenues $ 2,774 $ 2,786 $ 8,044 $ 6,435

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The approximate percentage of net revenue by type of customer was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Healthcare insurers: Fee-for-service 41 % 33 % 39 % 33 % Capitated 2 2 3 3 Total healthcare insurers 43 35 42 36 Government payers 10 10 10 12 Client payers 31 40 33 37 Patients 13 12 12 12 Total DIS 97 97 97 97 DS 3 3 3 3 Net revenues 100 % 100 % 100 % 100 %
Accounts Receivable Disaggregation	The approximate percentage of net accounts receivable by type of customer was as follows: September 30, 2021 December 31, 2020 Healthcare Insurers 35 % 34 % Government Payers 6 6 Client Payers 36 46 Patients (including coinsurance and deductible responsibilities) 20 11 Total DIS 97 97 DS 3 3 Net accounts receivable 100 % 100 %

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Amounts attributable to Quest Diagnostics’ common stockholders:
Net income attributable to Quest Diagnostics		$ 505	$ 568	$ 1,605	$ 852
Less: Earnings allocated to participating securities		2	2	6	3
Earnings available to Quest Diagnostics’ common stockholders – basic and diluted		$ 503	$ 566	$ 1,599	$ 849
Weighted average common shares outstanding - basic		123	135	127	134
Stock options and performance share units		2	2	2	2
Weighted average common shares outstanding - diluted		125	137	129	136
Basic(in dollars per share)		$ 4.11	$ 4.20	$ 12.63	$ 6.33
Diluted (in dollars per share)		$ 4.02	$ 4.14	$ 12.41	$ 6.25
Stock options and performance share units		0	1	0	1
ASRs
Accelerated Share Repurchases [Line Items]
Accelerated share repurchases price paid	$ 1,500

BUSINESS ACQUISITIONS (Details)

BUSINESS ACQUISITIONS (Details) - USD ($) $ in Millions	Jun. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Cash paid for business acquisitions		$ 20	$ 119	$ 251	$ 350
Goodwill		$ 7,057		$ 7,057		$ 6,873	$ 6,619
Customer Relationships
Business Acquisition [Line Items]
Intangible assets, useful life				17 years
Mercy Health
Business Acquisition [Line Items]
Cash paid for business acquisitions	$ 225
Goodwill	171
Goodwill, expected tax deductible amount	171
Mercy Health | Customer Relationships
Business Acquisition [Line Items]
Intangible assets	$ 54
Intangible assets, useful life	15 years

DISPOSITION (Details)

DISPOSITION (Details) - USD ($) $ in Millions	Apr. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense		$ 153	$ 177	$ 483	$ 269
Deferred income tax (benefit) provision				(87)	$ 12
Q2 Solutions | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent of ownership interest sold	40.00%
Gross proceeds from disposition of joint venture	$ 760
Income tax expense				55
Current income tax expense (benefit)				127
Deferred income tax (benefit) provision				72
Q2 Solutions | Disposed of by Sale | Foreign Currency Translation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amounts reclassified from accumulated other comprehensive (loss) income				20
Q2 Solutions | Disposed of by Sale | Other Income
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of investment, before tax				$ (314)

FAIR VALUE MEASUREMENTS (Recogn

FAIR VALUE MEASUREMENTS (Recognized Assets and Liabilities at Fair Value) (Details) - Recurring Basis - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 75	$ 67
Cash surrender value of life insurance policies	54	50
Equity investments	49
Available-for-sale debt securities	1	12
Total	179	129
Deferred compensation liabilities	139	126
Redeemable noncontrolling interest	79	82
Quoted Prices in Active Markets for Identical Assets / Liabilities, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	75	67
Cash surrender value of life insurance policies	0	0
Equity investments	49
Available-for-sale debt securities	0	0
Total	124	67
Deferred compensation liabilities	0	0
Redeemable noncontrolling interest	0	0
Significant Other Observable Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Cash surrender value of life insurance policies	54	50
Equity investments	0
Available-for-sale debt securities	0	0
Total	54	50
Deferred compensation liabilities	139	126
Significant Unobservable Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Cash surrender value of life insurance policies	0	0
Equity investments	0
Available-for-sale debt securities	1	12
Total	1	12
Deferred compensation liabilities	0	0
Redeemable noncontrolling interest	$ 79	$ 82

FAIR VALUE MEASUREMENTS (Narrat

FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020	Jul. 01, 2015
Fair Value Disclosures [Abstract]
Equity securities, gains	$ 42
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	$ 4,500	$ 4,500	$ 4,600
Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Impairment of equity method investment		$ 8
UMass Joint Venture
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Ownership percentage by noncontrolling owners				18.90%

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS (Goodwill) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Goodwill, Balance at beginning of period	$ 6,873	$ 6,619
Goodwill acquired during the period	188	247
Adjustments to goodwill	(4)	7
Goodwill, Balance at end of period	$ 7,057	$ 6,873
MACL
Business Acquisition [Line Items]
Percentage of interests acquired		56.00%

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS (Schedules) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, Cost	$ 2,030		$ 2,030		$ 1,967
Intangible assets, Accumulated Amortization	(878)		(878)		(800)
Total intangible assets, Net	1,152		1,152		1,167
Amortization expense	25	$ 27	77	$ 77
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2021	26		26
2022	102		102
2023	100		100
2024	97		97
2025	96		96
2026	90		90
Thereafter	405		405
Total	916		916
Intangible Assets Not Subject to Amortization - Tradenames
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, Cost	235		235		235
Total intangible assets, Net	235		235		235
Intangible Assets Not Subject to Amortization - Other
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, Cost	1		1		1
Total intangible assets, Net	1		$ 1		1
Customer-related intangibles
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			17 years
Intangible assets, Cost	1,541		$ 1,541		1,479
Intangible assets, Accumulated Amortization	(704)		(704)		(638)
Total intangible assets, Net	837		$ 837		841
Non-compete agreements
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			9 years
Intangible assets, Cost	3		$ 3		3
Intangible assets, Accumulated Amortization	(2)		(2)		(2)
Total intangible assets, Net	1		$ 1		1
Technology
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			14 years
Intangible assets, Cost	142		$ 142		141
Intangible assets, Accumulated Amortization	(72)		(72)		(65)
Total intangible assets, Net	70		$ 70		76
Other
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			5 years
Intangible assets, Cost	108		$ 108		108
Intangible assets, Accumulated Amortization	(100)		(100)		(95)
Total intangible assets, Net	8		$ 8		13
Total Amortizing Intangible Assets
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			17 years
Intangible assets, Cost	1,794		$ 1,794		1,731
Intangible assets, Accumulated Amortization	(878)		(878)		(800)
Total intangible assets, Net	$ 916		$ 916		$ 931

FINANCIAL INSTRUMENTS (Balance

FINANCIAL INSTRUMENTS (Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Long-term Debt | Fair Value Hedging
Derivative [Line Items]
Hedge Accounting Basis Adjustment	$ 41	$ 51

FINANCIAL INSTRUMENTS (Income S

FINANCIAL INSTRUMENTS (Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative [Line Items]
Other income, net	$ 40	$ 77	$ 366	$ 74
Other Nonoperating Income (Expense)
Derivative [Line Items]
Hedged items (Long-term debt)	0	0	0	(68)
Other Nonoperating Income (Expense) | Fair Value Hedging
Derivative [Line Items]
Derivatives designated as hedging instruments	$ 0	$ 0	$ 0	$ 68

STOCKHOLDERS_ EQUITY AND REDE_2

STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST (Details) - USD ($) $ / shares in Units, shares in Millions

1 Months Ended

3 Months Ended

9 Months Ended

Mar. 31, 2021

Feb. 28, 2021

Sep. 30, 2021

Jun. 30, 2021

Mar. 31, 2021

Dec. 31, 2020

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Sep. 30, 2021

Sep. 30, 2020

Apr. 30, 2021

Apr. 01, 2021

Jul. 01, 2015

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Dividends per common share

$ 0.62

$ 0.62

$ 0.62

$ 0.56

$ 0.56

$ 0.56

$ 0.56

Additional amount authorized

$ 1,000,000,000

$ 1,000,000,000

Share repurchase authorization remaining available

$ 1,300,000,000

$ 1,300,000,000

Purchases of treasury stock, value

$ 1,910,000,000

$ 75,000,000

Accelerated share repurchase, initial purchase price, per share

$ 132.27

Reissuance of shares for employee benefit plan

1.7

2.1

Treasury stock retired (in shares)

55

UMass Joint Venture

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Ownership percentage by noncontrolling owners

18.90%

ASRs

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Accelerated share repurchases

$ 1,500,000,000

Value of shares to be received under accelerated share repurchase agreements at execution

$ 1,200,000,000

Accelerated share repurchase, percent of total value to be repurchased

80.00%

Treasury Stock, at Cost

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Purchases of treasury stock- shares

12.5

0.7

Purchases of treasury stock, value

$ 1,610,000,000

$ 75,000,000

Treasury Stock, at Cost | ASRs

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Purchases of treasury stock- shares

9.1

Stockholders' equity, period Increase (decrease)

$ 1,200,000,000

Additional Paid-In Capital

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Purchases of treasury stock, value

300,000,000

Additional Paid-In Capital | ASRs

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Stockholders' equity, period Increase (decrease)

(300,000,000)

Amount recorded in additional paid-in capital that will be included in treasury stock upon completion of the accelerated share repurchase agreements

300,000,000

Q2 Solutions | Disposed of by Sale

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Percent of ownership interest sold

40.00%

Q2 Solutions | Disposed of by Sale | Foreign Currency Translation

Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]

Amounts reclassified from accumulated other comprehensive (loss) income

$ 20,000,000

SUPPLEMENTAL CASH FLOW & OTHE_3

SUPPLEMENTAL CASH FLOW & OTHER DATA (Schedule) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Depreciation expense	$ 76	$ 62	$ 225	$ 186
Amortization expense	25	27	77	77
Depreciation and amortization expense	101	89	302	263
Interest expense	(38)	(42)	(114)	(126)
Interest income	0	0	0	2
Interest expense, net	(38)	(42)	(114)	(124)
Interest paid	33	33	111	136
Income taxes paid	187	148	522	168
Accounts payable associated with capital expenditures	24	55	24	55
Dividends payable	77	76	77	76
Fair value of assets acquired	20	126	254	377
Fair value of liabilities assumed	0	(9)	(3)	(29)
Fair value of net assets acquired	20	117	251	348
Merger consideration receivable/payable	0	2	0	2
Cash paid for business acquisitions	20	119	251	350
Less: Cash acquired	0	18	0	21
Business acquisitions, net of cash acquired	20	101	251	329
Leases:
Leased assets obtained in exchange for new operating lease liabilities	$ 46	$ 40	$ 115	$ 119

SUPPLEMENTAL CASH FLOW & OTHE_4

SUPPLEMENTAL CASH FLOW & OTHER DATA (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Aug. 31, 2020	Apr. 30, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020
Supplemental Cash Flow and Other Data [Line Items]
CARES Act, amount received from initial tranche		$ 65
CARES Act, amount received from secondary tranche	$ 73
Return of cash, CARES Act			$ 138
Other expense (income), net
Supplemental Cash Flow and Other Data [Line Items]
CARES Act proceeds recognized in the statement of operations					$ 65
Reversal of recognition of CARES Act proceeds				$ 65

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details)	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)claim	Oct. 31, 2020claim
Debt Instrument [Line Items]
Self-insurance reserves	$ 153,000,000	$ 138,000,000
Class action lawsuits | claim		2	2
Secured Receivables Credit Facility
Debt Instrument [Line Items]
Credit facility capacity	600,000,000
Letters of credit outstanding, amount	70,000,000
Secured Receivables Credit Facility | Letter of Credit
Debt Instrument [Line Items]
Credit facility capacity	100,000,000
Senior Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility capacity	750,000,000
Senior Unsecured Revolving Credit Facility | Letter of Credit
Debt Instrument [Line Items]
Credit facility capacity	150,000,000
Excludes general and professional liability claims
Loss Contingencies [Line Items]
Litigation reserves	$ 6,000,000	$ 1,000,000

BUSINESS SEGMENT INFORMATION (D

BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Percentage of net revenues	100.00%	100.00%	100.00%	100.00%
Total net revenues	$ 2,774	$ 2,786	$ 8,044	$ 6,435
Total operating income	652	718	1,845	1,176
Non-operating income (expense), net	2	35	252	(50)
Income before income taxes and equity in earnings of equity method investees	654	753	2,097	1,126
Income tax expense	(153)	(177)	(483)	(269)
Equity in earnings of equity method investees, net of taxes	26	15	53	33
Net income	527	591	1,667	890
Less: Net income attributable to noncontrolling interests	22	23	62	38
Net income attributable to Quest Diagnostics	505	568	1,605	852
Routine clinical testing services
Segment Reporting Information [Line Items]
Total net revenues	1,210	1,055	3,392	2,812
COVID-19 Testing Services
Segment Reporting Information [Line Items]
Total net revenues	709	965	2,048	1,571
Gene-based and esoteric testing services
Segment Reporting Information [Line Items]
Total net revenues	646	556	1,972	1,491
Anatomic pathology testing services
Segment Reporting Information [Line Items]
Total net revenues	138	133	408	343
All other services
Segment Reporting Information [Line Items]
Total net revenues	$ 71	$ 77	$ 224	$ 218
DIS business
Segment Reporting Information [Line Items]
Percentage of net revenues	97.00%	97.00%	97.00%	97.00%
Total net revenues	$ 2,703	$ 2,709	$ 7,820	$ 6,217
Total operating income	$ 713	$ 840	$ 2,026	$ 1,325
DIS business | Minimum
Segment Reporting Information [Line Items]
Percentage of net revenues	95.00%	95.00%	95.00%	95.00%
All other operating segments
Segment Reporting Information [Line Items]
Total net revenues	$ 71	$ 77	$ 224	$ 218
Total operating income	8	16	26	29
General corporate activities
Segment Reporting Information [Line Items]
Total operating income	$ (69)	$ (138)	$ (207)	$ (178)

REVENUE RECOGNITION (Details)

REVENUE RECOGNITION (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
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	97.00%	97.00%	97.00%	97.00%
Net accounts receivable	97.00%		97.00%		97.00%
DIS business | Healthcare Insurers
Segment Reporting Information [Line Items]
Percentage of net revenues	43.00%	35.00%	42.00%	36.00%
Net accounts receivable	35.00%		35.00%		34.00%
DIS business | Healthcare Insurers | Fee-for-service
Segment Reporting Information [Line Items]
Percentage of net revenues	41.00%	33.00%	39.00%	33.00%
DIS business | Healthcare Insurers | Capitated
Segment Reporting Information [Line Items]
Percentage of net revenues	2.00%	2.00%	3.00%	3.00%
DIS business | Government Payers
Segment Reporting Information [Line Items]
Percentage of net revenues	10.00%	10.00%	10.00%	12.00%
Net accounts receivable	6.00%		6.00%		6.00%
DIS business | Client Payers
Segment Reporting Information [Line Items]
Percentage of net revenues	31.00%	40.00%	33.00%	37.00%
Net accounts receivable	36.00%		36.00%		46.00%
DIS business | Patients
Segment Reporting Information [Line Items]
Percentage of net revenues	13.00%	12.00%	12.00%	12.00%
Net accounts receivable	20.00%		20.00%		11.00%
DIS business | Minimum
Segment Reporting Information [Line Items]
Percentage of net revenues	95.00%	95.00%	95.00%	95.00%
All other operating segments | DS Businesses
Segment Reporting Information [Line Items]
Percentage of net revenues	3.00%	3.00%	3.00%	3.00%
Net accounts receivable	3.00%		3.00%		3.00%

TAXES ON INCOME (Details)

TAXES ON INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Apr. 01, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effective income tax rate	23.40%	23.70%	23.10%	23.90%
Changes in reserves for uncertain tax positions	$ 6
Share-based compensation, excess tax benefit, amount	$ 6	$ 3	$ 15	$ 15
Effective tax rate on remeasurement in previously held interest		11.80%		11.80%
Equity interest in acquiree, remeasurement gain				$ 70
Disposed of by Sale | Q2 Solutions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effective income tax rate			17.60%
Percent of ownership interest sold					40.00%

SUBSEQUENT EVENT (Details)

SUBSEQUENT EVENT (Details) - Secured Receivables Credit Facility - USD ($)	Oct. 22, 2021	Sep. 30, 2021
Subsequent Event [Line Items]
Credit facility capacity		$ 600,000,000
Letter of Credit
Subsequent Event [Line Items]
Credit facility capacity		$ 100,000,000
Subsequent Event
Subsequent Event [Line Items]
Credit facility capacity	$ 600,000,000
Subsequent Event | Commercial Paper or LIBOR | Minimum
Subsequent Event [Line Items]
Interest rate	0.725%
Subsequent Event | Commercial Paper or LIBOR | Maximum
Subsequent Event [Line Items]
Interest rate	0.80%
Subsequent Event | Letter of Credit
Subsequent Event [Line Items]
Credit facility capacity	$ 100,000,000
Subsequent Event | Loan commitment maturing October 2022
Subsequent Event [Line Items]
Credit facility capacity	250,000,000
Subsequent Event | Loan commitment maturing October 2023
Subsequent Event [Line Items]
Credit facility capacity	$ 250,000,000