Quest Diagnostics (DGX) 10-Q 23 Oct 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 16, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
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	2019
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		134,697,086

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net revenues	$ 1,956	$ 1,889	$ 5,800	$ 5,692
Operating costs and expenses and other operating income:
Cost of services	1,264	1,222	3,773	3,691
Selling, general and administrative	362	354	1,108	1,068
Amortization of intangible assets	23	22	72	66
Other operating income, net	(6)	(13)	(21)	(14)
Total operating costs and expenses, net	1,643	1,585	4,932	4,811
Operating income	313	304	868	881
Other income (expense):
Interest expense, net	(44)	(41)	(133)	(124)
Other income, net	1	3	13	2
Total non-operating expenses, net	(43)	(38)	(120)	(122)
Income from continuing operations before income taxes and equity in earnings of equity method investees	270	266	748	759
Income tax expense	(62)	(48)	(175)	(142)
Equity in earnings of equity method investees, net of taxes	18	9	48	32
Income from continuing operations	226	227	621	649
Income from discontinued operations, net of taxes	0	0	20	0
Net income	226	227	641	649
Less: Net income attributable to noncontrolling interests	11	14	36	40
Net income attributable to Quest Diagnostics	215	213	605	609
Amounts attributable to Quest Diagnostics’ common stockholders:
Income from continuing operations	215	213	585	609
Income from discontinued operations, net of taxes	0	0	20	0
Net income attributable to Quest Diagnostics	$ 215	$ 213	$ 605	$ 609
Earnings per share attributable to Quest Diagnostics’ common stockholders - basic:
Income from continuing operations (in dollars per share)	$ 1.59	$ 1.56	$ 4.33	$ 4.46
Income from discontinued operations (in dollars per share)	0	0	0.15	0
Net income (in dollars per share)	1.59	1.56	4.48	4.46
Earnings per share attributable to Quest Diagnostics’ common stockholders - diluted:
Income from continuing operations (in dollars per share)	1.56	1.53	4.27	4.37
Income from discontinued operations (in dollars per share)	0	0	0.15	0
Net income (in dollars per share)	$ 1.56	$ 1.53	$ 4.42	$ 4.37
Weighted average common shares outstanding:
Basic (in Shares)	135	136	135	136
Diluted (in Shares)	137	139	136	139

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 226	$ 227	$ 641	$ 649
Other comprehensive income (loss):
Currency translation	(6)	(2)	(6)	(10)
Net change on available-for-sale debt securities, net of taxes	8	0	8	0
Net deferred gain on cash flow hedges, net of taxes	1	1	2	2
Other comprehensive income (loss)	3	(1)	4	(8)
Comprehensive income	229	226	645	641
Less: Comprehensive income attributable to noncontrolling interests	11	14	36	40
Comprehensive income attributable to Quest Diagnostics	$ 218	$ 212	$ 609	$ 601

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 434	$ 135
Accounts receivable, net of allowance for doubtful accounts of $15 as of both September 30, 2019 and December 31, 2018	1,117	1,012
Inventories	112	99
Prepaid expenses and other current assets	116	144
Total current assets	1,779	1,390
Property, plant and equipment, net	1,351	1,288
Operating lease right-of-use assets	508	0
Goodwill	6,617	6,563
Intangible assets, net	1,138	1,207
Investment in equity method investees	474	436
Other assets	152	119
Total assets	12,019	11,003
Liabilities and Stockholders' Equity
Accounts payable and accrued expenses	1,059	1,021
Current portion of long-term debt	805	464
Current portion of long-term operating lease liabilities	147	0
Total current liabilities	2,011	1,485
Long-term debt	3,188	3,429
Long-term operating lease liabilities	405	0
Other liabilities	685	745
Commitments and contingencies
Redeemable noncontrolling interest	76	77
Quest Diagnostics stockholders’ equity:
Common stock, par value $0.01 per share; 600 shares authorized as of both September 30, 2019 and December 31, 2018; 217 shares issued as of both September 30, 2019 and December 31, 2018	2	2
Additional paid-in capital	2,705	2,667
Retained earnings	7,992	7,602
Accumulated other comprehensive loss	(55)	(59)
Treasury stock, at cost; 82 shares as of both September 30, 2019 and December 31, 2018	(5,039)	(4,996)
Total Quest Diagnostics stockholders' equity	5,605	5,216
Noncontrolling interests	49	51
Total stockholders' equity	5,654	5,267
Total liabilities and stockholders' equity	$ 12,019	$ 11,003

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 15	$ 15
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)	217	217
Treasury stock (in shares)	82	82

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 641	$ 649
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	247	228
Provision for doubtful accounts	9	2
Deferred income tax provision	15	52
Stock-based compensation expense	44	53
Other, net	(44)	7
Changes in operating assets and liabilities:
Accounts receivable	(113)	(166)
Accounts payable and accrued expenses	80	51
Income taxes payable	9	(1)
Other assets and liabilities, net	7	30
Net cash provided by operating activities	895	905
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(56)	(219)
Capital expenditures	(228)	(232)
Increase in investments and other assets	(27)	(4)
Net cash used in investing activities	(311)	(455)
Cash flows from financing activities:
Proceeds from borrowings	1,484	1,630
Repayments of debt	(1,448)	(1,665)
Purchases of treasury stock	(153)	(150)
Exercise of stock options	98	95
Employee payroll tax withholdings on stock issued under stock-based compensation plans	(16)	(20)
Dividends paid	(215)	(198)
Distributions to noncontrolling interest partners	(39)	(41)
Contributions from noncontrolling interest partners	0	12
Other financing activities, net	4	13
Net cash used in financing activities	(285)	(324)
Net change in cash and cash equivalents and restricted cash	299	126
Cash and cash equivalents and restricted cash, beginning of period	135	137
Cash and cash equivalents and restricted cash, end of period	434	263
Cash and cash equivalents	135
Cash and cash equivalents and restricted cash, end of period	$ 135	$ 137

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, 2017		135
Balance, value at Dec. 31, 2017	$ 4,955	$ 2	$ 2,612	$ 7,138	$ (48)	$ (4,783)	$ 34
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	643			609			34
Other comprehensive income (loss), net of taxes	(8)				(8)
Dividends declared	(203)			(203)
Distributions to noncontrolling interest partners	(32)						(32)
Issuance of common stock under benefit plans	20		10			10
Stock-based compensation expense	53		49			4
Exercise of stock options, shares		2
Exercise of stock options, value	95		5			$ 90
Purchases of treasury stock, shares		(1)				(1.4)
Purchases of treasury stock, value	(150)					$ (150)
Contributions from noncontrolling interest partners	12						12
Reclassification of stranded tax effects resulting from enactment of the Tax Cut and Jobs Act	0			2	(2)
Balance, shares at Sep. 30, 2018		136
Balance, value at Sep. 30, 2018	5,365	$ 2	2,656	7,546	(58)	(4,829)	48
Balance, Value at Dec. 31, 2017	80
Redeemable Non-controlling Interest [Abstract]
Net income	6
Distributions to noncontrolling interest partners	(9)
Balance, Value at Sep. 30, 2018	77
Balance, shares at Jun. 30, 2018		136
Balance, value at Jun. 30, 2018	5,263	$ 2	2,633	7,401	(57)	(4,756)	40
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	224			213			11
Other comprehensive income (loss), net of taxes	(1)				(1)
Dividends declared	(68)			(68)
Distributions to noncontrolling interest partners	(11)						(11)
Issuance of common stock under benefit plans	7		4			3
Stock-based compensation expense	19		17			2
Exercise of stock options, shares		1
Exercise of stock options, value	24		2			22
Purchases of treasury stock, shares		(1)
Purchases of treasury stock, value	(100)					(100)
Contributions from noncontrolling interest partners	8						8
Balance, shares at Sep. 30, 2018		136
Balance, value at Sep. 30, 2018	5,365	$ 2	2,656	7,546	(58)	(4,829)	48
Balance, Value at Jun. 30, 2018	76
Redeemable Non-controlling Interest [Abstract]
Net income	3
Distributions to noncontrolling interest partners	(2)
Balance, Value at Sep. 30, 2018	77
Balance, shares at Dec. 31, 2018		135
Balance, value at Dec. 31, 2018	5,267	$ 2	2,667	7,602	(59)	(4,996)	51
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	637			605			32
Other comprehensive income (loss), net of taxes	4				4
Dividends declared	(215)			(215)
Distributions to noncontrolling interest partners	(34)						(34)
Issuance of common stock under benefit plans	19		7			12
Stock-based compensation expense	44		43			1
Exercise of stock options, shares		2
Exercise of stock options, value	98					$ 94
Purchases of treasury stock, shares		(2)				(1.6)
Purchases of treasury stock, value	(150)					$ (150)
Balance, shares at Sep. 30, 2019		135
Balance, value at Sep. 30, 2019	5,654	$ 2	2,705	7,992	(55)	(5,039)	49
Balance, Value at Dec. 31, 2018	77
Redeemable Non-controlling Interest [Abstract]
Net income	4
Distributions to noncontrolling interest partners	(5)
Balance, Value at Sep. 30, 2019	76
Balance, shares at Jun. 30, 2019		135
Balance, value at Jun. 30, 2019	5,509	$ 2	2,686	7,849	(58)	(5,020)	50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	225			215			10
Other comprehensive income (loss), net of taxes	3				3
Dividends declared	(72)			(72)
Distributions to noncontrolling interest partners	(11)						(11)
Issuance of common stock under benefit plans	6		3			3
Stock-based compensation expense	12		12
Exercise of stock options, shares		1
Exercise of stock options, value	32		4			28
Purchases of treasury stock, shares		(1)
Purchases of treasury stock, value	(50)					(50)
Balance, shares at Sep. 30, 2019		135
Balance, value at Sep. 30, 2019	5,654	$ 2	$ 2,705	$ 7,992	$ (55)	$ (5,039)	$ 49
Balance, Value at Jun. 30, 2019	76
Redeemable Non-controlling Interest [Abstract]
Net income	1
Distributions to noncontrolling interest partners	(1)
Balance, Value at Sep. 30, 2019	$ 76

DESCRIPTION OF BUSINESS

DESCRIPTION OF BUSINESS	9 Months Ended
	Sep. 30, 2019
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, 2019
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 2018 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2018 , 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 consolidated financial statements contained in the Company’s 2018 Annual Report on Form 10-K except for the impact of the adoption of new accounting standards discussed under New Accounting Pronouncements. 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, 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, 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. 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 Pronouncements Adoption of New Accounting Standards On January 1, 2019, the Company adopted a new accounting standard issued by the Financial Accounting Standards Board ("FASB") on accounting for leases using the modified retrospective method. This new accounting standard requires a lessee to recognize an asset and liability for most leases on its balance sheet. The Company elected the optional transition method that allowed for a cumulative-effect adjustment to the opening balance of retained earnings recorded on January 1, 2019 and did not restate previously reported results in the comparative periods. The Company also elected the package of practical expedients, which among other things, allowed it to carry forward its historical lease classification. As a result of adoption of the new standard, the Company recorded operating lease assets and lease liabilities of approximately $500 million and $550 million , respectively as of January 1, 2019. The operating lease liability was determined based on the present value of the remaining minimum rental payments and the operating lease asset was determined based on the value of the lease liability, adjusted for the deferred rent balances of approximately $50 million , which were previously included in accounts payable and accrued expenses as well as other liabilities. Accounting for the Company's finance leases remains substantially unchanged. The adoption of the new standard did not materially impact the Company's consolidated results of operations or cash flows. In addition, the adoption of this new accounting standard resulted in increased qualitative and quantitative disclosures regarding the amount, timing, and uncertainty of cash flows arising from leases. For further details, see Note 9. On January 1, 2019, the Company adopted a new accounting standard issued by the FASB that includes the overnight index swap rate based on the Secured Overnight Financing Rate as an additional benchmark interest rate for hedge accounting purposes. Adoption of this new accounting standard applies prospectively to new or redesignated hedges entered into after the adoption date and, therefore, did not have an impact on the Company's existing interest rate swap agreements. New Accounting Standards To Be Adopted In August 2018, the FASB issued an Accounting Standard Update (“ASU”) that aligns the requirements for deferring implementation costs incurred in a cloud computing arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This ASU is effective for the Company in the first quarter of 2020 with early adoption permitted and can be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company is currently assessing the impact of the adoption of this ASU on the Company’s results of operations, financial position and cash flows.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2019
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: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Amounts attributable to Quest Diagnostics’ common stockholders: Income from continuing operations $ 215 $ 213 $ 585 $ 609 Income from discontinued operations, net of taxes — — 20 — Net income attributable to Quest Diagnostics’ common stockholders $ 215 $ 213 $ 605 $ 609 Income from continuing operations $ 215 $ 213 $ 585 $ 609 Less: Earnings allocated to participating securities 1 1 2 2 Earnings available to Quest Diagnostics’ common stockholders – basic and diluted $ 214 $ 212 $ 583 $ 607 Weighted average common shares outstanding – basic 135 136 135 136 Effect of dilutive securities: Stock options and performance share units 2 3 1 3 Weighted average common shares outstanding – diluted 137 139 136 139 Earnings per share attributable to Quest Diagnostics’ common stockholders - basic: Income from continuing operations $ 1.59 $ 1.56 $ 4.33 $ 4.46 Income from discontinued operations — — 0.15 — Net income $ 1.59 $ 1.56 $ 4.48 $ 4.46 Earnings per share attributable to Quest Diagnostics’ common stockholders – diluted: Income from continuing operations $ 1.56 $ 1.53 $ 4.27 $ 4.37 Income from discontinued operations — — 0.15 — Net income $ 1.56 $ 1.53 $ 4.42 $ 4.37 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, 2019 2018 2019 2018 Stock options 2 2 3 2

RESTRUCTURING ACTIVITIES

RESTRUCTURING ACTIVITIES	9 Months Ended
	Sep. 30, 2019
Restructuring and Related Activities [Abstract]
RESTRUCTURING ACTIVITIES	RESTRUCTURING ACTIVITIES Invigorate Program The Company is committed to a program called Invigorate which is designed to reduce its cost structure and improve performance. Invigorate consists of several flagship programs, with structured plans in each, to drive savings and improve performance across the customer value chain. These flagship programs include: organization excellence; information technology excellence; procurement excellence; service excellence; lab excellence; and billing excellence. In addition to these programs, the Company identified key themes to change how it operates including reducing denials and patient concessions; further digitizing the business; standardization and automation; and optimization initiatives in the areas of lab network and patient service center network. The Invigorate program is intended to partially offset reimbursement pressures and labor and benefit cost increases; free up additional resources to invest in science, innovation and other growth initiatives; and enable the Company to improve service quality and operating profitability. Restructuring Charges The following table provides a summary of the Company's pre-tax restructuring charges for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Employee separation costs $ — $ 4 $ (3 ) $ 19 Facility-related costs — — — 4 Total restructuring charges $ — $ 4 $ (3 ) $ 23 The restructuring activity recorded in the nine months ended September 30, 2019 represents a release of the liability relating to restructuring charges recorded in prior periods, which were determined to no longer be required. Of the total restructuring release recorded in the nine months ended September 30, 2019 , $(1) million and $(2) million were recorded in cost of services and selling, general and administrative expenses, respectively. The restructuring charges incurred for the three and nine months ended September 30, 2018 were primarily associated with various workforce reduction initiatives as the Company continued to simplify and restructure its organization. Of the total restructuring charges incurred during the three months ended September 30, 2018 , $2 million was recorded in each of cost of services and selling, general and administrative expenses. Of the total restructuring charges incurred during the nine months ended September 30, 2018 , $9 million and $14 million were recorded in cost of services and selling, general and administrative expenses, respectively. Charges for all periods presented were primarily recorded in the Company's DIS business. The restructuring liability as of September 30, 2019 and December 31, 2018 , which is included in accounts payable and accrued expenses, was $11 million and $38 million , respectively.

BUSINESS ACQUISITIONS

BUSINESS ACQUISITIONS	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
BUSINESS ACQUISITIONS	BUSINESS ACQUISITIONS On February 11, 2019, the Company completed its acquisition of certain assets of the clinical laboratory services business of Boyce & Bynum Pathology Laboratories, P.C. ("Boyce & Bynum") in an all cash transaction for $61 million , which consisted of cash consideration of $55 million and contingent consideration initially estimated at $6 million . The contingent consideration arrangement is dependent upon the achievement of certain testing volume benchmarks. During the third quarter of 2019, the liability was reduced to $0 as a result of updated testing volume forecasts for the earn-out period compared to the testing volume target included in the contingent consideration arrangement, resulting in a $6 million gain recorded in other operating income, net. Based on the preliminary purchase price allocation, the assets acquired principally consist of $41 million of goodwill (of which $35 million is currently tax deductible) and $20 million of customer-related intangible assets. The intangible assets will be amortized over a useful life of 15 years. For further details regarding the fair value of the contingent consideration, see Note 6. On November 6, 2018, the Company completed the acquisition of all of the operations of the U.S. laboratory service business of Oxford Immunotec, Inc. ("Oxford") and recorded the assets acquired and liabilities assumed based on a preliminary purchase price allocation. In September 2019, the Company finalized its purchase price allocation and recorded a $13 million increase to goodwill, an $11 million decrease to intangible assets and a $2 million adjustment to other assets and liabilities. These adjustments did not have a material impact on the Company's consolidated results of operations. The acquisitions were 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 acquisitions are 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 entities 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 acquisitions has been allocated to the Company's DIS business. For further details regarding business segment information, see Note 14 . For details regarding the Company's 2018 acquisitions, see Note 6 to the consolidated financial statements in the Company's 2018 Annual Report on Form 10-K.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2019
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, 2019 Total Level 1 Level 2 Level 3 Assets: Trading securities $ 55 $ 55 $ — $ — Cash surrender value of life insurance policies 41 — 41 — Available-for-sale debt securities 12 — — 12 Forward-starting interest rate swaps 2 — 2 — Total $ 110 $ 55 $ 43 $ 12 Liabilities: Deferred compensation liabilities $ 104 $ — $ 104 $ — Fixed-to-variable interest rate swaps 17 — 17 — Contingent consideration 7 — — 7 Total $ 128 $ — $ 121 $ 7 Redeemable noncontrolling interest $ 76 $ — $ — $ 76 Basis of Fair Value Measurements December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Trading securities $ 53 $ 53 $ — $ — Cash surrender value of life insurance policies 34 — 34 — Total $ 87 $ 53 $ 34 $ — Liabilities: Deferred compensation liabilities $ 96 $ — $ 96 $ — Fixed-to-variable interest rate swaps 93 — 93 — Contingent consideration 14 — — 14 Total $ 203 $ — $ 189 $ 14 Redeemable noncontrolling interest $ 77 $ — $ — $ 77 A detailed description regarding the Company's fair value measurements is contained in Note 8 to the consolidated financial statements in the Company's 2018 Annual Report on Form 10-K. The Company offers certain employees the opportunity to participate in a non-qualified supplemental deferred compensation plan. A participant's deferrals, together with Company matching credits, are invested in a variety of participant-directed stock and bond mutual funds that are classified as trading securities. The trading securities are classified within Level 1 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 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 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 available-for-sale debt securities are measured at fair value using discounted 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. Significant inputs include cash flows projections and a discount rate. The fair value measurements of the Company's fixed-to-variable interest rate swaps and forward-starting interest rate swaps classified within Level 2 of the fair value hierarchy are model-derived valuations as of a given date in which all significant inputs are observable in active markets including certain financial information and certain assumptions regarding past, present and future market conditions. In connection with previous business acquisitions, the Company has contingent consideration obligations that are to be paid based on the achievement of certain testing volume or revenue benchmarks. These contingent consideration liabilities are measured at fair value using an option-pricing method and are classified within Level 3 of the fair value hierarchy as the fair value is determined based on significant inputs that are not observable. Significant inputs include management’s estimate of volume or revenue and other market inputs including comparable company revenue volatility and a discount rate. A summary of the significant inputs is as follows: Business Acquisition Fair Value of Contingent Consideration Benchmark Comparable Company Revenue Volatility Discount rate Maximum Contingent Consideration Payment Certain assets of the clinical and anatomic pathology laboratory business of Shiel Holdings, LLC in December 2017 $ 7 Volume 6.9% 4.5% $ 15 ReproSource, Inc. in September 2018 $ — Revenue 8.5% 6.5% $ 10 Certain assets of the clinical laboratory services business of Boyce & Bynum in February 2019 $ — Volume 8.0% 7.2% $ 25 For further details regarding the Company's acquisitions, see Note 6 to the consolidated financial statements in the Company's 2018 Annual Report on Form 10-K and Note 5 to the interim unaudited consolidated financial statements. The following table provides a reconciliation of the beginning and ending balances of liabilities using significant unobservable inputs (Level 3): Contingent Consideration Balance, December 31, 2018 $ 14 Purchases, additions and issuances 6 Settlements (1 ) Total gains/losses included in earnings - realized/unrealized (12 ) Balance, September 30, 2019 $ 7 The $12 million net gain included in earnings associated with the change in the fair value of contingent consideration for the nine months ended September 30, 2019 is reported in other operating income, net. 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, 2019 , the redeemable noncontrolling interest was presented at its fair value. The fair value measurement of the redeemable noncontrolling interest is classified within Level 3 of the fair value hierarchy because the fair value is based on a discounted cash flow analysis that takes into account, among other items, the joint venture's expected future cash flows, long term growth rates, and a discount rate commensurate with economic risk. The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable and accrued expenses approximate fair value based on the short maturities of these instruments. As of September 30, 2019 and December 31, 2018 , the fair value of the Company’s debt was estimated at $4.3 billion and $4.0 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, 2019
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, 2019 and for the year ended December 31, 2018 were as follows: September 30, December 31, Balance, beginning of period $ 6,563 $ 6,335 Goodwill acquired during the period 42 228 Adjustments to goodwill 12 — Balance, end of period $ 6,617 $ 6,563 Principally all of the Company’s goodwill as of September 30, 2019 and December 31, 2018 was associated with its DIS business. For the nine months ended September 30, 2019 , goodwill acquired during the period was primarily associated with the acquisition of certain assets of the clinical laboratory services business of Boyce & Bynum (see Note 5). For the year ended December 31, 2018 , goodwill acquired was principally associated with the acquisitions of Oxford, Mobile Medical Examination Services, LLC., ReproSource, Inc. and the outreach laboratory service business of Cape Cod Healthcare, Inc. For the nine months ended September 30, 2019 , adjustments to goodwill primarily related to finalization of the purchase price allocation for Oxford (see Note 5). For details regarding the Company's 2018 acquisitions, see Note 6 to the consolidated financial statements in the Company's 2018 Annual Report on Form 10-K. Intangible assets at September 30, 2019 and December 31, 2018 consisted of the following: Weighted Average Amortization Period (in years) September 30, 2019 December 31, 2018 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Amortizing intangible assets: Customer-related 18 $ 1,359 $ (536 ) $ 823 $ 1,355 $ (478 ) $ 877 Non-compete agreements 9 3 (2 ) 1 3 (2 ) 1 Technology 17 104 (54 ) 50 104 (50 ) 54 Other 9 110 (82 ) 28 114 (75 ) 39 Total 17 1,576 (674 ) 902 1,576 (605 ) 971 Intangible assets not subject to amortization: Trade names 235 — 235 235 — 235 Other 1 — 1 1 — 1 Total intangible assets $ 1,812 $ (674 ) $ 1,138 $ 1,812 $ (605 ) $ 1,207 The estimated amortization expense related to amortizable intangible assets for each of the five succeeding fiscal years and thereafter as of September 30, 2019 is as follows: Year Ending December 31, Remainder of 2019 $ 24 2020 96 2021 89 2022 86 2023 85 2024 81 Thereafter 441 Total $ 902

DEBT

DEBT	9 Months Ended
	Sep. 30, 2019
Debt Instruments [Abstract]
DEBT	DEBT Long-term debt (including finance lease obligations) as of September 30, 2019 and December 31, 2018 consisted of the following: September 30, 2019 December 31, Secured Receivables Credit Facility (3.39% at December 31, 2018) $ — $ 160 2.70% Senior Notes due April 2019 — 300 4.75% Senior Notes due January 2020 501 507 2.50% Senior Notes due March 2020 300 300 4.70% Senior Notes due April 2021 554 557 4.25% Senior Notes due April 2024 310 299 3.50% Senior Notes due March 2025 600 562 3.45% Senior Notes due June 2026 494 469 4.20% Senior Notes due June 2029 499 — 6.95% Senior Notes due July 2037 175 175 5.75% Senior Notes due January 2040 244 244 4.70% Senior Notes due March 2045 300 300 Other 35 37 Debt issuance costs (19 ) (17 ) Total long-term debt 3,993 3,893 Less: Current portion of long-term debt 805 464 Total long-term debt, net of current portion $ 3,188 $ 3,429 2019 Senior Notes Offering In March 2019, the Company completed a senior unsecured notes offering (the “2019 Senior Notes”), consisting of $500 million aggregate principal amount of 4.20% senior notes due June 2029, which were issued at an original issue discount of $1 million . The 2019 Senior Notes are unsecured obligations of the Company that rank equally with the Company's other senior unsecured obligations. The 2019 Senior Notes do not have a sinking fund requirement. The Company incurred $5 million of debt issuance costs associated with the 2019 Senior Notes, which is included as a reduction to the carrying amount of long-term debt and is being amortized over the term of the related debt. The net proceeds from the 2019 Senior Notes were used to repay in full the outstanding indebtedness under the Company's Senior Notes due April 1, 2019, to repay outstanding indebtedness under the secured receivables credit facility and for general corporate purposes. Secured Receivables Credit Facility During the nine months ended September 30, 2019 , there were $985 million in cumulative borrowings under the secured receivables credit facility primarily associated with working capital requirements as well as the funding of the Company's 2019 business acquisition. During the nine months ended September 30, 2019 , there were $1,145 million in repayments under the secured receivables credit facility. Maturities of Long-Term Debt As of September 30, 2019 , long-term debt matures as follows: Year Ending December 31, Remainder of 2019 $ 1 2020 803 2021 553 2022 3 2023 1 Thereafter 2,649 Total maturities of long-term debt 4,010 Unamortized discount (9 ) Debt issuance costs (19 ) Fair value basis adjustments attributable to hedged debt 11 Total long-term debt 3,993 Current portion of long-term debt 805 Total long-term debt, net of current portion $ 3,188

LEASES

LEASES	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
LEASES	LEASES The Company determines if an arrangement is or contains a lease at contract inception. The Company leases office space, patient service centers, clinical laboratories, warehouses, logistic hubs and equipment primarily through operating leases with a limited number of finance leases. A right-of-use asset, representing the underlying asset during the lease term, and a lease liability, representing the payment obligation arising from the lease, are recognized on the balance sheet at lease commencement based on the present value of the payment obligation. For operating leases, expense is recognized on a straight-line basis over the lease term. For finance leases, interest expense on the lease liability is recognized using the effective interest method and amortization of the right-of-use asset is recognized on a straight-line basis over the shorter of the estimated useful life of the asset or the lease term. Short-term leases with an initial term of 12 months or less are not recorded on the balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company primarily uses its incremental borrowing rate in determining the present value of lease payments as the Company's leases generally do not provide an implicit rate. The Company has lease agreements with (i) right-of-use asset payments and (ii) non-lease components (i.e. payments related to maintenance fees, utilities, etc,) which have generally been combined and accounted for as a single lease component. The Company's leases have remaining terms of less than 1 year to 15 years , some of which include options to extend the leases for up to 15 years . The Company's lease terms may include renewal options that are reasonably certain to be exercised and termination options that are reasonably certain not to be exercised. Certain leases also include options to purchase the leased property. Certain of the Company's lease agreements include rental payments adjusted periodically for inflation or a market rate which are included in the lease liabilities. Leases Balance Sheet Classification September 30, 2019 Assets Operating Operating lease right-of-use assets $ 508 Finance Property, plant and equipment, net (a) 37 Total lease assets $ 545 Liabilities Current: Operating Current portion of long-term operating lease liabilities $ 147 Finance Current portion of long-term debt 3 Non-current: Operating Long-term operating lease liabilities 405 Finance Long-term debt 31 Total lease liabilities $ 586 (a) Finance lease assets were recorded net of accumulated amortization of $23 million as of September 30, 2019 . Components of lease cost for the three and nine months ended September 30, 2019 were as follows: Lease cost Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Operating lease cost (a) $ 75 $ 221 Finance lease cost: Amortization of leased assets 1 5 Interest on lease liabilities — 2 Net lease cost $ 76 $ 228 (a) Includes short-term leases and variable lease costs (primarily maintenance fees and utilities related to real estate leases and certain equipment-related and vehicle-related costs) of $32 million and $90 million for the three and nine months ended September 30, 2019 , respectively. Rental expense for real estate, laboratory equipment and vehicles under operating leases amounted to $55 million and $167 million for the three and nine months ended September 30, 2018 , respectively. The maturity of the Company's lease liabilities as of September 30, 2019 is as follows: Maturity of lease liabilities Operating leases Finance leases Total Remainder of 2019 $ 32 $ 1 $ 33 2020 155 6 161 2021 118 5 123 2022 93 5 98 2023 74 3 77 Thereafter 138 35 173 Total lease payments 610 55 665 Less: Interest (a) 58 21 79 Present value of lease liabilities $ 552 $ 34 $ 586 (a) Primarily calculated using the Company's incremental borrowing rate. Minimum rental commitments under noncancelable operating leases, primarily real estate, in effect as of December 31, 2018 are as follows: Year Ending December 31, 2019 $ 181 2020 143 2021 106 2022 79 2023 60 Thereafter 122 Minimum lease payments $ 691 Lease term and discount rate as of September 30, 2019 were as follows: Lease term and discount rate Weighted-average remaining lease term (years): Operating leases 5 Finance leases 12 Weighted-average discount rate: Operating leases 3.3 % Finance leases 8.7 % See Note 12 for cash flow information on cash paid for amounts included in the measurement of lease liabilities, leased assets obtained in exchange for new operating lease liabilities, and leased assets obtained in exchange for new finance lease liabilities for the three and nine months ended September 30, 2019 .
LEASES	LEASES The Company determines if an arrangement is or contains a lease at contract inception. The Company leases office space, patient service centers, clinical laboratories, warehouses, logistic hubs and equipment primarily through operating leases with a limited number of finance leases. A right-of-use asset, representing the underlying asset during the lease term, and a lease liability, representing the payment obligation arising from the lease, are recognized on the balance sheet at lease commencement based on the present value of the payment obligation. For operating leases, expense is recognized on a straight-line basis over the lease term. For finance leases, interest expense on the lease liability is recognized using the effective interest method and amortization of the right-of-use asset is recognized on a straight-line basis over the shorter of the estimated useful life of the asset or the lease term. Short-term leases with an initial term of 12 months or less are not recorded on the balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company primarily uses its incremental borrowing rate in determining the present value of lease payments as the Company's leases generally do not provide an implicit rate. The Company has lease agreements with (i) right-of-use asset payments and (ii) non-lease components (i.e. payments related to maintenance fees, utilities, etc,) which have generally been combined and accounted for as a single lease component. The Company's leases have remaining terms of less than 1 year to 15 years , some of which include options to extend the leases for up to 15 years . The Company's lease terms may include renewal options that are reasonably certain to be exercised and termination options that are reasonably certain not to be exercised. Certain leases also include options to purchase the leased property. Certain of the Company's lease agreements include rental payments adjusted periodically for inflation or a market rate which are included in the lease liabilities. Leases Balance Sheet Classification September 30, 2019 Assets Operating Operating lease right-of-use assets $ 508 Finance Property, plant and equipment, net (a) 37 Total lease assets $ 545 Liabilities Current: Operating Current portion of long-term operating lease liabilities $ 147 Finance Current portion of long-term debt 3 Non-current: Operating Long-term operating lease liabilities 405 Finance Long-term debt 31 Total lease liabilities $ 586 (a) Finance lease assets were recorded net of accumulated amortization of $23 million as of September 30, 2019 . Components of lease cost for the three and nine months ended September 30, 2019 were as follows: Lease cost Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Operating lease cost (a) $ 75 $ 221 Finance lease cost: Amortization of leased assets 1 5 Interest on lease liabilities — 2 Net lease cost $ 76 $ 228 (a) Includes short-term leases and variable lease costs (primarily maintenance fees and utilities related to real estate leases and certain equipment-related and vehicle-related costs) of $32 million and $90 million for the three and nine months ended September 30, 2019 , respectively. Rental expense for real estate, laboratory equipment and vehicles under operating leases amounted to $55 million and $167 million for the three and nine months ended September 30, 2018 , respectively. The maturity of the Company's lease liabilities as of September 30, 2019 is as follows: Maturity of lease liabilities Operating leases Finance leases Total Remainder of 2019 $ 32 $ 1 $ 33 2020 155 6 161 2021 118 5 123 2022 93 5 98 2023 74 3 77 Thereafter 138 35 173 Total lease payments 610 55 665 Less: Interest (a) 58 21 79 Present value of lease liabilities $ 552 $ 34 $ 586 (a) Primarily calculated using the Company's incremental borrowing rate. Minimum rental commitments under noncancelable operating leases, primarily real estate, in effect as of December 31, 2018 are as follows: Year Ending December 31, 2019 $ 181 2020 143 2021 106 2022 79 2023 60 Thereafter 122 Minimum lease payments $ 691 Lease term and discount rate as of September 30, 2019 were as follows: Lease term and discount rate Weighted-average remaining lease term (years): Operating leases 5 Finance leases 12 Weighted-average discount rate: Operating leases 3.3 % Finance leases 8.7 % See Note 12 for cash flow information on cash paid for amounts included in the measurement of lease liabilities, leased assets obtained in exchange for new operating lease liabilities, and leased assets obtained in exchange for new finance lease liabilities for the three and nine months ended September 30, 2019 .

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2019
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, treasury 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 entered into interest rate swaps. 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. In February 2019, the Company entered into interest rate lock agreements with several financial institutions for a total notional amount of $250 million , which were accounted for as cash flow hedges. These agreements were entered into to hedge a portion of the Company's interest rate exposure associated with variability in future cash flows attributable to changes in the ten-year treasury rates related to the expected issuance of the 2019 Senior Notes. In connection with the issuance of the 2019 Senior Notes in March 2019, these agreements were settled, and the Company paid $1 million . These losses are deferred in stockholders' equity, net of taxes, as a component of accumulated other comprehensive loss, and amortized as an adjustment to interest expense, net over the term of the 2019 Senior Notes. During the third quarter of 2019, the Company entered into forward-starting interest rate swap agreements with several financial institutions for a total notional amount of $125 million . The swap agreements, which are accounted for as cash flow hedges, were entered into in order to hedge a portion of the Company's interest rate exposure associated with variability in future cash flows attributable to changes in interest rates over a ten-year period related to an anticipated issuance of debt during 2020. The new debt will replace certain senior notes that are maturing at such time. Prior to their maturity or settlement, the forward-starting interest rate swaps will be recognized as either an asset or liability, measured at their fair value. To the extent they are effective, gains and losses related to recording the forward-starting interest rate swap agreements at fair value will be deferred in stockholders' equity, net of taxes, as a component of accumulated other comprehensive loss. Subsequent to the issuance of the debt and settlement of the forward-starting interest rate swaps, the deferred gain/loss will be amortized as an adjustment to interest expense, net over the term of such debt. The total net loss, net of taxes, recognized in accumulated other comprehensive loss, related to the Company's cash flow hedges was $7 million and $9 million as of September 30, 2019 and December 31, 2018 , respectively. The net amount of deferred losses on cash flow hedges that is expected to be reclassified from accumulated other comprehensive loss into interest expense, net within the next twelve months is $1 million . Interest Rate Derivatives – Fair Value Hedges The Company maintains various fixed-to-variable interest rate swaps to convert a portion of the Company's long-term debt into variable interest rate debt. A summary of the notional amounts of these interest rate swaps as of September 30, 2019 and December 31, 2018 was as follows: Notional Amount Debt Instrument September 30, 2019 December 31, 2018 4.25% Senior Notes due April 2024 $ 250 $ 250 3.50% Senior Notes due March 2025 600 600 3.45% Senior Notes due June 2026 350 350 $ 1,200 $ 1,200 The fixed-to-variable interest rate swap agreements in the table above have variable interest rates ranging from one-month LIBOR plus 2.2% to one-month LIBOR plus 3.0% . As of September 30, 2019 and December 31, 2018 , the following amounts were recorded on the consolidated balance sheet related to cumulative basis adjustments for fair value hedges included in the carrying amount of long-term debt: Carrying Amount of Hedged Long-Term Debt Hedge Accounting Basis Adjustment (a) Carrying Amount of Hedged Long-Term Debt Hedge Accounting Basis Adjustment (a) Balance Sheet Classification September 30, 2019 September 30, 2019 December 31, 2018 December 31, 2018 Long-term debt $ 1,198 $ 11 $ 1,125 $ (53 ) (a) The balance includes $28 million and $40 million of remaining unamortized hedging adjustment on a discontinued relationship as of September 30, 2019 and December 31, 2018 , respectively. The following table presents the effect of fair value hedge accounting on the statement of operations for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 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 $ 1 $ 3 $ 13 $ 2 Gain (loss) on fair value hedging relationships: Hedged items (Long-term debt) $ (20 ) $ 10 $ (76 ) $ 42 Derivatives designated as hedging instruments $ 20 $ (10 ) $ 76 $ (42 ) A summary of the fair values of derivative instruments in the consolidated balance sheets was as follows: September 30, 2019 December 31, 2018 Derivatives Designated as Hedging Instruments Balance Sheet Classification Fair Value Balance Sheet Classification Fair Value Forward-starting interest rate swaps Prepaid expenses and other current assets $ 2 Prepaid expenses and other current assets $ — Fixed-to-variable interest rate swaps Other liabilities $ 17 Other liabilities $ 93 A detailed description regarding the Company's use of derivative financial instruments is contained in Note 15 to the consolidated financial statements in the Company's 2018

STOCKHOLDERS_ EQUITY AND REDEEM

STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST	9 Months Ended
	Sep. 30, 2019
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 Income (Loss) by Component Comprehensive income (loss) includes: • Foreign currency translation adjustments; • Net deferred gain on cash flow hedges, which represents 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 10 ); and • Net change on available-for-sale debt securities, which represents unrealized holding gains, net of taxes on available-for-sale debt securities. For the three and nine months ended September 30, 2019 and 2018 , the tax effects related to the deferred gains/losses on cash flow hedges and net change on 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. Dividend Program During each of the first three quarters of 2019, the Company's Board of Directors declared a quarterly cash dividend of $0.53 per common share. During each of the first three quarters of 2018, the Company's Board of Directors declared a quarterly cash dividend of $0.50 per common share. During the fourth quarter of 2018, the Company's Board of Directors declared a quarterly cash dividend of $0.53 per common share. Share Repurchase Program As of September 30, 2019 , $442 million remained available under the Company’s share repurchase authorizations. The share repurchase authorization has no set expiration or termination date. Share Repurchases For the nine months ended September 30, 2019 , the Company repurchased 1.6 million shares of its common stock for $150 million . For the nine months ended September 30, 2018 , the Company repurchased 1.4 million shares of its common stock for $150 million . Shares Reissued from Treasury Stock For the nine months ended September 30, 2019 and 2018 , the Company reissued 1.8 million shares and 1.7 million shares, respectively, from treasury stock for shares issued under the Employee Stock Purchase Plan and stock option plans. For details regarding the Company's stock ownership and compensation plans, see Note 17 to the consolidated financial statements in the Company's 2018 Annual Report on Form 10-K. Redeemable Noncontrolling Interest In connection with the sale of an 18.9% noncontrolling interest in a subsidiary to UMass on July 1, 2015, the Company granted UMass the right to require the Company to purchase all of its interest in the subsidiary at fair value commencing July 1, 2020. The subsidiary performs diagnostic information services in a defined territory within the state of Massachusetts. Since the redemption of the noncontrolling interest is outside of the Company's control, it has been presented outside of stockholders' equity at the greater of its carrying amount or its fair value. The Company records changes in the fair value of the noncontrolling interest immediately as they occur. As of September 30, 2019 , 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, 2019
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, 2019 and 2018 was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Depreciation expense $ 59 $ 55 $ 175 $ 162 Amortization expense 23 22 72 66 Depreciation and amortization expense $ 82 $ 77 $ 247 $ 228 Interest expense $ (45 ) $ (42 ) $ (136 ) $ (126 ) Interest income 1 1 3 2 Interest expense, net $ (44 ) $ (41 ) $ (133 ) $ (124 ) Interest paid $ 58 $ 28 $ 149 $ 114 Income taxes paid $ 65 $ 29 $ 148 $ 70 Accounts payable associated with capital expenditures $ 24 $ 13 $ 24 $ 13 Dividends payable $ 72 $ 68 $ 72 $ 68 Businesses acquired: Fair value of assets acquired $ — $ 59 $ 61 $ 242 Fair value of liabilities assumed — — — 1 Fair value of net assets acquired — 59 61 241 Merger consideration paid (payable), net — (5 ) (5 ) (17 ) Cash paid for business acquisitions — 54 56 224 Less: Cash acquired — — — 5 Business acquisitions, net of cash acquired $ — $ 54 $ 56 $ 219 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Leases: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 45 $ 135 Operating cash flows from finance leases $ — $ 2 Financing cash flows from finance leases $ 1 $ 3 Leased assets obtained in exchange for new operating lease liabilities $ 38 $ 116 Leased assets obtained in exchange for new finance lease liabilities (a) $ 1 $ — $ 1 $ 1 (a) For the three and nine months ended September 30, 2018, leased assets obtained in exchange for new finance lease liabilities reflects information prior to the adoption of the new accounting standard related to accounting for leases. See Note 2 for further details on the adoption of the new accounting standard.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2019
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 secured receivables credit facility and $150 million under its senior unsecured revolving credit facility. For further discussion regarding the Company's secured receivables credit facility and senior unsecured revolving credit facility, see Note 14 to the consolidated financial statements in the Company's 2018 Annual Report on Form 10-K and Note 8 to the interim unaudited consolidated financial statements. In support of its risk management program, to ensure the Company’s performance or payment to third parties, $71 million in letters of credit under the secured receivables credit facility were outstanding as of September 30, 2019 . The letters of credit primarily represent 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, including leases that were entered into by certain predecessor companies of a subsidiary prior to the Company's acquisition of the subsidiary. No liability has been recorded for any of these potential contingent obligations. For further details, see Note 18 to the consolidated financial statements in the Company’s 2018 Annual Report on Form 10-K. Legal Matters AMCA Data Security Incident On June 3, 2019, the Company reported that Retrieval-Masters Creditors Bureau, Inc./American Medical Collection Agency (“AMCA”), informed the Company and Optum360 LLC, which provides revenue management services to the Company, about a data security incident involving AMCA (the “AMCA Data Security Incident”). AMCA (which provided debt collection services for Optum360) informed the Company and Optum360 that AMCA had learned that an unauthorized user had access to AMCA’s system between August 1, 2018 and March 30, 2019. 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 has also informed us 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. To date, approximately 39 lawsuits related to the AMCA Data Security Incident have been filed against the Company, most of which name other defendants, in federal courts in a number of districts and in state courts. Most of the cases are putative class actions in which the plaintiffs, who purport to represent various classes of consumers, assert a variety of common law and statutory claims in connection with the AMCA Data Security Incident and most of them have been transferred to and consolidated in the U.S. District Court for New Jersey by the U.S. Judicial Panel on Multidistrict Litigation. 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 Attorneys General offices from numerous states and the District of Columbia and certain U.S. senators. The Company has insurance coverage rights in place for certain potential costs and liabilities related to the AMCA Data Security Incident; this insurance coverage is limited in amount and subject to a deductible. While management believes it is reasonably possible that the Company may incur losses associated with these proceedings and investigations, 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. 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, including, among other matters, operational matters, which may result in adverse judgments, settlements, fines, penalties, injunctions or other relief. The number of these reviews, investigations and proceedings has increased in recent years with regard to many firms in the healthcare services industry, including the Company. 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 practices based on the qui tam provisions of the Civil 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 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, 2019 , the Company does not believe that material losses related to legal matters are probable. Reserves for legal matters totaled $1 million as of both September 30, 2019 and December 31, 2018 . Reserves for General and Professional Liability Claims As a general matter, providers of clinical testing services may be subject to lawsuits alleging negligence or other similar legal claims. These suits could involve claims for substantial damages. Any professional liability litigation could also have an adverse impact on the Company's client base and reputation. The Company maintains various liability insurance coverages for, among other things, claims that could result from providing, or failing to provide, clinical testing services, including inaccurate testing results, and other exposures. The Company's insurance coverage limits its maximum exposure on individual claims; however, the Company is essentially self-insured for a significant portion of these claims. Reserves for such matters, including those associated with both asserted and incurred but not reported claims, are established on an undiscounted basis by considering actuarially determined losses based upon the Company's historical and projected loss experience. Such reserves totaled $132 million and $125 million as of September 30, 2019 and December 31, 2018

BUSINESS SEGMENT INFORMATION

BUSINESS SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2019
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 and ACOs. The Company is the world's leading provider of diagnostic information services, which includes providing information and insights based on the 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 2019 and 2018 . 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, 2019 , 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, 2019 and 2018 . 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 consolidated financial statements contained in the Company’s 2018 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, 2019 2018 2019 2018 Net revenues: DIS business $ 1,877 $ 1,810 $ 5,561 $ 5,448 All other operating segments 79 79 239 244 Total net revenues $ 1,956 $ 1,889 $ 5,800 $ 5,692 Operating earnings (loss): DIS business $ 345 $ 333 $ 963 $ 982 All other operating segments 10 11 31 33 General corporate activities (42 ) (40 ) (126 ) (134 ) Total operating income 313 304 868 881 Non-operating expenses, net (43 ) (38 ) (120 ) (122 ) Income from continuing operations before income taxes and equity in earnings of equity method investees 270 266 748 759 Income tax expense (62 ) (48 ) (175 ) (142 ) Equity in earnings of equity method investees, net of taxes 18 9 48 32 Income from continuing operations 226 227 621 649 Income from discontinued operations, net of taxes — — 20 — Net income 226 227 641 649 Less: Net income attributable to noncontrolling interests 11 14 36 40 Net income attributable to Quest Diagnostics $ 215 $ 213 $ 605 $ 609

RELATED PARTIES

RELATED PARTIES	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTIES The Company's equity method investees primarily consist of its clinical trials central laboratory services joint venture and its diagnostic information services joint ventures, which are accounted for under the equity method of accounting. During the three months ended September 30, 2019 and 2018 , the Company recognized net revenues of $8 million and $9 million , respectively, associated with diagnostic information services provided to its equity method investees. During the nine months ended September 30, 2019 and 2018 , the Company recognized net revenues of $26 million and $27 million , respectively, associated with such services. As of both September 30, 2019 and December 31, 2018 , there was $3 million of accounts receivable from equity method investees related to such services. During the three and nine months ended September 30, 2019 , the Company recognized net revenues of $1 million and $6 million , respectively, associated with diagnostic information services provided to a noncontrolling interest partner in a joint venture. As of September 30, 2019 , there was $2 million of accounts receivable from the noncontrolling interest partner related to such services. During both the three months ended September 30, 2019 and 2018 , the Company recognized income of $4 million associated with the performance of certain corporate services, including transition services, for its equity method investees, classified within selling, general and administrative expenses. During both the nine months ended September 30, 2019 and 2018 , the Company recognized income of $12 million associated with the performance of such services classified within selling, general and administrative expenses. As of September 30, 2019 and December 31, 2018 , there was $1 million and $3 million , respectively, of other receivables from equity method investees included in prepaid expenses and other current assets related to these service agreements and other transition related items. In addition, accounts payable and accrued expenses as of both September 30, 2019 and December 31, 2018 included $1 million due to equity method investees.

REVENUE RECOGNITION

REVENUE RECOGNITION	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGITION 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, 2019 and 2018 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 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, by applying the portfolio approach, in exchange for providing services. These estimates include the impact of contractual allowances, including payer denials and price concessions. The portfolios determined using the portfolio approach consist of the following groups of customers: healthcare insurers, government payers, client payers and patients. 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, 2019 2018 2019 2018 Healthcare insurers: Fee-for-service 32 % 32 % 33 % 32 % Capitated 3 3 3 4 Total healthcare insurers 35 35 36 36 Government payers 15 16 15 16 Client payers 33 32 32 31 Patients 13 13 13 13 Total DIS 96 96 96 96 DS 4 4 4 4 Net revenues 100 % 100 % 100 % 100 %

TAXES ON INCOME

TAXES ON INCOME	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
TAXES ON INCOME	TAXES ON INCOME For the three months ended September 30, 2019 and 2018 , the effective income tax rate was 22.9% and 18.1% , respectively. During the three months ended September 30, 2019 , the Company recognized a $6 million income tax benefit due to the release of a valuation allowance associated with net operating loss carryforwards. During the three months ended September 30, 2018, the Company recognized a $13 million income tax benefit due to the release of tax reserves associated with the expiration of the statue of limitations for certain income tax returns. In addition, the effective income tax rate for the three months ended September 30, 2019 and 2018 benefited from $3 million and $4 million , respectively, of excess tax benefits associated with stock-based compensation arrangements. For the nine months ended September 30, 2019 and 2018 , the effective income tax rate was 23.4% and 18.8% , respectively. During the nine months ended September 30, 2019 , the Company recognized a $10 million income tax benefit due to the release of valuation allowances associated with net operating loss carryforwards. During the nine months ended September 30, 2018, the Company recognized a $15 million income tax benefit associated with a change in a tax return accounting method that enabled the Company to accelerate the deduction of certain expenses on its 2017 tax return at the federal corporate statutory tax rate in effect during 2017, and a $13 million income tax benefit due to the release of tax reserves associated with the expiration of the statue of limitations for certain income tax returns. In addition, the effective income tax rate for the nine months ended September 30, 2019 and 2018 benefited from $11 million and $17 million , respectively, of excess tax benefits associated with stock-based compensation arrangements.

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	DISCONTINUED OPERATIONS During the third quarter of 2006, the Company completed the wind down of Nichols Institute Diagnostics ("NID"), a test kit manufacturing subsidiary, which was reported as a discontinued operation for the nine months ended September 30, 2019 and 2018 . Discontinued operations, net of taxes, for the nine months ended September 30, 2019 includes discrete tax benefits of $20 million associated with the favorable resolution of certain tax contingencies related to NID. In addition, net cash provided by operating activities in the consolidated statement of cash flows for the nine months ended September 30, 2019 included a $28 million refund from the taxing authorities related to discontinued operations.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2019
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 2018 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited consolidated financial statements as of December 31, 2018 , 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, 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, 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. 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 Pronouncements	Adoption of New Accounting Standards On January 1, 2019, the Company adopted a new accounting standard issued by the Financial Accounting Standards Board ("FASB") on accounting for leases using the modified retrospective method. This new accounting standard requires a lessee to recognize an asset and liability for most leases on its balance sheet. The Company elected the optional transition method that allowed for a cumulative-effect adjustment to the opening balance of retained earnings recorded on January 1, 2019 and did not restate previously reported results in the comparative periods. The Company also elected the package of practical expedients, which among other things, allowed it to carry forward its historical lease classification. As a result of adoption of the new standard, the Company recorded operating lease assets and lease liabilities of approximately $500 million and $550 million , respectively as of January 1, 2019. The operating lease liability was determined based on the present value of the remaining minimum rental payments and the operating lease asset was determined based on the value of the lease liability, adjusted for the deferred rent balances of approximately $50 million , which were previously included in accounts payable and accrued expenses as well as other liabilities. Accounting for the Company's finance leases remains substantially unchanged. The adoption of the new standard did not materially impact the Company's consolidated results of operations or cash flows. In addition, the adoption of this new accounting standard resulted in increased qualitative and quantitative disclosures regarding the amount, timing, and uncertainty of cash flows arising from leases. For further details, see Note 9. On January 1, 2019, the Company adopted a new accounting standard issued by the FASB that includes the overnight index swap rate based on the Secured Overnight Financing Rate as an additional benchmark interest rate for hedge accounting purposes. Adoption of this new accounting standard applies prospectively to new or redesignated hedges entered into after the adoption date and, therefore, did not have an impact on the Company's existing interest rate swap agreements. New Accounting Standards To Be Adopted In August 2018, the FASB issued an Accounting Standard Update (“ASU”) that aligns the requirements for deferring implementation costs incurred in a cloud computing arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This ASU is effective for the Company in the first quarter of 2020 with early adoption permitted and can be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company is currently assessing the impact of the adoption of this ASU on the Company’s results of operations, financial position and 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, treasury 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 entered into interest rate swaps. 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, 2019
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: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Amounts attributable to Quest Diagnostics’ common stockholders: Income from continuing operations $ 215 $ 213 $ 585 $ 609 Income from discontinued operations, net of taxes — — 20 — Net income attributable to Quest Diagnostics’ common stockholders $ 215 $ 213 $ 605 $ 609 Income from continuing operations $ 215 $ 213 $ 585 $ 609 Less: Earnings allocated to participating securities 1 1 2 2 Earnings available to Quest Diagnostics’ common stockholders – basic and diluted $ 214 $ 212 $ 583 $ 607 Weighted average common shares outstanding – basic 135 136 135 136 Effect of dilutive securities: Stock options and performance share units 2 3 1 3 Weighted average common shares outstanding – diluted 137 139 136 139 Earnings per share attributable to Quest Diagnostics’ common stockholders - basic: Income from continuing operations $ 1.59 $ 1.56 $ 4.33 $ 4.46 Income from discontinued operations — — 0.15 — Net income $ 1.59 $ 1.56 $ 4.48 $ 4.46 Earnings per share attributable to Quest Diagnostics’ common stockholders – diluted: Income from continuing operations $ 1.56 $ 1.53 $ 4.27 $ 4.37 Income from discontinued operations — — 0.15 — Net income $ 1.56 $ 1.53 $ 4.42 $ 4.37
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, 2019 2018 2019 2018 Stock options 2 2 3 2

RESTRUCTURING ACTIVITIES (Table

RESTRUCTURING ACTIVITIES (Tables)	9 Months Ended
	Sep. 30, 2019
Restructuring and Related Activities [Abstract]
Schedule of Pre-Tax Restructuring and Integration Charges	The following table provides a summary of the Company's pre-tax restructuring charges for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Employee separation costs $ — $ 4 $ (3 ) $ 19 Facility-related costs — — — 4 Total restructuring charges $ — $ 4 $ (3 ) $ 23

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 Total Level 1 Level 2 Level 3 Assets: Trading securities $ 55 $ 55 $ — $ — Cash surrender value of life insurance policies 41 — 41 — Available-for-sale debt securities 12 — — 12 Forward-starting interest rate swaps 2 — 2 — Total $ 110 $ 55 $ 43 $ 12 Liabilities: Deferred compensation liabilities $ 104 $ — $ 104 $ — Fixed-to-variable interest rate swaps 17 — 17 — Contingent consideration 7 — — 7 Total $ 128 $ — $ 121 $ 7 Redeemable noncontrolling interest $ 76 $ — $ — $ 76 Basis of Fair Value Measurements December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Trading securities $ 53 $ 53 $ — $ — Cash surrender value of life insurance policies 34 — 34 — Total $ 87 $ 53 $ 34 $ — Liabilities: Deferred compensation liabilities $ 96 $ — $ 96 $ — Fixed-to-variable interest rate swaps 93 — 93 — Contingent consideration 14 — — 14 Total $ 203 $ — $ 189 $ 14 Redeemable noncontrolling interest $ 77 $ — $ — $ 77 In connection with previous business acquisitions, the Company has contingent consideration obligations that are to be paid based on the achievement of certain testing volume or revenue benchmarks. These contingent consideration liabilities are measured at fair value using an option-pricing method and are classified within Level 3 of the fair value hierarchy as the fair value is determined based on significant inputs that are not observable. Significant inputs include management’s estimate of volume or revenue and other market inputs including comparable company revenue volatility and a discount rate. A summary of the significant inputs is as follows: Business Acquisition Fair Value of Contingent Consideration Benchmark Comparable Company Revenue Volatility Discount rate Maximum Contingent Consideration Payment Certain assets of the clinical and anatomic pathology laboratory business of Shiel Holdings, LLC in December 2017 $ 7 Volume 6.9% 4.5% $ 15 ReproSource, Inc. in September 2018 $ — Revenue 8.5% 6.5% $ 10 Certain assets of the clinical laboratory services business of Boyce & Bynum in February 2019 $ — Volume 8.0% 7.2% $ 25
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table provides a reconciliation of the beginning and ending balances of liabilities using significant unobservable inputs (Level 3): Contingent Consideration Balance, December 31, 2018 $ 14 Purchases, additions and issuances 6 Settlements (1 ) Total gains/losses included in earnings - realized/unrealized (12 ) Balance, September 30, 2019 $ 7

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Goodwill, Net	The changes in goodwill for the nine months ended September 30, 2019 and for the year ended December 31, 2018 were as follows: September 30, December 31, Balance, beginning of period $ 6,563 $ 6,335 Goodwill acquired during the period 42 228 Adjustments to goodwill 12 — Balance, end of period $ 6,617 $ 6,563
Intangible Assets Excluding Goodwill	Intangible assets at September 30, 2019 and December 31, 2018 consisted of the following: Weighted Average Amortization Period (in years) September 30, 2019 December 31, 2018 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Amortizing intangible assets: Customer-related 18 $ 1,359 $ (536 ) $ 823 $ 1,355 $ (478 ) $ 877 Non-compete agreements 9 3 (2 ) 1 3 (2 ) 1 Technology 17 104 (54 ) 50 104 (50 ) 54 Other 9 110 (82 ) 28 114 (75 ) 39 Total 17 1,576 (674 ) 902 1,576 (605 ) 971 Intangible assets not subject to amortization: Trade names 235 — 235 235 — 235 Other 1 — 1 1 — 1 Total intangible assets $ 1,812 $ (674 ) $ 1,138 $ 1,812 $ (605 ) $ 1,207
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, 2019 is as follows: Year Ending December 31, Remainder of 2019 $ 24 2020 96 2021 89 2022 86 2023 85 2024 81 Thereafter 441 Total $ 902

DEBT (Tables)

DEBT (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Instruments [Abstract]
Long-term Debt	Long-term debt (including finance lease obligations) as of September 30, 2019 and December 31, 2018 consisted of the following: September 30, 2019 December 31, Secured Receivables Credit Facility (3.39% at December 31, 2018) $ — $ 160 2.70% Senior Notes due April 2019 — 300 4.75% Senior Notes due January 2020 501 507 2.50% Senior Notes due March 2020 300 300 4.70% Senior Notes due April 2021 554 557 4.25% Senior Notes due April 2024 310 299 3.50% Senior Notes due March 2025 600 562 3.45% Senior Notes due June 2026 494 469 4.20% Senior Notes due June 2029 499 — 6.95% Senior Notes due July 2037 175 175 5.75% Senior Notes due January 2040 244 244 4.70% Senior Notes due March 2045 300 300 Other 35 37 Debt issuance costs (19 ) (17 ) Total long-term debt 3,993 3,893 Less: Current portion of long-term debt 805 464 Total long-term debt, net of current portion $ 3,188 $ 3,429
Schedule of Maturities of Long-term Debt	As of September 30, 2019 , long-term debt matures as follows: Year Ending December 31, Remainder of 2019 $ 1 2020 803 2021 553 2022 3 2023 1 Thereafter 2,649 Total maturities of long-term debt 4,010 Unamortized discount (9 ) Debt issuance costs (19 ) Fair value basis adjustments attributable to hedged debt 11 Total long-term debt 3,993 Current portion of long-term debt 805 Total long-term debt, net of current portion $ 3,188

LEASES (Tables)

LEASES (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedule Of Lease By Asset Type	Certain of the Company's lease agreements include rental payments adjusted periodically for inflation or a market rate which are included in the lease liabilities. Leases Balance Sheet Classification September 30, 2019 Assets Operating Operating lease right-of-use assets $ 508 Finance Property, plant and equipment, net (a) 37 Total lease assets $ 545 Liabilities Current: Operating Current portion of long-term operating lease liabilities $ 147 Finance Current portion of long-term debt 3 Non-current: Operating Long-term operating lease liabilities 405 Finance Long-term debt 31 Total lease liabilities $ 586 (a) Finance lease assets were recorded net of accumulated amortization of $23 million as of September 30, 2019 .
Lease, Cost	Components of lease cost for the three and nine months ended September 30, 2019 were as follows: Lease cost Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Operating lease cost (a) $ 75 $ 221 Finance lease cost: Amortization of leased assets 1 5 Interest on lease liabilities — 2 Net lease cost $ 76 $ 228 (a) Includes short-term leases and variable lease costs (primarily maintenance fees and utilities related to real estate leases and certain equipment-related and vehicle-related costs) of $32 million and $90 million for the three and nine months ended September 30, 2019 , respectively. Rental expense for real estate, laboratory equipment and vehicles under operating leases amounted to $55 million and $167 million for the three and nine months ended September 30, 2018 , respectively.
Operating Lease, Liability, Maturity	The maturity of the Company's lease liabilities as of September 30, 2019 is as follows: Maturity of lease liabilities Operating leases Finance leases Total Remainder of 2019 $ 32 $ 1 $ 33 2020 155 6 161 2021 118 5 123 2022 93 5 98 2023 74 3 77 Thereafter 138 35 173 Total lease payments 610 55 665 Less: Interest (a) 58 21 79 Present value of lease liabilities $ 552 $ 34 $ 586 (a) Primarily calculated using the Company's incremental borrowing rate.
Finance Lease, Liability, Maturity	The maturity of the Company's lease liabilities as of September 30, 2019 is as follows: Maturity of lease liabilities Operating leases Finance leases Total Remainder of 2019 $ 32 $ 1 $ 33 2020 155 6 161 2021 118 5 123 2022 93 5 98 2023 74 3 77 Thereafter 138 35 173 Total lease payments 610 55 665 Less: Interest (a) 58 21 79 Present value of lease liabilities $ 552 $ 34 $ 586 (a) Primarily calculated using the Company's incremental borrowing rate.
Schedule of Future Minimum Rental Payments for Operating Leases	Minimum rental commitments under noncancelable operating leases, primarily real estate, in effect as of December 31, 2018 are as follows: Year Ending December 31, 2019 $ 181 2020 143 2021 106 2022 79 2023 60 Thereafter 122 Minimum lease payments $ 691
Schedule of Lease Term and Discount Rate	Lease term and discount rate as of September 30, 2019 were as follows: Lease term and discount rate Weighted-average remaining lease term (years): Operating leases 5 Finance leases 12 Weighted-average discount rate: Operating leases 3.3 % Finance leases 8.7 %

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	A summary of the notional amounts of these interest rate swaps as of September 30, 2019 and December 31, 2018 was as follows: Notional Amount Debt Instrument September 30, 2019 December 31, 2018 4.25% Senior Notes due April 2024 $ 250 $ 250 3.50% Senior Notes due March 2025 600 600 3.45% Senior Notes due June 2026 350 350 $ 1,200 $ 1,200
Schedule of Debt Instrument Fair Value Basis Adjustment Attributable to Hedged Debt	As of September 30, 2019 and December 31, 2018 , the following amounts were recorded on the consolidated balance sheet related to cumulative basis adjustments for fair value hedges included in the carrying amount of long-term debt: Carrying Amount of Hedged Long-Term Debt Hedge Accounting Basis Adjustment (a) Carrying Amount of Hedged Long-Term Debt Hedge Accounting Basis Adjustment (a) Balance Sheet Classification September 30, 2019 September 30, 2019 December 31, 2018 December 31, 2018 Long-term debt $ 1,198 $ 11 $ 1,125 $ (53 ) (a) The balance includes $28 million and $40 million of remaining unamortized hedging adjustment on a discontinued relationship as of September 30, 2019 and December 31, 2018 , respectively.
Schedule of Fair Value Hedge Accounting on the Statement of Operations	The following table presents the effect of fair value hedge accounting on the statement of operations for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 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 $ 1 $ 3 $ 13 $ 2 Gain (loss) on fair value hedging relationships: Hedged items (Long-term debt) $ (20 ) $ 10 $ (76 ) $ 42 Derivatives designated as hedging instruments $ 20 $ (10 ) $ 76 $ (42 )
Schedule of Derivative Instruments at Fair Value	A summary of the fair values of derivative instruments in the consolidated balance sheets was as follows: September 30, 2019 December 31, 2018 Derivatives Designated as Hedging Instruments Balance Sheet Classification Fair Value Balance Sheet Classification Fair Value Forward-starting interest rate swaps Prepaid expenses and other current assets $ 2 Prepaid expenses and other current assets $ — Fixed-to-variable interest rate swaps Other liabilities $ 17 Other liabilities $ 93

SUPPLEMENTAL CASH FLOW & OTHE_2

SUPPLEMENTAL CASH FLOW & OTHER DATA (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and 2018 was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Depreciation expense $ 59 $ 55 $ 175 $ 162 Amortization expense 23 22 72 66 Depreciation and amortization expense $ 82 $ 77 $ 247 $ 228 Interest expense $ (45 ) $ (42 ) $ (136 ) $ (126 ) Interest income 1 1 3 2 Interest expense, net $ (44 ) $ (41 ) $ (133 ) $ (124 ) Interest paid $ 58 $ 28 $ 149 $ 114 Income taxes paid $ 65 $ 29 $ 148 $ 70 Accounts payable associated with capital expenditures $ 24 $ 13 $ 24 $ 13 Dividends payable $ 72 $ 68 $ 72 $ 68 Businesses acquired: Fair value of assets acquired $ — $ 59 $ 61 $ 242 Fair value of liabilities assumed — — — 1 Fair value of net assets acquired — 59 61 241 Merger consideration paid (payable), net — (5 ) (5 ) (17 ) Cash paid for business acquisitions — 54 56 224 Less: Cash acquired — — — 5 Business acquisitions, net of cash acquired $ — $ 54 $ 56 $ 219 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Leases: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 45 $ 135 Operating cash flows from finance leases $ — $ 2 Financing cash flows from finance leases $ 1 $ 3 Leased assets obtained in exchange for new operating lease liabilities $ 38 $ 116 Leased assets obtained in exchange for new finance lease liabilities (a) $ 1 $ — $ 1 $ 1 (a) For the three and nine months ended September 30, 2018, leased assets obtained in exchange for new finance lease liabilities reflects information prior to the adoption of the new accounting standard related to accounting for leases. See Note 2 for further details on the adoption of the new accounting standard.

BUSINESS SEGMENT INFORMATION (T

BUSINESS SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and 2018 . 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 consolidated financial statements contained in the Company’s 2018 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, 2019 2018 2019 2018 Net revenues: DIS business $ 1,877 $ 1,810 $ 5,561 $ 5,448 All other operating segments 79 79 239 244 Total net revenues $ 1,956 $ 1,889 $ 5,800 $ 5,692 Operating earnings (loss): DIS business $ 345 $ 333 $ 963 $ 982 All other operating segments 10 11 31 33 General corporate activities (42 ) (40 ) (126 ) (134 ) Total operating income 313 304 868 881 Non-operating expenses, net (43 ) (38 ) (120 ) (122 ) Income from continuing operations before income taxes and equity in earnings of equity method investees 270 266 748 759 Income tax expense (62 ) (48 ) (175 ) (142 ) Equity in earnings of equity method investees, net of taxes 18 9 48 32 Income from continuing operations 226 227 621 649 Income from discontinued operations, net of taxes — — 20 — Net income 226 227 641 649 Less: Net income attributable to noncontrolling interests 11 14 36 40 Net income attributable to Quest Diagnostics $ 215 $ 213 $ 605 $ 609

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 2019 2018 Healthcare insurers: Fee-for-service 32 % 32 % 33 % 32 % Capitated 3 3 3 4 Total healthcare insurers 35 35 36 36 Government payers 15 16 15 16 Client payers 33 32 32 31 Patients 13 13 13 13 Total DIS 96 96 96 96 DS 4 4 4 4 Net revenues 100 % 100 % 100 % 100 %

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Operating lease, right-of-use asset	$ 508	$ 500	$ 0
Present value of lease liabilities	$ 552	550
Deferred rent		$ 50

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Income from continuing operations	$ 215	$ 213	$ 585	$ 609
Income from discontinued operations, net of taxes	0	0	20	0
Net income attributable to Quest Diagnostics	215	213	605	609
Less: Earnings allocated to participating securities	1	1	2	2
Earnings available to Quest Diagnostics' common stockholders - basic and diluted	$ 214	$ 212	$ 583	$ 607
Weighted average common shares outstanding - basic	135	136	135	136
Stock options and performance share units	2	3	1	3
Weighted average common shares outstanding - diluted	137	139	136	139
Income from continuing operations (in dollars per share)	$ 1.59	$ 1.56	$ 4.33	$ 4.46
Income from discontinued operations (in dollars per share)	0	0	0.15	0
Net income (in dollars per share)	1.59	1.56	4.48	4.46
Income from continuing operations (in dollars per share)	1.56	1.53	4.27	4.37
Income from discontinued operations (in dollars per share)	0	0	0.15	0
Net income (in dollars per share)	$ 1.56	$ 1.53	$ 4.42	$ 4.37
Stock options and performance share units not included due to their antidilutive effect	2	2	3	2

RESTRUCTURING ACTIVITIES (Pre-T

RESTRUCTURING ACTIVITIES (Pre-Tax Restructuring and Integration Charges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Employee separation costs	$ 0	$ 4	$ (3)	$ 19
Facility-related costs	0	0	0	4
Total restructuring charges	$ 0	$ 4	$ (3)	$ 23

RESTRUCTURING ACTIVITIES (Narra

RESTRUCTURING ACTIVITIES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 0	$ 4	$ (3)	$ 23
Accounts Payable and Accrued Liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 11		11		$ 38
Cost of services
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		2	(1)	9
Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		$ 2	$ (2)	$ 14

BUSINESS ACQUISITIONS (Details)

BUSINESS ACQUISITIONS (Details) - USD ($)	Feb. 11, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Cash paid for business acquisitions			$ 0	$ 54,000,000	$ 56,000,000	$ 224,000,000
Goodwill		$ 6,617,000,000	6,617,000,000		$ 6,617,000,000		$ 6,563,000,000	$ 6,335,000,000
Customer Relationships
Business Acquisition [Line Items]
Intangible assets, useful life					18 years
Boyce & Bynum
Business Acquisition [Line Items]
Consideration	$ 61,000,000
Cash paid for business acquisitions	55,000,000
Goodwill	41,000,000
Goodwill, expected tax deductible amount	35,000,000
Boyce & Bynum | Customer Relationships
Business Acquisition [Line Items]
Intangible assets	$ 20,000,000
Intangible assets, useful life	15 years
Boyce & Bynum | Other Operating Income
Business Acquisition [Line Items]
Gain due to reduction in liability			6,000,000
Boyce & Bynum | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Contingent consideration	$ 6,000,000	0	$ 0		$ 0
Oxford Immunotec, Inc.
Business Acquisition [Line Items]
Adjustment, increase to goodwill		13,000,000
Adjustment, decrease to intangible assets		11,000,000
Adjustment, other assets and liabilities		$ 2,000,000

FAIR VALUE MEASUREMENTS (Recogn

FAIR VALUE MEASUREMENTS (Recognized Assets and Liabilities at Fair Value) (Details) - Recurring Basis - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 55	$ 53
Cash surrender value of life insurance policies	41	34
Available-for-sale debt securities	12
Forward-starting interest rate swaps	2
Total assets	110	87
Deferred compensation liabilities	104	96
Fixed-to-variable interest rate swaps	17	93
Contingent consideration	7	14
Total liabilities	128	203
Redeemable noncontrolling interest	76	77
Quoted Prices in Active Markets for Identical Assets / Liabilities, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	55	53
Cash surrender value of life insurance policies	0	0
Available-for-sale debt securities	0
Total assets	55	53
Deferred compensation liabilities	0	0
Fixed-to-variable interest rate swaps	0	0
Contingent consideration	0	0
Total 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	41	34
Available-for-sale debt securities	0
Forward-starting interest rate swaps	2
Total assets	43	34
Deferred compensation liabilities	104	96
Fixed-to-variable interest rate swaps	17	93
Contingent consideration	0	0
Total liabilities	121	189
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
Available-for-sale debt securities	12
Forward-starting interest rate swaps	0
Total assets	12	0
Deferred compensation liabilities	0	0
Fixed-to-variable interest rate swaps	0	0
Contingent consideration	7	14
Total liabilities	7	14
Redeemable noncontrolling interest	$ 76	$ 77

FAIR VALUE MEASUREMENTS (Busine

FAIR VALUE MEASUREMENTS (Business Acquisition) (Details)	Sep. 30, 2019USD ($)	Feb. 11, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Shiel Holdings LLC (Shiel)
Business Acquisition [Line Items]
Maximum Contingent Consideration Payment				$ 15,000,000
Shiel Holdings LLC (Shiel) | Comparable Company Revenue Volatility
Business Acquisition [Line Items]
Measurement input				0.069
Shiel Holdings LLC (Shiel) | Discount rate
Business Acquisition [Line Items]
Measurement input				0.045
Shiel Holdings LLC (Shiel) | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Fair Value of Contingent Consideration	$ 7,000,000
ReproSource, Inc. in September 2018
Business Acquisition [Line Items]
Maximum Contingent Consideration Payment			$ 10,000,000
ReproSource, Inc. in September 2018 | Comparable Company Revenue Volatility
Business Acquisition [Line Items]
Measurement input			0.085
ReproSource, Inc. in September 2018 | Discount rate
Business Acquisition [Line Items]
Measurement input			0.065
ReproSource, Inc. in September 2018 | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Fair Value of Contingent Consideration	0
Boyce & Bynum
Business Acquisition [Line Items]
Maximum Contingent Consideration Payment		$ 25,000,000
Boyce & Bynum | Comparable Company Revenue Volatility
Business Acquisition [Line Items]
Measurement input		0.080
Boyce & Bynum | Discount rate
Business Acquisition [Line Items]
Measurement input		0.072
Boyce & Bynum | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Fair Value of Contingent Consideration	$ 0	$ 6,000,000

FAIR VALUE MEASUREMENTS (Reconc

FAIR VALUE MEASUREMENTS (Reconciliation of Beginning and Ending Balances of Assets and Liabilities Unobservable Inputs) (Details) - Significant Unobservable Inputs, Level 3 - Contingent Consideration $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, December 31, 2018	$ 14
Purchases, additions and issuances	6
Settlements	(1)
Total gains/losses included in earnings - realized/unrealized	12
Balance, September 30, 2019	$ 7

FAIR VALUE MEASUREMENTS (Narrat

FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Billions	Sep. 30, 2019	Dec. 31, 2018	Jul. 01, 2015
Fair Value Disclosures [Abstract]
Fair value of debt	$ 4.3	$ 4
UMass Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [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, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, Balance at beginning of period	$ 6,563	$ 6,335
Goodwill acquired during the period	42	228
Adjustments to goodwill	12	0
Goodwill, Balance at end of period	$ 6,617	$ 6,563

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS (Schedules) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, Cost	$ 1,812		$ 1,812		$ 1,812
Intangible assets, Accumulated Amortization	(674)		(674)		(605)
Total intangible assets, Net	1,138		1,138		1,207
Amortization expense	23	$ 22	72	$ 66
Remainder of 2019	24		24
Future Amortization Expense, 2020	96		96
Future Amortization Expense, 2021	89		89
Future Amortization Expense, 2022	86		86
Future Amortization Expense, 2023	85		85
Future Amortization Expense, 2024	81		81
Future Amortization Expense, Thereafter	441		441
Future Amortization Expense, Total	902		902
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			18 years
Intangible assets, Cost	1,359		$ 1,359		1,355
Intangible assets, Accumulated Amortization	(536)		(536)		(478)
Total intangible assets, Net	823		$ 823		877
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			17 years
Intangible assets, Cost	104		$ 104		104
Intangible assets, Accumulated Amortization	(54)		(54)		(50)
Total intangible assets, Net	50		$ 50		54
Other
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			9 years
Intangible assets, Cost	110		$ 110		114
Intangible assets, Accumulated Amortization	(82)		(82)		(75)
Total intangible assets, Net	28		$ 28		39
Total Amortizing Intangible Assets
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted Average Amortization Period			17 years
Intangible assets, Cost	1,576		$ 1,576		1,576
Intangible assets, Accumulated Amortization	(674)		(674)		(605)
Total intangible assets, Net	$ 902		$ 902		$ 971

DEBT (Long-Term Debt) (Details)

DEBT (Long-Term Debt) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Mar. 31, 2019
Debt Instrument [Line Items]
Total long-term debt	$ 3,993	$ 3,893
Debt issuance costs	(19)	(17)
Less: Current portion of long-term debt	805	464
Total long-term debt, net of current portion	3,188	3,429
Secured Receivables Credit Facility
Debt Instrument [Line Items]
Total long-term debt	0	$ 160
Credit facility borrowing rate		3.39%
2.70% Senior Notes due April 2019
Debt Instrument [Line Items]
Total long-term debt	0	$ 300
Debt instrument, interest rate		2.70%
Debt instrument, maturity date		Apr. 1, 2019
4.75% Senior Notes due January 2020
Debt Instrument [Line Items]
Total long-term debt	$ 501	$ 507
Debt instrument, interest rate	4.75%
Debt instrument, maturity date	Jan. 30, 2020
2.50% Senior Notes due March 2020
Debt Instrument [Line Items]
Total long-term debt	$ 300	300
Debt instrument, interest rate	2.50%
Debt instrument, maturity date	Mar. 30, 2020
4.70% Senior Notes due April 2021
Debt Instrument [Line Items]
Total long-term debt	$ 554	557
Debt instrument, interest rate	4.70%
Debt instrument, maturity date	Apr. 1, 2021
4.25% Senior Notes due April 2024
Debt Instrument [Line Items]
Total long-term debt	$ 310	299
Debt instrument, interest rate	4.25%
Debt instrument, maturity date	Apr. 1, 2024
3.50% Senior Notes due March 2025
Debt Instrument [Line Items]
Total long-term debt	$ 600	562
Debt instrument, interest rate	3.50%
Debt instrument, maturity date	Mar. 30, 2025
3.45% Senior Notes due June 2026
Debt Instrument [Line Items]
Total long-term debt	$ 494	469
Debt instrument, interest rate	3.45%
Debt instrument, maturity date	Jun. 30, 2026
4.20% Senior Notes due June 2029
Debt Instrument [Line Items]
Total long-term debt	$ 499	0
Debt instrument, interest rate	4.20%		4.20%
Debt instrument, maturity date	Jun. 30, 2029
6.95% Senior Notes due July 2037
Debt Instrument [Line Items]
Total long-term debt	$ 175	175
Debt instrument, interest rate	6.95%
Debt instrument, maturity date	Jul. 1, 2037
5.75% Senior Notes due January 2040
Debt Instrument [Line Items]
Total long-term debt	$ 244	244
Debt instrument, interest rate	5.75%
Debt instrument, maturity date	Jan. 30, 2040
4.70% Senior Notes due March 2045
Debt Instrument [Line Items]
Total long-term debt	$ 300	300
Debt instrument, interest rate	4.70%
Debt instrument, maturity date	Mar. 30, 2045
Other
Debt Instrument [Line Items]
Other	$ 35	$ 37

DEBT (Narrative) (Details)

DEBT (Narrative) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Debt Instrument [Line Items]
Unamortized discount	$ 9,000,000
Proceeds from borrowings	1,484,000,000	$ 1,630,000,000
Repayments of debt	1,448,000,000	$ 1,665,000,000
Secured Receivables Credit Facility
Debt Instrument [Line Items]
Proceeds from borrowings	985,000,000
Repayments of debt	$ 1,145,000,000
4.20% Senior Notes due June 2029
Debt Instrument [Line Items]
Face amount			$ 500,000,000
Debt instrument, interest rate	4.20%		4.20%
Unamortized discount			$ 1,000,000
Debt issuance costs			$ 5,000,000

DEBT (Maturities of Long-Term D

DEBT (Maturities of Long-Term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Instruments [Abstract]
Remainder of 2019	$ 1
2020	803
2021	553
2022	3
2023	1
Thereafter	2,649
Total maturities of long-term debt	4,010
Unamortized discount	(9)
Debt issuance costs	(19)	$ (17)
Fair value basis adjustments attributable to hedged debt	11
Total long-term debt	3,993	3,893
Current portion of long-term debt	805	464
Total long-term debt, net of current portion	$ 3,188	$ 3,429

LEASES (Narrative) (Details)

LEASES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Leases [Abstract]
Operating leases, rent expense	$ 55		$ 167
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term		15 years
Renewal term		15 years

LEASES LEASES (Liabilities) (De

LEASES LEASES (Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets	$ 508	$ 500	$ 0
Finance lease assets	37
Total lease assets	545
Current operating lease liabilities	147		0
Current finance lease liabilities	3
Noncurrent operating lease liabilities	405		$ 0
Noncurrent finance lease liabilities	31
Total lease liabilities	586
Amortization of leased assets	$ 23

LEASES (Costs) (Details)

LEASES (Costs) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 75	$ 221
Finance lease cost:
Amortization of leased assets	1	5
Interest on lease liabilities	0	2
Net lease cost	76	228
Short-term leases and variable lease costs	$ 32	$ 90

LEASES (Maturity) (Details)

LEASES (Maturity) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Operating leases
Remainder of 2019	$ 32
2020	155
2021	118
2022	93
2023	74
Thereafter	138
Total lease payments	610
Less: Interest	58
Present value of lease liabilities	552	$ 550
Finance leases
Remainder of 2019	1
2020	6
2021	5
2022	5
2023	3
Thereafter	35
Total lease payments	55
Less: Interest	21
Present value of lease liabilities	34
Total
Remainder of 2019	33
2020	161
2021	123
2022	98
2023	77
Thereafter	173
Total lease payments	665
Less: Interest	79
Present value of lease liabilities	$ 586

LEASES (Rent Payments) (Details

LEASES (Rent Payments) (Details) $ in Millions	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 181
2020	143
2021	106
2022	79
2023	60
Thereafter	122
Minimum lease payments	$ 691

LEASES (Term and Rate) (Details

LEASES (Term and Rate) (Details)	Sep. 30, 2019
Leases [Abstract]
Weighted-average remaining lease term, Operating leases	5 years
Weighted-average remaining lease term,Finance leases	12 years
Weighted-average discount rate, Operating leases	3.30%
Weighted-average discount rate, Finance leases	8.70%

FINANCIAL INSTRUMENTS (Narrativ

FINANCIAL INSTRUMENTS (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Feb. 28, 2019	Dec. 31, 2018
Derivative [Line Items]
Accumulated other comprehensive loss			$ (55)		$ (59)
Cash Flow Hedging
Derivative [Line Items]
Accumulated other comprehensive loss			(7)		$ (9)
Cash Flow Hedging | Scenario, Forecast
Derivative [Line Items]
Net amount of deferred gains and losses on cash flow hedges that is expected to be reclassified within the next 12 months		$ 1
Cash Flow Hedging | Treasury Lock
Derivative [Line Items]
Notional amount				$ 250
Gain (loss) on derivatives	$ (1)
Cash Flow Hedging | Forward-starting Interest Rate Swap Agreements
Derivative [Line Items]
Notional amount			$ 125
Fair Value Hedging | One-Month LIBOR | Minimum
Derivative [Line Items]
Floating rate			2.20%
Fair Value Hedging | One-Month LIBOR | Maximum
Derivative [Line Items]
Floating rate			3.00%

FINANCIAL INSTRUMENTS (Summary

FINANCIAL INSTRUMENTS (Summary of Notional Amounts) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
4.25% Senior Notes due April 2024
Derivative [Line Items]
Debt instrument, interest rate	4.25%
Debt instrument, maturity date	Apr. 1, 2024
3.50% Senior Notes due March 2025
Derivative [Line Items]
Debt instrument, interest rate	3.50%
Debt instrument, maturity date	Mar. 30, 2025
3.45% Senior Notes due June 2026
Derivative [Line Items]
Debt instrument, interest rate	3.45%
Debt instrument, maturity date	Jun. 30, 2026
Interest Rate Swaps | Fair Value Hedging
Derivative [Line Items]
Notional Amount	$ 1,200	$ 1,200
Interest Rate Swaps | Fair Value Hedging | 4.25% Senior Notes due April 2024
Derivative [Line Items]
Notional Amount	250	250
Interest Rate Swaps | Fair Value Hedging | 3.50% Senior Notes due March 2025
Derivative [Line Items]
Notional Amount	600	600
Interest Rate Swaps | Fair Value Hedging | 3.45% Senior Notes due June 2026
Derivative [Line Items]
Notional Amount	$ 350	$ 350

FINANCIAL INSTRUMENTS (Balance

FINANCIAL INSTRUMENTS (Balance Sheets) (Details) - Long-term Debt - Fair Value Hedging - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Carrying Amount of Hedged Long-Term Debt	$ 1,198	$ 1,125
Fair value basis adjustments attributable to hedged debt	11	(53)
Hedging adjustment on a discontinued relationship	$ 28	$ 40

FINANCIAL INSTRUMENTS (Income S

FINANCIAL INSTRUMENTS (Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
Other income, net	$ 1	$ 3	$ 13	$ 2
Other Nonoperating Income (Expense)
Derivative [Line Items]
Hedged items (Long-term debt)	(20)	10	(76)	42
Other Nonoperating Income (Expense) | Fair Value Hedging
Derivative [Line Items]
Derivatives designated as hedging instruments	$ 20	$ (10)	$ 76	$ (42)

FINANCIAL INSTRUMENTS (Summar_2

FINANCIAL INSTRUMENTS (Summary of Fair Value of Derivatives) (Details) - Derivatives Designated as Hedging Instruments - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Forward starting interest rate swaps | Prepaid expenses and other current assets
Derivative [Line Items]
Derivative Asset	$ 2	$ 0
Fixed-to-variable interest rate swaps | Other liabilities
Derivative [Line Items]
Derivative Liabilities	$ 17	$ 93

STOCKHOLDERS_ EQUITY AND REDE_2

STOCKHOLDERS’ EQUITY AND REDEEMABLE NONCONTROLLING INTEREST (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended							9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Jul. 01, 2015
Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]
Dividends per common share	$ 0.53	$ 0.53	$ 0.53	$ 0.53	$ 0.50	$ 0.50	$ 0.50
Share repurchase authorization remaining available	$ 442							$ 442
Purchases of treasury stock, value	50				$ 100			$ 150	$ 150
Reissuance of shares for employee benefit plan								1.8	1.7
UMass Joint Venture
Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]
Ownership percentage by noncontrolling owners										18.90%
Treasury Stock, at Cost [Member]
Schedule of Stockholders' Equity and Redeemable Noncontrolling Interest [Line Items]
Purchases of treasury stock- shares								1.6	1.4
Purchases of treasury stock, value	$ 50				$ 100			$ 150	$ 150

SUPPLEMENTAL CASH FLOW & OTHE_3

SUPPLEMENTAL CASH FLOW & OTHER DATA (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Depreciation expense	$ 59	$ 55	$ 175	$ 162
Amortization expense	23	22	72	66
Depreciation and amortization expense	82	77	247	228
Interest expense	(45)	(42)	(136)	(126)
Interest income	1	1	3	2
Interest expense, net	(44)	(41)	(133)	(124)
Interest paid	58	28	149	114
Income taxes paid	65	29	148	70
Accounts payable associated with capital expenditures	24	13	24	13
Dividends payable	72	68	72	68
Fair value of assets acquired	0	59	61	242
Fair value of liabilities assumed	0	0	0	1
Fair value of net assets acquired	0	59	61	241
Merger consideration paid (payable), net	0	(5)	(5)	(17)
Cash paid for business acquisitions	0	54	56	224
Less: Cash acquired	0	0	0	5
Business acquisitions, net of cash acquired	0	54	56	219
Leases:
Operating cash flows from operating leases	45		135
Operating cash flows from finance leases	0		2
Financing cash flows from finance leases	1		3
Leased assets obtained in exchange for new operating lease liabilities	38		116
Leased assets obtained in exchange for new finance lease liabilities (a)	$ 1		$ 1
Leased assets obtained in exchange for new finance lease liabilities		$ 0		$ 1

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details)	4 Months Ended
	Sep. 30, 2019USD ($)claim	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Litigation reserves	$ 1,000,000	$ 1,000,000
Self-insurance reserves	132,000,000	$ 125,000,000
Secured Receivables Credit Facility
Debt Instrument [Line Items]
Letters of credit outstanding, amount	$ 71,000,000
AMAC Data Security Incident
Loss Contingencies [Line Items]
Class action lawsuits | claim	39
Letter of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility capacity	$ 150,000,000
Letter of Credit | Secured Receivables Credit Facility
Debt Instrument [Line Items]
Credit facility capacity	$ 100,000,000

BUSINESS SEGMENT INFORMATION (D

BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Percentage of net revenues	100.00%	100.00%	100.00%	100.00%
Total net revenues	$ 1,956	$ 1,889	$ 5,800	$ 5,692
Total operating income	313	304	868	881
Non-operating expenses, net	(43)	(38)	(120)	(122)
Income from continuing operations before income taxes and equity in earnings of equity method investees	270	266	748	759
Income tax expense	(62)	(48)	(175)	(142)
Equity in earnings of equity method investees, net of taxes	18	9	48	32
Income from continuing operations	226	227	621	649
Income from discontinued operations, net of taxes	0	0	20	0
Net income	226	227	641	649
Less: Net income attributable to noncontrolling interests	11	14	36	40
Net income attributable to Quest Diagnostics	$ 215	$ 213	$ 605	$ 609
DIS business
Segment Reporting Information [Line Items]
Percentage of net revenues	96.00%	96.00%	96.00%	96.00%
Total net revenues	$ 1,877	$ 1,810	$ 5,561	$ 5,448
Total operating income	$ 345	$ 333	$ 963	$ 982
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	$ 79	$ 79	$ 239	$ 244
Total operating income	10	11	31	33
General corporate activities
Segment Reporting Information [Line Items]
Total operating income	$ (42)	$ (40)	$ (126)	$ (134)

RELATED PARTIES (Details)

RELATED PARTIES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Equity Method Investee
Related Party Transaction [Line Items]
Revenues	$ 8	$ 9	$ 26	$ 27
Receivables	3		3		$ 3
Accounts payable, related parties	1		1		1
Equity Method Investee | Prepaid expenses and other current assets
Related Party Transaction [Line Items]
Other accounts receivable, related parties	1		1		$ 3
Equity Method Investee | Selling, general and administrative
Related Party Transaction [Line Items]
Income from related party recognized	4	$ 4	12	$ 12
Joint Venture
Related Party Transaction [Line Items]
Revenues	1		6
Receivables	$ 2		$ 2

REVENUE RECOGNITION (Details)

REVENUE RECOGNITION (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Percentage of net revenues	100.00%	100.00%	100.00%	100.00%
DIS business
Segment Reporting Information [Line Items]
Percentage of net revenues	96.00%	96.00%	96.00%	96.00%
DIS business | Healthcare Insurers
Segment Reporting Information [Line Items]
Percentage of net revenues	35.00%	35.00%	36.00%	36.00%
DIS business | Healthcare Insurers | Fee-for-service
Segment Reporting Information [Line Items]
Percentage of net revenues	32.00%	32.00%	33.00%	32.00%
DIS business | Healthcare Insurers | Capitated
Segment Reporting Information [Line Items]
Percentage of net revenues	3.00%	3.00%	3.00%	4.00%
DIS business | Government Payers
Segment Reporting Information [Line Items]
Percentage of net revenues	15.00%	16.00%	15.00%	16.00%
DIS business | Client Payers
Segment Reporting Information [Line Items]
Percentage of net revenues	33.00%	32.00%	32.00%	31.00%
DIS business | Patients
Segment Reporting Information [Line Items]
Percentage of net revenues	13.00%	13.00%	13.00%	13.00%
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	4.00%	4.00%	4.00%	4.00%

TAXES ON INCOME (Details)

TAXES ON INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate	22.90%	18.10%	23.40%	18.80%
Income tax benefit due to the release of a valuation allowance associated with net operating loss carryforwards	$ 6		$ 10
Release of tax reserves associated with expiration of statute of limitation		$ 13		$ 13
Share-based compensation, excess tax benefit, amount	$ 3	$ 4	$ 11	17
Income tax benefit associated with changes in tax return accounting method				$ 15

DISCONTINUED OPERATIONS (Detail

DISCONTINUED OPERATIONS (Details) - NID [Member] $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on settling uncertain tax benefits	$ 20
Refund from taxing authorities related to settlement of the uncertain tax benefits	$ 28

Uncategorized Items - dgx093020

Label	Element	Value
Restricted Cash	us-gaap_RestrictedCash	$ 0
Restricted Cash	us-gaap_RestrictedCash	0
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	20,000,000
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	16,000,000
Additional Paid-in Capital [Member]
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	4,000,000
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	16,000,000
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	$ 20,000,000