BUSINESS ACQUISITIONS - Additional Information (Details) $ in Millions												12 Months Ended
	Dec. 30, 2024 USD ($)	Oct. 13, 2024 USD ($)	Sep. 30, 2024 USD ($)	Sep. 16, 2024 USD ($)	Aug. 23, 2024 USD ($)	Aug. 23, 2024 CAD ($)	Jun. 10, 2024 USD ($)	Feb. 12, 2024 USD ($)	Jun. 20, 2023 USD ($)	Apr. 17, 2023 USD ($)	Feb. 01, 2022 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2024 USD ($)
Business Acquisition [Line Items]
Total consideration												$ 2,200,000,000	$ 699,000,000	$ 162,000,000
Contingent consideration													88,000,000	18,000,000	$ 6,000,000
Business acquisitions, net of cash acquired												2,164,000,000	611,000,000	144,000,000
Goodwill acquired during the year												1,146,000,000	511,000,000	121,000,000
Goodwill deductible for tax purposes												862,000,000	244,000,000	103,000,000
Cash consideration												2,214,000,000	612,000,000	148,000,000
Net revenues												9,872,000,000	9,252,000,000	9,883,000,000
Goodwill												8,856,000,000	7,733,000,000	7,220,000,000
Cash acquired from acquisition												$ 50,000,000	1,000,000	4,000,000
Minimum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life												5 years
Maximum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life												25 years
Customer - related
Business Acquisition [Line Items]
Finite-lived intangibles													63,000,000	$ 45,000,000
Finite-lived intangible asset, useful life												18 years
Trade names
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life												15 years
Non-competition agreements
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life												5 years
Technology-based intangible assets
Business Acquisition [Line Items]
Finite-lived intangibles													$ 145,000,000
Finite-lived intangible asset, useful life												15 years
Current Year Acquisitions, Prepaids in Previous Year
Business Acquisition [Line Items]
Business acquisitions, net of cash acquired												$ (30,000,000)
Current Year Acquisitions, Prepaids in Previous Year
Business Acquisition [Line Items]
Total consideration												30,000,000
Lenco Diagnostics Laboratories, Inc.
Business Acquisition [Line Items]
Cash consideration								$ 111,000,000
PathAI Diagnostics
Business Acquisition [Line Items]
Cash consideration							$ 100,000,000
LifeLabs
Business Acquisition [Line Items]
Cash consideration					$ 1,000,000,000	$ 1,350
Net revenues												241,000,000
Goodwill												303,000,000
Operating lease right-of-use assets												65,000,000
Property, plant and equipment												250,000,000
Finance lease liabilities (recorded in long-term debt)												$ 0
LifeLabs | Customer - related | Discount rate | Valuation, Income Approach | Minimum
Business Acquisition [Line Items]
Measurement input												0.130
LifeLabs | Customer - related | Discount rate | Valuation, Income Approach | Maximum
Business Acquisition [Line Items]
Measurement input												0.140
LifeLabs | Trade names | Discount rate | Valuation, Royalty Method
Business Acquisition [Line Items]
Measurement input												0.120
Allina Health
Business Acquisition [Line Items]
Cash consideration				$ 230,000,000
Goodwill												$ 175,000,000
Operating lease right-of-use assets												0
Property, plant and equipment												0
Finance lease liabilities (recorded in long-term debt)												0
Laboratory Business of Three Physician Groups in New York
Business Acquisition [Line Items]
Cash consideration			$ 300,000,000
Goodwill												243,000,000
Operating lease right-of-use assets												0
Property, plant and equipment												0
Finance lease liabilities (recorded in long-term debt)												0
OhioHealth
Business Acquisition [Line Items]
Cash consideration		$ 200,000,000
Goodwill												146,000,000
Operating lease right-of-use assets												0
Property, plant and equipment												0
Finance lease liabilities (recorded in long-term debt)												0
Outreach Laboratory Services Business of University Hospitals
Business Acquisition [Line Items]
Cash consideration	$ 183,000,000
Goodwill												125,000,000
Operating lease right-of-use assets												0
Property, plant and equipment												0
Finance lease liabilities (recorded in long-term debt)												$ 0
New York-Presbyterian
Business Acquisition [Line Items]
Goodwill deductible for tax purposes										$ 222,000,000
Cash consideration										275,000,000
Goodwill										222,000,000
New York-Presbyterian | Customer - related
Business Acquisition [Line Items]
Finite-lived intangibles										$ 53,000,000
Finite-lived intangible asset, useful life										15 years
Haystack Oncology, Inc.
Business Acquisition [Line Items]
Total consideration									$ 392,000,000
Contingent consideration									88,000,000
Goodwill deductible for tax purposes									0
Cash consideration									304,000,000
Goodwill									267,000,000
Cash acquired from acquisition									1,000,000
Deferred tax liabilities									23,000,000
Operating lease right-of-use assets									8,000,000
Property, plant and equipment									3,000,000
Operating lease liabilities									8,000,000
Haystack Oncology, Inc. | Discount rate
Business Acquisition [Line Items]
Measurement input												0.105
Haystack Oncology, Inc. | Technology-based intangible assets
Business Acquisition [Line Items]
Finite-lived intangibles									$ 145,000,000
Finite-lived intangible asset, useful life									15 years
Haystack Oncology, Inc. | Additional, Reimbursement Coverage
Business Acquisition [Line Items]
Contingent consideration arrangements, range of outcomes, value, high									$ 50,000,000
Pack Health, LLC
Business Acquisition [Line Items]
Total consideration											$ 123,000,000
Contingent consideration											18,000,000
Business acquisitions, net of cash acquired											105,000,000
Goodwill deductible for tax purposes											78,000,000
Finite-lived intangibles											30,000,000
Goodwill											96,000,000
Cash acquired from acquisition											4,000,000
Operating lease right-of-use assets											5,000,000
Operating lease liabilities											5,000,000
Working capital											$ (3,000,000)
Pack Health, LLC | Customer - related
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life											15 years