BUSINESS ACQUISITIONS AND DISPOSITIONS (Details) € in Millions, $ in Millions		3 Months Ended		9 Months Ended
	Jul. 22, 2025 USD ($)	Sep. 30, 2025 USD ($) Rate	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) Rate	Sep. 30, 2025 EUR (€)	Sep. 30, 2024 USD ($)
Business Combination [Line Items]
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill		$ 202.9		$ 202.9
Payments to Acquire Businesses, Net of Cash Acquired				324.0		$ 751.2
Proceeds from sale of business				0.0		13.5
Proceeds from Equity Method Investment, Distribution, Return of Capital				6.0
Gain (Loss) on Disposition of Business						4.9
Business Combination, Pro Forma Information [Line Items]
Business Combination, Pro Forma Information, Pro Forma Revenue		3,589.6	$ 3,368.4	10,531.6		10,065.6
Business Combination, Pro Forma Information, Pro Forma Income (Loss), after Tax		$ 266.1	$ 181.1	$ 728.1		$ 640.9
SYNLAB
Business Combination [Line Items]
Subsidiary, Ownership Percentage, Noncontrolling Owner | Rate		15.00%		15.00%
Customer Lists
Business Combination [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				15 years	15 years
Noncompete Agreements [Member]
Business Combination [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				4 years 9 months 18 days	4 years 9 months 18 days
BioReference Health (Oncology Focused)
Business Combination [Line Items]
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Equipment		$ 0.0		$ 0.0
Business Combination, Goodwill, Expected Tax Deductible, Amount		105.8		105.8
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill		119.2		119.2
Business Combination, Recognized Asset Acquired, Asset		225.0		225.0
Business Combination, Recognized Liability Assumed, Liability, Current		0.0		0.0
Business Combination, Recognized Liability Assumed, Other Liability, Noncurrent		32.5		32.5
Business Combination, Recognized Liability Assumed, Liability		32.5		32.5
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)		192.5		192.5
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill		192.5		192.5
Other acquirees
Business Combination [Line Items]
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Equipment		0.2		0.2
Business Combination, Goodwill, Expected Tax Deductible, Amount		74.1		74.1
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill		83.7		83.7
Business Combination, Recognized Asset Acquired, Asset		158.0		158.0
Business Combination, Recognized Liability Assumed, Liability, Current		24.0		24.0
Business Combination, Recognized Liability Assumed, Other Liability, Noncurrent		2.5		2.5
Business Combination, Recognized Liability Assumed, Liability		26.5		26.5
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)		131.5		131.5
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill		131.5		131.5
Measurement Period Adjustments
Business Combination [Line Items]
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Equipment		(0.8)		(0.8)
Business Combination, Goodwill, Expected Tax Deductible, Amount		16.8		16.8
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill		(16.0)		(16.0)
Business Combination, Recognized Asset Acquired, Asset		0.0		0.0
Business Combination, Recognized Liability Assumed, Liability, Current		0.0		0.0
Business Combination, Recognized Liability Assumed, Other Liability, Noncurrent		0.0		0.0
Business Combination, Recognized Liability Assumed, Liability		0.0		0.0
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)		0.0		0.0
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill		0.0		0.0
Total business acquisitions and adjustments
Business Combination [Line Items]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets		(0.6)		(0.6)
Business Combination, Goodwill, Expected Tax Deductible, Amount		196.7		196.7
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill		186.9		186.9
Business Combination, Recognized Asset Acquired, Asset		383.0		383.0
Business Combination, Recognized Liability Assumed, Liability, Current		24.0		24.0
Business Combination, Recognized Liability Assumed, Other Liability, Noncurrent		35.0		35.0
Business Combination, Recognized Liability Assumed, Liability		59.0		59.0
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)		324.0		324.0
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill		324.0		324.0
SYNLAB | United States of America, Dollars
Business Combination [Line Items]
Payments to Acquire Equity Method Investments				151.6
SYNLAB | Euro Member Countries, Euro
Business Combination [Line Items]
Payments to Acquire Equity Method Investments | €					€ 140.4
Community Health Systems, Inc. (Outreach Business)
Business Combination [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 195.0
Empire City Laboratories, Inc.
Business Combination [Line Items]
Payment Due at Closing		165.0		165.0
Business Combination, Contingent Consideration, Liability		$ 85.0		85.0
Payments to Acquire Businesses, Net of Cash Acquired				$ 250.0