BUSINESS ACQUISITIONS (Details) - USD ($) $ / shares in Thousands, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Feb. 19, 2015	Jan. 30, 2015	Dec. 31, 2014
Business Combination Purchase Price Allocation [Line Items]
Revenues	$ 2,368.0	$ 1,793.2
Operating Income (Loss)	$ 301.9	132.4
Proforma consolidated diluted earnings per share	$ 1,220
Other Long-term Debt	$ 715.0		$ 55.5
Other Significant Noncash Transaction, Value of Consideration Given	11.9	33.2
Net Income (Loss) Attributable to Parent	160.2	3.1
Goodwill, Acquired During Period	59.4	3,194.6
Senior Notes, Noncurrent					$ 2,900.0
Goodwill	6,252.4		$ 6,191.9			$ 3,099.4
Cash payments for laboratory-related assets	71.4	33.8
Payments to Acquire Businesses, Net of Cash Acquired	93.3	$ 3,622.2
Cash consideration				$ 780.8
Business Combination, Acquired Receivables, Fair Value				334.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory				51.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent				95.9
Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Revenues	2,146.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets				12.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets				8,054.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable				190.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities				306.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue				168.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent				879.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt				250.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other				109.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				1,904.0
Operating Income (Loss)	$ 272.4
Basic Earnings Per Share, Pro Forma	$ 1,230
Net Income (Loss) Attributable to Parent	$ 125.1
Total acquisition consideration (cash and non-cash)				6,150.7
Cash consideration				780.8
Business Combination, Acquired Receivables, Fair Value				334.8
Unbilled Receivables, Current				138.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory				51.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent				34.4
Covance [Member] | Depreciation Expense [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Items		1.9
Covance [Member] | Amortization expense [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Items		.3
Covance [Member] | Interest Expense [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Items		.2
Covance [Member] | Other Comprehensive Income (Loss) [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Items		122.2	102.7
Liabilities, Total [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	205.7
Other Liabilities [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	30.5
Senior Notes [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
Deferred income tax liability [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	149.1
Deferred Revenue [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
Accrued Liabilities [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	26.1
Accounts Payable [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
Assets, Total [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	205.7
Other Assets [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	-3.2
Goodwill [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	-82.4
Property, Plant and Equipment [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	174
Deferred tax asset [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	61.5
Prepaid Expenses and Other Current Assets [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	86.5
Inventories [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
Accounts Receivable [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
Cash and Cash Equivalents [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
unbilled services [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination Purchase Price Allocation [Table Text Block]	0
Goodwill [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				3,093.7
Scenario, Previously Reported [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets				7,849.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent				730.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other				78.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				1,698.3
Scenario, Previously Reported [Member] | Accounts Payable [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				190.8
Scenario, Previously Reported [Member] | Prepaid Expenses and Other Current Assets [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				261.4
Scenario, Previously Reported [Member] | Accrued Liabilities [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				280.8
Scenario, Previously Reported [Member] | Other Assets [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				15.2
Scenario, Previously Reported [Member] | Goodwill [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				3,176.1
Use Rights [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				0.0
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	8 years
Use Rights [Member] | Scenario, Previously Reported [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				4.9
Trademarks and Trade Names [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	15 years
Customer Relationships [Member]
Business Combination Purchase Price Allocation [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	27 years
Customer Relationships [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment				1,018.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				1,830.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				347.9
Customer Relationships [Member] | Scenario, Previously Reported [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment				844.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				1,917.2
Software and Software Development Costs [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				74.5
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Software and Software Development Costs [Member] | Scenario, Previously Reported [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				0.0
Off-Market Favorable Lease [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				5.5
Off-Market Favorable Lease [Member] | Scenario, Previously Reported [Member] | Covance [Member]
Business Combination Purchase Price Allocation [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 0.0