SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of Significant Accounting Policies [Line Items]
Equity method investments carrying value	$ 462				$ 443				$ 462	$ 443
Share of equity earnings from investments in affiliates									$ 35	$ 39	$ 23
Percentage of total revenues generated by medicaid and medicare programs									16.00%	17.00%	17.00%
Purchase price discount ESPP	15.00%								15.00%
Percentage of accounts receivable due from government payers	14.00%				15.00%				14.00%	15.00%
Percentage of receivables due from patients	20.00%				17.00%				20.00%	17.00%
Operating income (loss)									$ 1,165	$ 1,277	$ 1,399
Net income	$ 267	$ 175	$ 207	$ 175	$ 167	$ 205	$ 209	$ 115	824	696	753
Trading equity securities gain or (loss)									8	3	$ 0
Gross unrealized gains from available-for-sale equity securities	0								0
Available-for-sale equity securities	2				3				2	3
Trading equity securities	58				51				58	51
Other investments	9				6				9	6
Total	$ 69				$ 60				69	60
Other Nonoperating Income (Expense) [Member]
Summary of Significant Accounting Policies [Line Items]
Other than temporary impairment losses									$ 6
Service Life [Member]
Summary of Significant Accounting Policies [Line Items]
Operating income (loss)										37
Net income										$ 23
Earnings per share, basic and diluted										$ 0.16
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	20.00%								20.00%
Finite-lived intangible asset, useful life									5 years
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	49.00%								49.00%
Finite-lived intangible asset, useful life									20 years
Building and Building Improvements [Member] | Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life									31 years 6 months
Laboratory Equipment and Furniture and Fixtures [Member] | Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life									5 years
Laboratory Equipment and Furniture and Fixtures [Member] | Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life									12 years
Software and Software Development Costs [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life									5 years	5 years	3 years
Laboratory Equipment [Member] | Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life										7 years	5 years
Laboratory Equipment [Member] | Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life										10 years	7 years
Furniture and Fixtures [Member] | Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life										5 years	3 years
Furniture and Fixtures [Member] | Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life										12 years	7 years