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%