GOODWILL AND OTHER INTANGIBLE ASSETS - Details of Intangible Assets Included in Other Long-Term Assets (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	9 years 9 months 18 days
Cost	$ 754	$ 753
Accumulated Amortization	527	473
Net	$ 227	280
Customer contracts/ relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	9 years 9 months 18 days
Cost	$ 566	566
Accumulated Amortization	388	347
Net	$ 178	219
Trade names and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	8 years 2 months 12 days
Cost	$ 104	104
Accumulated Amortization	77	69
Net	$ 27	35
Provider contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	14 years 1 month 6 days
Cost	$ 51	51
Accumulated Amortization	33	29
Net	$ 18	22
Noncompetes and other
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	8 years 1 month 12 days
Cost	$ 33	32
Accumulated Amortization	29	28
Net	$ 4	$ 4