ACQUISITIONS AND DIVESTITURES - Additional Information (Detail) - USD ($) $ in Millions			12 Months Ended
	Jun. 01, 2015	Sep. 06, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Gain on sale of business			$ 270	$ 0	$ 0
Liabilities
Net assets disposed	$ 763			737
Goodwill			$ 3,265	3,231	3,253
Weighted Average Life			9 years 9 months 18 days
American Eldercare Inc.
Liabilities
Goodwill		$ 76
Other intangible assets acquired		$ 75
Weighted Average Life		9 years 3 months 18 days
Concentra Inc.
Business Acquisition [Line Items]
Selling price in cash	1,055
Disposal transaction costs	22
Assets
Receivables, net	130			115
Property and equipment, net	197			191
Goodwill	480			480
Other intangible assets, net	124			132
Other assets	27			25
Total assets disposed/held-for-sale	958			943
Liabilities
Trade accounts payable and accrued expenses	81			90
Other liabilities	114			116
Total liabilities disposed/held-for-sale	$ 195			206
Pre-tax earnings			$ 411	$ 998	$ 981