GUARANTEES AND CONTINGENCIES (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) complaint	May 01, 2014 matter	Jan. 06, 2012 provider
Loss Contingencies [Line Items]
Number of medical providers questioned (one or more) | provider			1
Number of matters related to a Notice of Non-Intervention | matter		1
TRICARE Contract
Loss Contingencies [Line Items]
Contract term, years	5 years
Total Medicare
Loss Contingencies [Line Items]
Percentage of premiums and services revenue	78.00%
Military services
Loss Contingencies [Line Items]
Percentage of premiums and services revenue	1.00%
Medicaid
Loss Contingencies [Line Items]
Percentage of premiums and services revenue	5.00%
Penn Treaty Insolvency | Insurance-related Assessments
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss | $	$ 54
Pending Litigation | Solak v. Broussard et al., Litwin v. Broussard et al., Scott v. Humana Inc. et al.
Loss Contingencies [Line Items]
Number of pending claims	3
Pending Litigation | Solak v. Broussard et al., Litwin v. Broussard et al., Scott v. Humana Inc. et al. | KENTUCKY
Loss Contingencies [Line Items]
Number of pending claims	2
Pending Litigation | Solak v. Broussard et al., Litwin v. Broussard et al., Scott v. Humana Inc. et al. | DELAWARE
Loss Contingencies [Line Items]
Number of pending claims	1