WellCare Health Plans 10-Q 31 Jul 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	WELLCARE HEALTH PLANS, INC.
Entity Central Index Key	1,279,363
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		44,767,364
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Premium	$ 4,612.6	$ 4,293.6	$ 9,238.9	$ 8,240.6
Investment and other income	26.4	11.4	46.3	18.6
Total revenues	4,639	4,305	9,285.2	8,259.2
Expenses:
Medical benefits	3,866	3,719	7,828	7,197.6
Selling, general and administrative	377.9	365.5	733.8	667.9
ACA industry fee	79	0	160.5	0
Medicaid premium taxes	30.6	31.2	62.7	61.1
Depreciation and amortization	34.5	29.3	70.9	53.2
Interest	17.1	18.1	34.2	34.3
Total expenses	4,405.1	4,163.1	8,890.1	8,014.1
Income from operations	233.9	141.9	395.1	245.1
Loss on extinguishment of debt	0	26.1	0	26.1
Income before income taxes and equity in losses of unconsolidated subsidiaries	233.9	115.8	395.1	219
Equity in losses of unconsolidated subsidiaries	(4)	(1.1)	(6.7)	(1.1)
Income before income taxes	229.9	114.7	388.4	217.9
Income tax expense	78.3	40.6	135.1	76.5
Net income	151.6	74.1	253.3	141.4
Other comprehensive income (loss), before tax:
Change in net unrealized gains and losses on available-for-sale securities	0	1.2	(10.3)	1.3
Income tax expense (benefit) related to other comprehensive income	0	0.4	(2.4)	0.4
Other comprehensive income (loss), net of tax	0	0.8	(7.9)	0.9
Comprehensive income	$ 151.6	$ 74.9	$ 245.4	$ 142.3
Earnings per common share:
Basic (in USD per share)	$ 3.39	$ 1.67	$ 5.67	$ 3.18
Diluted (in USD per share)	$ 3.35	$ 1.65	$ 5.60	$ 3.15
Weighted average common shares outstanding:
Basic (in shares)	44,759,808	44,498,610	44,682,850	44,432,299
Diluted (in shares)	45,282,294	44,934,051	45,239,210	44,880,357

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 5,098.5	$ 4,198.6
Short-term investments	793.5	469.5
Premiums receivable, net	700.1	453.4
Pharmacy rebates receivable, net	433.1	335
Receivables from government partners	77.2	44.2
Funds receivable for the benefit of members	29	27.5
Deferred ACA industry fee	160.5	0
Prepaid expenses and other current assets, net	311.1	291
Total current assets	7,603	5,819.2
Property, equipment and capitalized software, net	331.1	319.5
Goodwill	677.4	660.7
Other intangible assets, net	346.6	367.9
Long-term investments	722	766.2
Restricted cash, cash equivalents and investments	229.3	211
Other assets	11.9	4.9
Assets of discontinued operations	213.1	215.2
Total Assets	10,134.4	8,364.6
Current Liabilities:
Medical benefits payable	2,345.4	2,146.3
Unearned premiums	580	65.9
ACA industry fee liability	321	0
Accounts payable and accrued expenses	604.1	788.1
Funds payable for the benefit of members	1,674.5	1,075.9
Other payables to government partners	452.3	367
Total current liabilities	5,977.3	4,443.2
Deferred income tax liability, net	56.1	93.4
Long-term debt, net	1,183.8	1,182.4
Other liabilities	32.2	13.7
Liabilities of discontinued operations	213.1	215.2
Total Liabilities	7,462.5	5,947.9
Commitments and contingencies	0	0
Stockholders' Equity:
Preferred stock, $0.01 par value (20,000,000 authorized, no shares issued or outstanding)	0	0
Common stock, $0.01 par value (100,000,000 authorized, 44,767,277 and 44,522,988 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively)	0.4	0.4
Paid-in capital	601.3	591.5
Retained earnings	2,080.8	1,827.5
Accumulated other comprehensive loss	(10.6)	(2.7)
Total Stockholders' Equity	2,671.9	2,416.7
Total Liabilities and Stockholders' Equity	$ 10,134.4	$ 8,364.6

CONDENSED CONSOLIDATED BALANCE4

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Stockholders' Equity:
Preferred stock, par value (in USD per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	20,000,000	20,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	44,767,277	44,522,988
Common stock, outstanding (in shares)	44,767,277	44,522,988

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2016		44,293,881
Beginning balance at Dec. 31, 2016	$ 2,000.1	$ 0.4	$ 546.9	$ 1,453.8	$ (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for vested stock-based compensation awards (in shares)		308,130
Repurchase and retirement of shares to satisfy tax withholding requirements (in shares)		(94,189)
Repurchase and retirement of shares to satisfy tax withholding requirements	(13.6)		(13.6)
Stock-based compensation expense, net of forfeitures	23.5		23.5
Comprehensive income	142.3			141.4	0.9
Ending balance (in shares) at Jun. 30, 2017		44,507,822
Ending balance at Jun. 30, 2017	$ 2,152.3	$ 0.4	556.8	1,595.2	(0.1)
Beginning balance (in shares) at Dec. 31, 2017	44,522,988	44,522,988
Beginning balance at Dec. 31, 2017	$ 2,416.7	$ 0.4	591.5	1,827.5	(2.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for vested stock-based compensation awards (in shares)		349,225
Repurchase and retirement of shares to satisfy tax withholding requirements (in shares)		(104,936)
Repurchase and retirement of shares to satisfy tax withholding requirements	(20.3)		(20.3)
Stock-based compensation expense, net of forfeitures	30.1		30.1
Comprehensive income	$ 245.4			253.3	(7.9)
Ending balance (in shares) at Jun. 30, 2018	44,767,277	44,767,277
Ending balance at Jun. 30, 2018	$ 2,671.9	$ 0.4	$ 601.3	$ 2,080.8	$ (10.6)

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income		$ 253.3	$ 141.4
Adjustments to reconcile net income to cash flows from operating activities:
Depreciation and amortization		70.9	53.2
Loss on extinguishment of debt		0	26.1
Stock-based compensation expense		30.1	23.5
Deferred taxes, net		(36.9)	(34.5)
Other, net		7.7	7.3
Changes in operating accounts, net of effects from acquisitions:
Premiums receivable, net		(251.2)	(480.8)
Pharmacy rebates receivable, net		(98.1)	(50.7)
Medical benefits payable		199.1	186.4
Unearned premiums		514.1	537.6
Other payables to government partners		52.3	(20.7)
Accrued liabilities and other, net		35.3	(53.9)
Net cash provided by operating activities		776.6	334.9
Cash flows from investing activities:
Acquisitions and acquisition-related settlements, net of cash acquired		0	(717.9)
Purchases of investments		(696.8)	(740)
Proceeds from sales and maturities of investments		383.1	181.9
Additions to property, equipment and capitalized software, net		(52.5)	(54.4)
Net cash used in investing activities		(366.2)	(1,330.4)
Cash flows from financing activities:
Proceeds from issuance of debt, net of financing costs paid		0	1,182.2
Payments on debt		0	(1,026.1)
Repurchase and retirement of shares to satisfy employee tax withholding requirements		(20.3)	(13.6)
Funds received for the benefit of members, net		491.5	834.4
Other, net		14.8	(9.1)
Net cash provided by financing activities		486	967.8
Increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents		896.4	(27.7)
Balance at beginning of period	[1]	4,263	4,121.3
Balance at end of period	[1]	5,159.4	4,093.6
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for taxes, net of refunds		86.9	94.9
Cash paid for interest		32.8	22.5
SUPPLEMENTAL DISCLOSURES OF NON-CASH TRANSACTIONS:
Non-cash additions to property, equipment, and capitalized software		$ 4.9	$ 3.5
[1]	Beginning and ending cash, cash equivalents and restricted cash and cash equivalents balances have been retrospectively adjusted to reflect the adoption of ASU 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash" effective January 1, 2018. See Note 1 - Organization, Basis of Presentation and Significant Accounting Policies for further discussion.

ORGANIZATION, BASIS OF PRESENTA

ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES WellCare Health Plans, Inc. (the "Company", "we", "us", or "our") is a leading managed care company, headquartered in Tampa, Florida, focusing exclusively on providing government-sponsored managed care services, primarily through Medicaid, Medicare Advantage ("MA") and Medicare Prescription Drug Plans ("PDPs") to families, children, seniors, and individuals with complex medical needs. As of June 30, 2018 , we served approximately 4.4 million members in 50 states and the District of Columbia. We estimate that we are among the largest managed care organizations providing Medicaid managed care services plans, MA Plans and PDPs, as measured by membership. Our broad range of experience and government focus allows us to effectively serve our members, partner with our providers, government clients and communities we serve, and efficiently manage our ongoing operations. As of June 30, 2018 , we operated Medicaid health plans, including states where we receive Medicaid premium revenues associated with dually eligible special needs plans, in Arizona, Florida, Georgia, Hawaii, Illinois, Kentucky, Missouri, Nebraska, New Jersey, New York, South Carolina and Texas. In addition, as of June 30, 2018 , we also operated MA coordinated care plans ("CCPs") in Arizona, Arkansas, California, Connecticut, Florida, Georgia, Hawaii, Illinois, Kentucky, Louisiana, Maine, Mississippi, New Jersey, New York, North Carolina, South Carolina, Tennessee and Texas. We also offered stand-alone Medicare PDPs in 50 states and the District of Columbia. Basis of Presentation The accompanying unaudited condensed consolidated balance sheets and statement of comprehensive income, changes in stockholder's equity, and cash flows include our accounts and the accounts of our subsidiaries over which we have control or are the primary beneficiary. We eliminated all intercompany accounts and transactions. The accompanying unaudited condensed consolidated interim financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP"). Accordingly, certain financial information and footnote disclosures normally included in financial statements prepared in accordance with GAAP, but that are not required for interim reporting purposes, have been condensed or omitted. The accompanying unaudited condensed consolidated interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto, for the fiscal year ended December 31, 2017 , included in our Annual Report on Form 10-K ("2017 Form 10-K"), which was filed with the U.S. Securities and Exchange Commission ("SEC") in February 2018. Results for the interim periods presented are not necessarily indicative of results that may be expected for the entire year or any other interim period. In the opinion of management, the interim financial statements reflect all normal recurring adjustments that we consider necessary for the fair presentation of our financial position, results of operations and cash flows for the interim periods presented. In accordance with GAAP, we make certain estimates and assumptions that affect the amounts reported in the condensed consolidated interim financial statements and accompanying notes. We base these estimates, including assumptions as to the annualized tax rate, on our knowledge of current events and anticipated future events and evaluate and update our assumptions and estimates on an ongoing basis; however, actual results may differ from our estimates. We evaluated all material events subsequent to the date of these condensed consolidated interim financial statements. Certain reclassifications were made to 2017 financial information to conform to the 2018 presentation. Unconsolidated Subsidiaries In April 2017, in connection with the acquisition of Universal American Corp. (“Universal American”), we acquired a wholly-owned subsidiary, which works with physicians and other health care professionals to operate Accountable Care Organizations ("ACOs") under the Medicare Shared Saving Program ("MSSP") and Next Generation ACO Models. ACOs were established by the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010 (the "ACA") to reward integrated, efficient care and allow providers to share in any savings they achieve as a result of improved quality and operational efficiency. These ACOs are generally formed as limited liability companies. The ACOs are considered variable interest entities ("VIEs") under GAAP as these entities do not have sufficient equity to finance their own operations without additional financial support. We own a majority interest in our ACOs; however, we share the power to direct the activities that most significantly affect the ACOs with health care providers that are minority owners in the ACOs. This power is shared pursuant to the structure of the management committee of each of the ACOs. Accordingly, we have determined that we are not the primary beneficiary of the ACOs; therefore, we cannot consolidate their results. We perform an ongoing qualitative assessment of our variable interests in VIEs to determine whether we have a controlling financial interest and would therefore be considered the primary beneficiary of the VIE. We account for our participation in the ACOs using the equity method. Gains and losses are immaterial and are reported on the face of our condensed consolidated statements of comprehensive income as equity in (losses) earnings of unconsolidated subsidiaries. Significant Accounting Policies Below is a discussion of our significant accounting policies which affected the comparability of our consolidated results of operations, financial condition or cash flows for the periods presented. Refer to Note 2 - Summary of Significant Accounting Policies to the Consolidated Financial Statements included in our 2017 Form 10-K for a complete discussion of all of our significant accounting policies. Premium Receivables and Unearned Premiums We record premiums earned but not received as premiums receivable and record premiums received in advance of the period of service as unearned premiums in our condensed consolidated balance sheets. A complete discussion of premiums receivable and unearned premiums is included in Note 2 - Summary of Significant Accounting Policies to the Consolidated Financial Statements included in our 2017 Form 10-K. The premium receivable balance at June 30, 2018 is primarily related to Medicaid contracts with our state partners of approximately $442.3 million , as well as risk-adjusted premiums receivable under our MA and PDP contracts of approximately $244.4 million . Unearned premiums at June 30, 2018 consist primarily of the July 2018 CMS Medicare premium advance of approximately $540.6 million . Medicaid Risk-Adjusted Premiums and Retroactive Rate Changes As discussed further in Note 2 - Summary of Significant Accounting Policies to the Consolidated Financial Statements included in our 2017 Form 10-K, Medicaid premium rate changes are recognized in the period the change becomes effective, when the effect of the change in the rate is reasonably estimable and collection is assured. In some instances, our Medicaid premiums are subject to risk score adjustments based on the health profile of our membership. Generally, the risk score is determined by the state agency's analysis of encounter submissions of processed claims data to determine the acuity of our membership relative to the entire state's Medicaid membership. The frequency of when states adjust premiums varies, but is usually done quarterly or semi-annually on a retrospective basis. We recognize periodic changes to risk-adjusted premiums as revenue when the amounts are determinable and collection is reasonably assured. As of June 30, 2018 , our condensed consolidated balance sheet included a net receivable from our Medicaid state partners of $8.7 million related to retroactive rate changes and risk score adjustments, compared with a net payable to our Medicaid state partners of $50.7 million as of December 31, 2017. Medicare Part D Settlements We receive certain Part D prospective subsidy payments from the Centers for Medicare & Medicaid Services ("CMS") for our MA and PDP members as a fixed monthly per member amount, based on the estimated costs of providing prescription drug benefits over the plan year, as reflected in our bids. A discussion of the subsidy components under Part D is included in Note 2 - Summary of Significant Accounting Policies to the Consolidated Financial Statements included in our 2017 Form 10-K. CMS will fully reimburse these subsidies, or recoup overpaid subsidies made during the plan year, as part of its annual settlement process that typically occurs in the fourth quarter of the subsequent year and, accordingly, there is no insurance risk to us. Therefore, amounts received for these subsidies are not considered premium revenue, and are reported, net of the subsidy benefits paid, as Funds receivable (payable) for the benefit of members in the condensed consolidated balance sheets. As of June 30, 2018 , our condensed consolidated balance sheet includes CMS Part D payables for the 2018, 2017 and 2016 plan years, including a $341.2 million advance receipt of the July 2018 CMS Medicare subsidy payments in June 2018, and a net receivable relating to the 2015 plan year. As of December 31, 2017, our condensed consolidated balance sheet included CMS Part D payables primarily related to the 2017 and 2016 plan years, as well as a net receivable relating to the 2015 plan year. ACA Industry Fee The ACA imposed certain new taxes and fees, including an annual premium-based health insurance industry assessment (the "ACA industry fee") on health insurers, which began in 2014. In December 2015, President Obama signed the Consolidated Appropriations Act, 2016 which, among other provisions, included a one-year moratorium on the ACA industry fee for 2017, which also eliminated the associated Medicaid ACA industry fee reimbursements from our state government partners for 2017. Accordingly, we did not incur ACA industry fee expense nor recognize any Medicaid ACA industry fee reimbursement revenue for the three and six months ended June 30, 2017 . For 2018, we accrued the estimated liability as of January 1, 2018, with a corresponding Deferred ACA industry fee asset on the condensed consolidated balance sheet that is being amortized to expense on a straight line basis. As of June 30, 2018 , our accrued estimated liability for the 2018 ACA industry fee was $321.0 million . We incurred $79.0 million and $160.5 million of such amortization as ACA industry fee expense for the three and six months ended June 30, 2018 , respectively. Additionally, we recognized $62.8 million and $127.5 million of Medicaid ACA industry fee reimbursement revenue for the three and six months ended June 30, 2018 , respectively. While the ACA industry fee is being assessed in 2018, the continuing spending resolution passed into law in January 2018 provides for an additional one-year moratorium for the ACA industry fee in 2019. Recently Adopted Accounting Standards In May 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-09, " Compensation-Stock Compensation (Topic 718) - Scope of Modification Accounting ". This guidance addresses which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting pursuant to Topic 718. An entity should account for the effects of a modification unless (a) the fair value of the modified award is the same as the fair value of the original award, (b) the vesting conditions of the modified award are the same as the vesting conditions of the original award and (c) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments in this guidance should be applied prospectively for public business entities effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In January 2017, the FASB issued ASU 2017-04, " Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ". This update eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge. As a result, an entity should perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In January 2017, the FASB issued ASU 2017-01, “ Business Combinations (Topic 805): Clarifying the Definition of a Business ”. The amendments in this update provide guidance to assist entities with evaluating when a group of transferred assets and activities (collectively referred to as a "set") is a business. This new guidance provides for a "screen", which requires a determination that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. If the screen's threshold is not met, a set cannot be considered a business unless it includes an input and a substantive process that together significantly contribute to the ability to create output, eliminating the evaluation of whether a market participant could replace missing elements. This guidance is effective for prospective business combinations for public entities for interim and annual periods beginning after December 15, 2017. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In November 2016, the FASB issued ASU 2016-18, “ Statement of Cash Flows (Topic 230) Restricted Cash; a consensus of the FASB Emerging Issues Task Force ”. This update requires entities to reconcile, on the statement of cash flows, changes in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. We adopted this guidance retrospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 and 2017 , respectively. The following table provides a reconciliation of cash, cash equivalents and restricted cash and cash equivalents as reported within the condensed consolidated balance sheets to the total of the same such amounts shown within the condensed consolidated statements of cash flows: As of June 30, 2018 December 31, 2017 Cash and cash equivalents $ 5,098.5 $ 4,198.6 Restricted cash and cash equivalents (1) 60.9 64.4 Total cash, cash equivalents, and restricted cash and cash equivalents $ 5,159.4 $ 4,263.0 (1) Restricted cash and cash equivalents consist of restricted cash and restricted money market funds and are included in Restricted cash, cash equivalents and investments within noncurrent assets of our condensed consolidated balance sheets. Refer to Note 6 - Restricted Cash, Cash Equivalents and Investments for further detail. In August 2016, the FASB issued ASU 2016-15, " Statement of Cash Flows Classification of Certain Cash Receipts and Cash Payments (Topic 230) ". This update targets eight specific areas to clarify how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This guidance is effective for public entities for interim and annual periods beginning after December 15, 2017, with early adoption permitted. We adopted this guidance on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In January 2016, the FASB issued ASU 2016-01, " Financial Instrument - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, " which requires entities to measure equity securities that are not consolidated or accounted for under the equity method at fair value through net income. This amendment also simplifies the impairment test of equity investments without readily determinable fair values. In February 2018, the FASB issued ASU 2018-03, " Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, " which clarifies that an entity that uses the measurement alternative for equity securities without readily determinable fair values can change its measurement approach to fair value. This guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In May 2014, the FASB issued ASU 2014-09, " Revenue from Contracts with Customers (Topic 606) ". ASU 2014-09 supersedes existing revenue recognition standards with a single model unless those contracts are within the scope of other standards (e.g., an insurance entity’s insurance contracts). The revenue recognition principle in ASU 2014-09 requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, new and enhanced disclosures are required. We adopted this guidance prospectively on January 1, 2018. Given that substantially all of our revenues are derived from insurance contracts accounted for in accordance with ASC 944, Financial Services-Insurance , which are specifically excluded from the scope of ASU 2014-09, the adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . Accounting Standards Pending Adoption In February 2018, the FASB issued ASU 2018-02 " Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income", which allows entities to reclassify stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 from accumulated other comprehensive income to retained earnings. The guidance is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. We are currently assessing the effect this guidance will have on our consolidated results of operations, financial condition or cash flows. In March 2017, the FASB issued ASU 2017-08, " Receivables – Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities ". This update shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. Currently, entities generally amortize the premium as a yield adjustment over the contractual life of the security. The new guidance does not change the accounting for purchased callable debt securities held at a discount. This guidance is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. We are currently assessing the effect this guidance will have on our consolidated results of operations, financial condition or cash flows. In June 2016, the FASB issued ASU 2016-13, " Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, " which requires entities to use a current expected credit loss model, which is a new impairment model based on expected losses rather than incurred losses. Under this model, an entity would recognize an impairment allowance equal to its current estimate of all contractual cash flows that the entity does not expect to collect from financial assets measured at amortized cost. The entity's estimate would consider relevant information about past events, current conditions, and reasonable and supportable forecasts, which will result in recognition of lifetime expected credit losses upon loan origination. ASU 2016-13 is effective for interim and annual reporting periods beginning after December 15, 2019, with early adoption permitted for annual reporting periods beginning after December 15, 2018. We are currently assessing the effect this guidance will have on our consolidated results of operations, financial condition or cash flows. In February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842), " which for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments in its balance sheet. This standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term, on a generally straight-line basis. This guidance is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. We do not expect the adoption of this guidance to have a material effect on our consolidated results of operations or cash flows. The effect of ASU 2016-02 on our consolidated financial position will be based on leases outstanding at the time of adoption.

ACQUISITIONS

ACQUISITIONS	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Meridian Pending Acquisition In May 2018, we announced that we entered into a definitive agreement to acquire Meridian Health Plan of Michigan, Inc., Meridian Health Plan of Illinois, Inc. and MeridianRx, a pharmacy benefit manager ("PBM") (collectively "Meridian"), for approximately $2.5 billion in cash (the "Meridian Acquisition"). The transaction is expected to close in the next few months, subject to customary closing conditions, including regulatory approvals. As a result of this transaction, we will diversify our Medicaid portfolio through the addition of Michigan, where Meridian has the leading market position and industry-leading quality; deepen our Medicaid presence in Illinois; and acquire an integrated PBM platform. Meridian serves approximately 1.1 million Medicaid, MA, integrated dual-eligible and Health Insurance Marketplace members as of May 1, 2018 in Michigan, Illinois, Indiana and Ohio. We expect to fund the Meridian Acquisition through a combination of cash on hand, our undrawn $1.3 billion revolving credit facility, and, subject to market conditions, new debt of $600.0 million to $1.0 billion and new equity of $800 million to $1.2 billion . The transaction is not contingent upon financing, and WellCare has secured $2.5 billion in committed bridge financing. Phoenix Health Plan Assets Acquisition On May 1, 2017, we completed our acquisition of certain assets from Phoenix Health Plan ("PHP"), including Arizona Medicaid membership and certain provider contracts. The transaction included the transfer of approximately 42,000 Medicaid members to our Arizona health plan. The transaction was funded with available cash on hand. Universal American Acquisition On April 28, 2017 (the "Effective Date"), we acquired all of the issued and outstanding shares of Universal American. The transaction was valued at approximately $770.0 million , including the cash purchase price of $10.00 per outstanding share ("Per Share Merger Consideration") of Universal American's common stock, the assumption of $145.3 million fair value of Universal American's convertible debt, the cash settlement of Universal American's $40.0 million par value of Series A Mandatorily Redeemable Preferred Shares (the "Preferred Shares") and the cash settlement of outstanding vested and unvested stock-based compensation awards. The acquisition of Universal American, with approximately 119,000 MA members in Texas, New York and Maine, strengthens our business by increasing our MA membership by one-third, deepening our presence in two key markets, Texas and New York, and diversifying our business portfolio. In addition, Universal American joined with provider groups to operate ACOs under the MSSP and Next Generation ACO models. The fair value at the Effective Date of the consideration transferred in the Universal American acquisition consisted of the following: (in millions) Number of shares of Universal American common stock outstanding on April 28, 2017 (57.1 million) multiplied by the Per Share Merger Consideration $ 570.8 Assumed debt (a) 145.3 Repurchase of Preferred Shares (b) 41.0 Stock-based award cash consideration (c) 12.9 Total consideration transferred $ 770.0 (a) Following the consummation of the Universal American transaction, all of the holders of Universal American's 4.00% convertible senior notes (the "Convertible Notes") elected to convert their notes into the right to receive cash equal to the par value of the notes plus a make whole premium. We paid the noteholders the amounts due and all of the Convertible Notes were redeemed in the second quarter of 2017. The fair value of the Convertible Notes was determined based on quoted market prices; therefore, have been classified within Level 1 of the fair value hierarchy. See Universal American Convertible Notes below for further discussion of the repurchase of the Convertible Notes. (b) On the Effective Date, we redeemed an aggregate of $40.0 million of Universal American's Preferred Shares, which became redeemable by the holders on April 28, 2017, due to certain change in control provisions for the Preferred Shares. We redeemed the Preferred Shares for $41.0 million, which includes the $40.0 million par value of the Preferred Shares and $1.0 million of accrued dividends. See Universal American Mandatorily Redeemable Preferred Shares below for further discussion of the redemption of the Preferred Shares. (c) Pursuant to the terms of the Universal American acquisition, outstanding vested and unvested stock-based compensation awards as of the Effective Date converted to the right to receive cash. We estimated the fair value of these awards at the Effective Date and attributed that fair value to pre-acquisition and post-acquisition services in accordance with GAAP. Accordingly, $12.9 million of the fair value of these awards was attributed to pre-acquisition services and is included in the estimated consideration transferred, and approximately $20.0 million has been, or will be, included in our post-acquisition financial statements as compensation costs and reflected as a selling, general and administrative expense in our condensed consolidated statements of comprehensive income. The following table summarizes the final fair values of major classes of assets acquired and liabilities assumed at the Effective Date, based on our valuation assumptions, reconciled to the total consideration transferred. Assets (in millions) Cash and cash equivalents $ 66.4 Investments, including restricted investments 254.4 Premiums receivable, net 90.7 Pharmacy rebates receivable, net, and other current assets 45.6 Property, equipment and capitalized software, net 7.5 Goodwill 292.3 Other intangible assets, net 298.2 Assets of discontinued operations 219.6 Fair value of total assets acquired $ 1,274.7 Liabilities Medical benefits payable 128.1 Deferred tax liabilities, net 70.1 Other liabilities 87.8 Liabilities of discontinued operations 218.7 Fair value of liabilities assumed $ 504.7 Fair value of net assets acquired $ 770.0 The fair value results from judgments about future events, which reflect certain uncertainties and rely on estimates and assumptions. The judgments used to determine the fair value assigned to each class of assets acquired and liabilities assumed, as well as intangible asset lives, can materially affect our operating results. As of the Effective Date, the expected fair value of all current assets and liabilities, as well as assets and liabilities of discontinued operations (refer to Note 12 - Discontinued Operations for further discussion), approximated their historical cost. For certain noncurrent assets and liabilities, we have made fair value adjustments based on information reviewed through April 2018, the end of the measurement period. Significant fair value adjustments are noted as follows. Identifiable intangible assets acquired The following table summarizes the final fair values and weighted average useful lives for identifiable intangible assets acquired in the Universal American acquisition, as of the Effective Date. Gross Fair Value (in millions) Weighted Average Useful Life (in years) Membership $ 240.0 10.0 Tradenames 36.0 13.9 Provider network 9.5 15.0 Other 12.7 6.2 Total $ 298.2 10.5 We valued the acquired membership and tradename intangible assets using an income approach (discounted future cash flow analysis) based on our consideration of historical financial results and expected industry and market trends. We discounted the future cash flows by a weighted-average cost of capital based on an analysis of the cost of capital for comparable companies within our industry. We valued the acquired provider network using a cost approach, which utilizes cost assumptions applicable at the valuation date to determine the cost of constructing a similar asset. Our other intangible assets include acquired operating licenses, certain non-compete agreements and acquired technology, which were valued using a combination of income and cost approaches. We amortize the intangible assets over the period we expect these assets to contribute directly or indirectly to our future cash flows on a straight-line basis, which approximates the expected pattern of economic consumption over their estimated useful lives. Deferred taxes The purchase price allocation includes net deferred tax liabilities of $70.1 million , primarily relating to deferred tax liabilities established on the identifiable acquired intangible assets, partially offset by deferred tax assets acquired in the Universal American transaction. Goodwill We recorded $292.3 million for the valuation of goodwill, assigned to our Medicare Health Plans reportable segment, for the excess of the purchase price over the estimated fair value of the net assets acquired. The recorded goodwill and other intangible assets related to the acquisition are not deductible for tax purposes. Universal American Convertible Notes In 2016, Universal American completed the offering of $115.0 million of their 4.00% Convertible Notes due 2021. The acquisition by WellCare constituted a “Make-Whole Fundamental Change” under the indenture for the Convertible Notes. During the three months ended June 30, 2017, all of the holders of the Convertible Notes elected to convert their notes into the right to receive cash equal to the par value of the notes plus a make-whole premium. We paid the noteholders the amounts due and all of the Convertible Notes were redeemed during the second quarter of 2017. The fair value of the Convertible Notes was $145.3 million on the Effective Date and was included in the purchase consideration for the Universal American acquisition. Universal American Mandatorily Redeemable Preferred Shares In April 2011, Universal American issued an aggregate of $40.0 million of its Preferred Shares, representing 1,600,000 shares with a par value of $0.01 per share and a liquidation preference of $25.00 per share. During the three months ended June 30, 2017, the Preferred Shares were redeemed for $41.0 million , which includes the $40.0 million par value of the Preferred Shares and $1.0 million of accrued dividends. The $41.0 million redemption amount was included in the purchase consideration for the Universal American acquisition. Condensed Consolidated Statement of Comprehensive Income We included the results of Universal American's operations after the Effective Date in our condensed consolidated financial statements. The amount of premium revenue attributable to Universal American included in our condensed consolidated statement of comprehensive income, for the three and six months ended June 30, 2018 , was $385.1 million and $769.9 million , respectively. Additionally, our condensed consolidated statement of comprehensive income for the three and six months ended June 30, 2018 included pretax income of $13.0 million and $31.7 million , respectively, attributable to Universal American's operations, which includes transaction and integration-related costs of $1.2 million and $3.9 million , respectively, related to the ongoing integration of the operations. These costs include severance payments, and advisory, legal and other professional fees that are reflected in selling, general and administrative ("SG&A") expense in our condensed consolidated statement of comprehensive income. During the three and six months ended June 30, 2017, the amount of revenue and pre-tax losses attributable to Universal American included in our condensed consolidated statement of comprehensive income was $235.1 million and $31.7 million , respectively. These results include transaction and integration-related costs of $26.7 million , of which $25.6 million were incurred during the three months ended June 30, 2017. These costs include severance payments, and advisory, legal and other professional fees that are reflected in SG&A expense in our condensed consolidated statement of comprehensive income. Unaudited Pro Forma Financial Information The results of operations and financial condition for our 2017 acquisitions have been included in our condensed consolidated financial statements since the respective acquisition dates. The unaudited pro forma financial information presented below reflects our 2017 acquisitions of PHP and Universal American assuming the acquisitions occurred as of January 1, 2017. Proforma results are not provided for the three and six months ended June 30, 2018, as our 2017 acquisitions were included in our results of operations for the three and six months ended June 30, 2018. These pro forma results are based on estimates and assumptions and do not reflect any anticipated synergies, efficiencies or other cost savings that we expect to realize from the acquisitions. The following unaudited pro forma results have been prepared for comparative purposes only and do not purport to be indicative of the results of operations that would have occurred had the acquisitions actually consummated at January 1, 2017, or project the future results of the combined company. Three Months Ended June 30, Six Months Ended June 30, (in millions, except per share data) 2017 2017 Total revenues $ 4,690.8 $ 8,415.1 Net income $ 92.6 $ 151.8 Earnings per common share: Basic $ 2.08 $ 3.42 Diluted $ 2.06 $ 3.38 The pro forma results presented in the schedule above include adjustments related to the following purchase accounting and other acquisition-related costs: • Elimination of historical intangible asset amortization expense and addition of amortization expense based on the current preliminary values of identified intangible assets; • Elimination of interest expense associated with retired Universal American obligations; • Elimination of transaction and integration-related costs; • Elimination of Universal American discontinued operations; • Adjustments to align the acquisitions to our accounting policies; and • Tax effects of the adjustments noted above.

SEGMENT REPORTING

SEGMENT REPORTING	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING On a regular basis, we evaluate discrete financial information and assess the performance of our three reportable segments, Medicaid Health Plans, Medicare Health Plans and Medicare PDPs, to determine the most appropriate use and allocation of Company resources. We allocate premium revenue, medical benefits expense, the ACA industry fee incurred in 2018 and goodwill to our reportable segments. We do not allocate to our reportable segments any other assets and liabilities, investment and other income, selling, general and administrative expenses, depreciation and amortization, or interest expense. The Company's decision-makers primarily use premium revenue, medical benefits expense and gross margin to evaluate the performance of our reportable segments. Medicaid Health Plans Our Medicaid Health Plans segment includes plans for beneficiaries of Temporary Assistance for Needy Families ("TANF"), Supplemental Security Income ("SSI"), Aged Blind and Disabled ("ABD") and other state-based programs that are not part of the Medicaid program, such as Children's Health Insurance Program ("CHIP") and Long-Term Services and Supports ("LTSS") programs. TANF generally provides assistance to low-income families with children. ABD and SSI generally provide assistance to low-income aged, blind or disabled individuals. CHIP provides assistance to qualifying families who are not eligible for Medicaid because their income exceeds the applicable income thresholds. The LTSS program is designed to help people with chronic illnesses or who have disabilities and need health and long-term care services, such as home care or adult day care, to enable them to stay in their homes and communities as long as possible. Our Medicaid operations in certain states individually account for 10% or more of our consolidated premium revenue. Those states and the respective Medicaid premium revenue as a percentage of total consolidated premium revenue are as follows: For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 Kentucky 15% 15% 15% 16% Florida 13% 15% 13% 15% Georgia * 10% * 10% *Effective July 1, 2017, we began services under a new Medicaid contract with the State of Georgia serving TANF and CHIP beneficiaries. Due to the addition of a fourth managed care organization to the state program, our Georgia Medicaid membership declined by approximately 62,000 members as of June 30, 2018 , compared with June 30, 2017 . As a result of the decline in membership, premium revenue attributable to our Georgia Medicaid health plan accounted for less than 10% of our consolidated premium revenue for the three and six months ended June 30, 2018 . In July 2018, we received a Notice of Intent to Award a contract from the Florida Department of Health to provide statewide-managed care services to more than 60,000 children with medically complex conditions through the Children's Medical Services Managed Care Plan ("CMS Plan"). Under the proposed five -year contract award expected to begin on January 1, 2019, our Florida subsidiary, Staywell, will be the sole contractor for the CMS Plan. Additionally, in April 2018, we received a Notice of Agency Decision from the Florida Agency for Health Care Administration (“AHCA”) that it intends to award our subsidiary, Staywell, a new five -year contract to provide managed care services to Medicaid-eligible beneficiaries, including Managed Medical Assistance and Long-Term Care beneficiaries in 10 of 11 regions. As part of the Medicaid Managed Care program, we expect to provide statewide managed care services to beneficiaries in the Serious Mental Illness Specialty Plan, which currently has more than 75,000 beneficiaries statewide. The new statewide Medicaid Managed Care program is expected to begin no earlier than October 1, 2018. These contract awards are subject to the outcome of a protest and appeal process. Medicare Health Plans Medicare is a federal program that provides eligible persons age 65 and over and some disabled persons with a variety of hospital, medical and prescription drug benefits. MA is Medicare's managed care alternative to the original Medicare program, which provides individuals standard Medicare benefits directly through CMS. Our MA CCPs generally require members to seek health care services and select a primary care physician from a network of health care providers. In addition, we offer coverage of prescription drug benefits under the Medicare Part D program as a component of most of our MA plans. Medicare PDPs We offer stand-alone Medicare Part D coverage to Medicare-eligible beneficiaries in our Medicare PDPs segment. The Medicare Part D prescription drug benefit is supported by risk sharing with the federal government through risk corridors designed to limit the losses and gains of the participating drug plans and by reinsurance for catastrophic drug costs. The government subsidy is based on the national weighted average monthly bid for this coverage, adjusted for risk factor payments. Additional subsidies are provided for dually-eligible beneficiaries and specified low-income beneficiaries. The Part D program offers national in-network prescription drug coverage that is subject to limitations in certain circumstances. Summary of Financial Information Reportable operating segments are defined as components of an enterprise for which discrete financial information is available and evaluated on a regular basis by the enterprise's decision-makers to determine how resources should be allocated to an individual segment and to assess performance of those segments. Accordingly, we have three reportable segments: Medicaid Health Plans, Medicare Health Plans and Medicare PDPs. A summary of financial information for our reportable segments through the gross margin level and reconciliation to income from operations is presented in the table below. For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 (in millions) Premium revenue: Medicaid Health Plans $ 2,866.2 $ 2,751.4 $ 5,676.1 $ 5,335.6 Medicare Health Plans 1,546.4 1,316.6 3,102.9 2,411.3 Medicare PDPs 200.0 225.6 459.9 493.7 Total premium revenue 4,612.6 4,293.6 9,238.9 8,240.6 Medical benefits expense: Medicaid Health Plans 2,438.6 2,386.9 4,863.0 4,697.5 Medicare Health Plans 1,281.9 1,136.9 2,589.0 2,045.1 Medicare PDPs 145.5 195.2 376.0 455.0 Total medical benefits expense 3,866.0 3,719.0 7,828.0 7,197.6 ACA industry fee expense: Medicaid Health Plans 47.8 — 97.1 — Medicare Health Plans 26.7 — 54.3 — Medicare PDPs 4.5 — 9.1 — Total ACA industry fee expense 79.0 — 160.5 — Gross margin Medicaid Health Plans 379.8 364.5 716.0 638.1 Medicare Health Plans 237.8 179.7 459.6 366.2 Medicare PDPs 50.0 30.4 74.8 38.7 Total gross margin 667.6 574.6 1,250.4 1,043.0 Investment and other income 26.4 11.4 46.3 18.6 Other expenses (1) (460.1 ) (444.1 ) (901.6 ) (816.5 ) Income from operations $ 233.9 $ 141.9 $ 395.1 $ 245.1 (1) Other expenses include selling, general and administrative expenses, Medicaid premium taxes, depreciation and amortization and interest.

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE We compute basic earnings per common share on the basis of the weighted-average number of unrestricted common shares outstanding. We compute diluted earnings per common share on the basis of the weighted-average number of unrestricted common shares outstanding plus the dilutive effect of our stock-based compensation awards using the treasury stock method. The calculation of the weighted-average common shares outstanding — diluted is as follows: For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 Weighted-average common shares outstanding — basic 44,759,808 44,498,610 44,682,850 44,432,299 Dilutive effect of outstanding stock-based compensation awards 522,486 435,441 556,360 448,058 Weighted-average common shares outstanding — diluted 45,282,294 44,934,051 45,239,210 44,880,357 Anti-dilutive stock-based compensation awards excluded from computation 141,073 3,091 209,232 3,641

INVESTMENTS

INVESTMENTS	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS The Company considers all of its investments as available-for-sale securities. Excluding restricted cash, cash equivalents and investments, the amortized cost, gross unrealized gains or losses and estimated fair value of short-term and long-term investments by security type are summarized in the following tables. Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2018 Asset-backed securities $ 87.5 $ — $ (0.7 ) $ 86.8 Corporate debt securities 680.6 0.2 (9.5 ) 671.3 Municipal securities 211.0 0.3 (1.9 ) 209.4 Residential mortgage-backed securities 7.8 — (0.2 ) 7.6 Short-term time deposits 369.2 — — 369.2 Government and agency obligations 105.0 — (1.5 ) 103.5 Other securities 67.7 — — 67.7 Total $ 1,528.8 $ 0.5 $ (13.8 ) $ 1,515.5 December 31, 2017 Asset-backed securities $ 88.9 $ — $ (0.2 ) $ 88.7 Corporate debt securities 400.6 0.7 (1.2 ) 400.1 Municipal securities 223.7 1.0 (1.9 ) 222.8 Residential mortgage-backed securities 11.2 — — 11.2 Short-term time deposits 300.4 — — 300.4 Government and agency obligations 148.7 — (1.2 ) 147.5 Other securities 65.2 — (0.2 ) 65.0 Total $ 1,238.7 $ 1.7 $ (4.7 ) $ 1,235.7 Contractual maturities of available-for-sale securities at June 30, 2018 are as follows: Total Within 1 Year 1 Through 5 Years 5 Through 10 Years Thereafter Asset-backed securities $ 86.8 $ 21.8 $ 60.8 $ 1.3 $ 2.9 Corporate debt securities 671.3 312.2 272.8 78.0 8.3 Municipal securities 209.4 10.7 128.2 70.0 0.5 Residential mortgage-backed securities 7.6 — — — 7.6 Short-term time deposits 369.2 369.2 — — — Government and agency obligations 103.5 26.8 74.8 1.9 — Other securities 67.7 52.8 — 3.1 11.8 Total $ 1,515.5 $ 793.5 $ 536.6 $ 154.3 $ 31.1 Actual maturities may differ from contractual maturities due to the exercise of pre-payment options. We sold available-for-sale investments totaling $138.6 million and $74.7 million during the three months ended June 30, 2018 and 2017, respectively, and $218.8 million and $82.9 million during the six months ended June 30, 2018 and 2017, respectively. Gross realized losses resulting from sales and redemptions of our available-for-sale investments were $1.7 million and $2.9 million for the three and six months ended June 30, 2018, respectively, while gross realized gains were immaterial for these periods. Realized gains and losses resulting from sales and redemptions of our available-for-sale investments were not material for the three and six months ended June 30, 2017. Additionally, we did not realize any other-than-temporary impairment during any of these periods.

RESTRICTED CASH, CASH EQUIVALEN

RESTRICTED CASH, CASH EQUIVALENTS AND INVESTMENTS	6 Months Ended
	Jun. 30, 2018
Restricted Investments Note [Abstract]
RESTRICTED CASH, CASH EQUIVALENTS AND INVESTMENTS	RESTRICTED CASH, CASH EQUIVALENTS AND INVESTMENTS As a condition for licensure, we are required to maintain certain funds on deposit or pledged to various state agencies. Certain of our state contracts require the issuance of surety bonds. We classify restricted cash, cash equivalents and investments as long-term regardless of the contractual maturity date of the securities held, due to the nature of the states' requirements. The amortized cost, gross unrealized gains, gross unrealized losses and fair value of our restricted cash, cash equivalents and investment securities are as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2018 Cash $ 3.1 $ — $ — $ 3.1 Money market funds 57.8 — — 57.8 U.S. government securities and other 169.2 — (0.8 ) 168.4 Total $ 230.1 $ — $ (0.8 ) $ 229.3 December 31, 2017 Cash $ 5.7 $ — $ — $ 5.7 Money market funds 58.7 — — 58.7 U.S. government securities and other 147.4 — (0.8 ) 146.6 Total $ 211.8 $ — $ (0.8 ) $ 211.0 Realized gains and losses on sales and redemptions of our restricted cash, cash equivalents and investments were not material for the three and six months ended June 30, 2018 and 2017.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION Our Compensation Committee awards certain equity-based compensation under our stock plans, including restricted stock units ("RSUs"), performance stock units ("PSUs") and, through 2015, market stock units ("MSUs"). Compensation expense related to our stock-based compensation awards was $18.0 million and $13.9 million for the three months ended June 30, 2018 and 2017, respectively, and $30.1 million and $23.5 million for the six months ended June 30, 2018 and 2017, respectively. As of June 30, 2018 , there was $95.3 million of unrecognized compensation cost related to unvested stock-based compensation arrangements that is expected to be recognized over a weighted-average period of 2.0 years . The unrecognized compensation cost for certain of our PSUs, which are subject to variable accounting, was determined based on our closing common stock price of $246.24 as of June 29, 2018 and amounted to approximately $29.9 million of the total unrecognized compensation cost. Due to the nature of the accounting for these awards, future compensation cost will fluctuate based on changes in our common stock price. A summary of RSU, PSU and MSU award activity, at target, for the six months ended June 30, 2018 , is presented in the table below. For our PSUs and MSUs, shares attained over target upon vesting are reflected as awards granted during the period, while shares canceled due to vesting below target are reflected as awards forfeited during the period. RSUs PSUs MSUs Total Outstanding as of January 1, 2018 274,643 552,618 45,230 872,491 Granted 114,105 255,042 45,075 414,222 Vested (110,607 ) (145,359 ) (90,150 ) (346,116 ) Forfeited (8,097 ) (14,984 ) (155 ) (23,236 ) Outstanding as of June 30, 2018 270,044 647,317 — 917,361 The weighted-average grant-date fair value of all equity awards granted during the six months ended June 30, 2018 was $199.72 . Refer to Note 2 - Summary of Significant Accounting Policies and Note 15 - Stock-based Compensation to the Consolidated Financial Statements included in our 2017 Form 10-K for additional information regarding our equity-compensation awards and related compensation cost measurement.

DEBT

DEBT	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
DEBT	DEBT The following table summarizes our outstanding debt obligations and their classification in the accompanying condensed consolidated balance sheets (in millions): June 30, 2018 December 31, 2017 Long-term debt, net: 5.25% Senior Notes, due April 1, 2025 $ 1,200.0 $ 1,200.0 Revolving Credit Facility — — Debt issuance costs (16.2 ) (17.6 ) Total long-term debt, net $ 1,183.8 $ 1,182.4 5.25% Senior Notes due 2025 On March 22, 2017, we completed the offering and sale of 5.25% unsecured senior notes due 2025 in the aggregate principal amount of $1,200.0 million (the “2025 Notes”). The aggregate net proceeds from the issuance of the 2025 Notes were $1,182.2 million , with a portion of the net proceeds from the offering being used to repay the $100.0 million outstanding under our credit agreement dated January 8, 2016 (the "Credit Agreement", discussed further below) and to redeem the full $900.0 million aggregate principal amount of our 5.75% unsecured senior notes (the "2020 Notes") on April 7, 2017 , which is discussed further below. The remaining net proceeds from the offering of the 2025 Notes are being used for general corporate purposes, including organic growth and working capital. The 2025 Notes are classified as long-term debt in our condensed consolidated balance sheet at June 30, 2018, based on their April 2025 maturity date. Refer to Note 10 - Debt to the consolidated financial statements included in our 2017 Form 10-K for additional information regarding these 2025 Notes, including applicable covenants. 5.75% Senior Notes due 2020 In November 2013, we issued $600.0 million in aggregate principal amount of our 2020 Notes. In June 2015, we issued an additional $300.0 million aggregate principal amount of our 2020 Notes pursuant to a reopening of our existing series of such notes. The offering was completed at an issue price of 104.50% , plus accrued interest. On April 7, 2017, we redeemed the full $900.0 million in aggregate principal amount outstanding of our 2020 Notes at a redemption price of 102.875% of the principal amount, plus accrued and unpaid interest. Our obligations under the related base indenture and supplemental indenture, each dated as of November 14, 2013, by and among us and The Bank of New York Trust Company, N.A., as trustee, were satisfied and discharged on April 7, 2017. In connection with the redemption of the 2020 Notes, we incurred a one-time loss on extinguishment of debt related to the redemption premium, the write-off of associated deferred financing costs and the write-off of the unamortized portion of associated premiums paid on the 2020 Notes. The loss on extinguishment of debt was reflected in our consolidated statements of comprehensive income upon redemption. Credit Agreement In January 2016, we entered into the Credit Agreement, which provides for a senior unsecured revolving loan facility (the "Revolving Credit Facility"), which had an initial aggregate principal amount at any time outstanding not to exceed $850.0 million . On March 22, 2017, we increased the aggregate principal amount available under our Credit Agreement from $850.0 million to $1.0 billion . Additionally, in March 2017, we repaid the $100.0 million outstanding under our Revolving Credit Facility, and as a result, there were no borrowings outstanding under the Revolving Credit Facility as of June 30, 2018 . Refer to Note 10 - Debt to the consolidated financial statements included in our 2017 Form 10-K for additional information regarding the Credit Agreement, including applicable covenants. See Note 14 - Subsequent Events for information regarding the terms of the Amended and Restated Credit Agreement (as defined herein), which was entered into on July 23, 2018. As of June 30, 2018 , and the date of this filing, we were in compliance with all covenants under the 2025 Notes and the Credit Agreement.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Our condensed consolidated balance sheets include the following financial instruments: cash and cash equivalents, investments, receivables, accounts payable, medical benefits payable, long-term debt, including any current portion of long-term debt, and other liabilities. We consider the carrying amounts of cash and cash equivalents, receivables, other current assets and current liabilities to approximate their fair value due to the short period of time between the origination of these instruments and the expected realization or payment. Certain assets and liabilities are measured at fair value on a recurring basis and are disclosed below. These assets and liabilities are classified into one of three levels of a hierarchy defined by GAAP. For a description of the methods and assumptions that are used to estimate the fair value and determine the fair value hierarchy classification of each class of financial instrument, see the consolidated financial statements and notes thereto included in our 2017 Form 10-K. Recurring Fair Value Measurements Assets and liabilities measured at fair value on a recurring basis at June 30, 2018 are as follows: Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments: Asset-backed securities $ 86.8 $ — $ 86.8 $ — Corporate debt securities 671.3 — 671.3 — Municipal securities 209.4 — 209.4 — Residential mortgage-backed securities 7.6 — 7.6 — Short-term time deposits 369.2 — 369.2 — Government and agency obligations 103.5 103.5 — — Other securities 67.7 52.8 14.9 — Total investments $ 1,515.5 $ 156.3 $ 1,359.2 $ — Restricted cash, cash equivalents and investments: Cash $ 3.1 $ 3.1 $ — $ — Money market funds 57.8 57.8 — — U.S. government securities and other 168.4 168.2 0.2 — Total restricted cash, cash equivalents and investments $ 229.3 $ 229.1 $ 0.2 $ — Assets and liabilities measured at fair value on a recurring basis at December 31, 2017 are as follows: Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments: Asset-backed securities $ 88.7 $ — $ 88.7 $ — Corporate debt securities 400.1 — 400.1 — Municipal securities 222.8 — 210.5 12.3 Residential mortgage-backed securities 11.2 — 11.2 — Short-term time deposits 300.4 — 300.4 — Government and agency obligations 147.5 147.5 — — Other securities 65.0 52.8 12.2 — Total Investments $ 1,235.7 $ 200.3 $ 1,023.1 $ 12.3 Restricted cash, cash equivalents and investments: Cash $ 5.7 $ 5.7 $ — $ — Money market funds 58.7 58.7 — — U.S. government securities and other 146.6 146.4 0.2 — Total restricted cash, cash equivalents and investments $ 211.0 $ 210.8 $ 0.2 $ — The following table presents the carrying value and fair value of our long-term debt outstanding as of June 30, 2018 and December 31, 2017 : Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Long-term debt - June 30, 2018 $ 1,183.8 $ 1,197.1 $ — $ — Long-term debt - December 31, 2017 1,182.4 1,274.3 — — The fair value of our 2025 Notes were determined based on quoted market prices; therefore, would be classified within Level 1 of the fair value hierarchy. There were no borrowings outstanding under our Revolving Credit Facility as of June 30, 2018 or December 31, 2017. The following table presents the changes in the fair value of our Level 3 auction rate securities for the three and six months ended June 30, 2018 and 2017. For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 Balance at beginning of period $ 12.3 $ 12.4 $ 12.3 $ 12.4 Realized gains (losses) in earnings (1.2 ) — (1.2 ) — Changes in unrealized gains (losses) in other comprehensive income 1.4 — 1.4 Purchases, sales and redemptions (12.5 ) (0.1 ) (12.5 ) (0.1 ) Net transfers in or (out) of Level 3 — — — — Balance at end of period $ — $ 12.3 $ — $ 12.3 During the three months ended June 30, 2018, we sold the remaining auction rate securities in our portfolio. The sale resulted in a loss of $1.2 million that was included within investment and other income in the condensed consolidated statements of comprehensive income.

MEDICAL BENEFITS PAYABLE

MEDICAL BENEFITS PAYABLE	6 Months Ended
	Jun. 30, 2018
MEDICAL BENEFITS PAYABLE [Abstract]
MEDICAL BENEFITS PAYABLE	MEDICAL BENEFITS PAYABLE A reconciliation of the beginning and ending balances of medical benefits payable, by segment, is as follows: Medicaid Health Plans Medicare Health Plans Medicare PDPs Consolidated For the six months ended June 30, 2018 2017 2018 2017 2018 2017 2018 2017 Beginning balance (1) $ 1,373.2 $ 1,135.8 $ 722.5 $ 510.0 $ 50.6 $ 44.7 $ 2,146.3 $ 1,690.5 Acquisitions — — — 128.1 — — — 128.1 Medical benefits incurred related to: Current year 5,029.5 4,866.4 2,709.5 2,133.2 445.1 517.7 8,184.1 7,517.3 Prior years (166.5 ) (168.9 ) (120.5 ) (88.1 ) (69.1 ) (62.7 ) (356.1 ) (319.7 ) Total 4,863.0 4,697.5 2,589.0 2,045.1 376.0 455.0 7,828.0 7,197.6 Medical benefits paid related to: Current year (3,906.0 ) (3,838.2 ) (2,065.8 ) (1,682.7 ) (414.3 ) (483.7 ) (6,386.1 ) (6,004.6 ) Prior years (834.4 ) (725.6 ) (438.1 ) (300.7 ) 29.7 19.1 (1,242.8 ) (1,007.2 ) Total (4,740.4 ) (4,563.8 ) (2,503.9 ) (1,983.4 ) (384.6 ) (464.6 ) (7,628.9 ) (7,011.8 ) Ending balance (1) $ 1,495.8 $ 1,269.5 $ 807.6 $ 699.8 $ 42.0 $ 35.1 $ 2,345.4 $ 2,004.4 (1) The Medicaid Health Plans and Consolidated beginning and ending balances for 2018 include a premium deficiency reserve for our Illinois Medicaid program ("Illinois PDR"), which amounted to $37.9 million and $45.6 million at June 30, 2018 and December 31, 2017, respectively. See Note 2 - Summary of Significant Accounting Policies in our 2017 Form 10-K for further discussion. We recognize the cost of medical benefits in the period in which services are provided, including an estimate of the cost of medical benefits incurred but not reported ("IBNR"). Medical benefits expense includes direct medical expenses and certain medically-related administrative costs. We evaluate our estimates of medical benefits payable as we obtain more complete claims information and medical expense trend data over time. We record differences between actual experience and estimates used to establish the liability, which we refer to as favorable and unfavorable prior year reserve developments, as increases or decreases to medical benefits expense in the period we identify the differences. Our consolidated medical benefits payable developed favorably by approximately $356.1 million and $319.7 million for the six months ended June 30, 2018 and 2017, respectively. The release of the provision for moderately adverse conditions included in our prior year estimates was substantially offset by the provision for moderately adverse conditions established for claims incurred in the current year. Accordingly, the favorable development in our estimate of medical benefits payable related to claims incurred in prior years does not directly correspond to a decrease in medical benefits expense recognized during the period in which the favorable development is recognized. Excluding the prior year development related to the release of the provision for moderately adverse conditions, our estimates of consolidated medical benefits payable developed favorably by approximately $173.4 million and $178.8 million for the six months ended June 30, 2018 and 2017 , respectively. Such amounts are net of the development relating to refunds due to government customers with minimum loss ratio provisions. The net favorable development recognized in both 2018 and 2017 was primarily in our Medicaid Health Plans segment and, to the lesser extent, in our Medicare Health Plans segment. The net favorable development resulted primarily due to a number of operational and clinical initiatives planned and executed, throughout both 2016 and 2017, that contributed to lower than expected pharmacy and medical trends, and actual claim submission time being faster than we originally assumed (i.e., our completion factors were higher than we originally assumed) in establishing our medical benefits payable in the prior years. This development does not directly correspond to an increase in our current year operating results as these reductions were offset by estimated current period medical benefits expense when we established our estimate of the current year medical benefits payable. Both completion factor and medical trend assumptions are influenced by utilization levels, unit costs, mix of business, provider reimbursement levels, processing system conversions and changes, claim inventory levels, claim processing patterns, our ability and practices to manage medical and pharmaceutical costs, claim submission patterns and operational changes resulting from business combinations, among others. Our actual costs were ultimately less than expected. Our Universal American acquisition in April 2017 resulted in an increase to medical benefits payable as of the Effective Date. See Note 2- Acquisitions , for additional information on the Universal American acquisition.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Our effective income tax rate on pre-tax income was 34.1% and 34.8% for the three and six months ended June 30, 2018 , respectively, compared with 35.4% and 35.1% fo r the three and six months ended June 30, 2017 , respectively. The decline in our effective rate was primarily driven by the federal income tax rate decrease resulting from the enactment of the Tax Cuts and Jobs Act of 2017 (“TCJA”) (discussed in Note 14 - Income Taxes to the consolidated financial statements in the 2017 Form 10-K). This decrease was partially offset by the expiration of the 2017 ACA industry fee moratorium and reestablishment of the ACA industry fee for 2018, which is nondeductible for tax purposes. There were no significant changes to unrecognized tax benefits for the three and six months ended June 30, 2018. Our unrecognized tax benefits are not expected to change significantly during the next 12 months. The TCJA was enacted on December 22, 2017. The TCJA, in part, reduced the U.S. federal statutory corporate income tax rate from 35% to 21% effective January 1, 2018. Staff Accounting Bulletin No. 118 allows filers one year subsequent to the end of the tax year to finalize the valuation of deferred tax assets and liabilities. At June 30, 2018, we had not completed our accounting for the tax effects resulting from enactment of TCJA with respect to valuation of our deferred tax assets and liabilities. However, our income taxes for the three months ended June 30, 2018 include $1.3 million of discrete tax benefit associated primarily with deferred tax assets acquired in the Universal American transaction. We will continue to make and refine our calculations as additional analysis is completed.

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	6 Months Ended
	Jun. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	DISCONTINUED OPERATIONS On August 3, 2016, our subsidiary, Universal American, completed the sale of its Traditional Insurance business prior to our acquisition of Universal American. This was accomplished by selling two life insurance subsidiaries, while retaining ownership of a third life insurance subsidiary, American Progressive Life & Health Insurance of New York ("Progressive"). The sale of the Traditional Insurance business underwritten by Progressive was accomplished through a 100% quota-share reinsurance treaty with a wholly-owned subsidiary of Nassau Re, that, when considered in combination with other reinsurance transactions previously entered into, resulted in the reinsurance of all of the Traditional Insurance policies that were underwritten by Progressive. Accordingly, the discontinued Traditional Insurance business did not materially affect our condensed consolidated statements of comprehensive income for any of the periods presented. In accordance with ASC 360-10, Property, Plant and Equipment and ASC 205-20, Presentation of Financial Statements—Discontinued Operations , the Traditional Insurance business has been reported in discontinued operations in this Form 10-Q. The following table summarizes the total assets and liabilities of our discontinued operations: June 30, 2018 December 31, 2017 (in millions) Assets Cash and cash equivalents $ 0.4 $ 1.3 Investments 44.4 46.5 Reinsurance recoverables 167.8 166.9 Other assets 0.5 0.5 Total Assets $ 213.1 $ 215.2 Liabilities Reserves and other policy liabilities $ 150.3 $ 148.6 Other liabilities 62.8 66.6 Total liabilities 213.1 215.2 Progressive's traditional insurance products are reinsured under quota share coinsurance treaties with unaffiliated insurers, while the life insurance risks are reinsured under either quota share coinsurance or yearly-renewable term treaties with unaffiliated insurers. Under quota share coinsurance treaties, we pay the reinsurer an agreed upon percentage of all premiums and the reinsurer reimburses us that same percentage of any losses. In addition, the reinsurer pays us certain allowances to cover commissions, the cost of administering the policies and premium taxes. Under yearly-renewable term treaties, the reinsurer receives premiums at an agreed upon rate for its share of the risk on a yearly-renewable term basis. We also use excess of loss reinsurance agreements for certain policies whereby we limit our loss in excess of specified thresholds. We evaluate the financial condition of our Traditional Insurance reinsurers and monitor concentrations of credit risk to minimize our exposure to significant losses from reinsurer insolvencies. We are obligated to pay claims in the event that a reinsurer to whom we have ceded an insured claim fails to meet its obligations under the reinsurance agreement. We are not aware of any instances where any of our reinsurers have been unable to pay any policy claims on any reinsured business.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Indemnification Obligations Under Delaware law, our charter and bylaws and certain indemnification agreements to which we are a party, we are obligated to indemnify, or we have otherwise agreed to indemnify, certain of our current and former directors, officers and associates with respect to current and future investigations and litigation, including the matters discussed in this note. The indemnification agreements for our directors and executive officers with respect to events occurring prior to May 2009 require us to indemnify an indemnitee to the fullest extent permitted by law if the indemnitee was or is or becomes a party to or a witness or other participant in any proceeding by reason of any event or occurrence related to the indemnitee's status as a director, officer, associate, agent or fiduciary of the Company or any of our subsidiaries. The indemnification agreements require us to indemnify an indemnitee against all expenses, including attorney's fees, judgments, fines, settlement amounts and interest and other charges, and any taxes as a result of the receipt of payments under the indemnification agreement. We will not indemnify the indemnitee if not permitted under applicable law. We are required to advance all expenses incurred by the indemnitee. We are entitled to reimbursement by an indemnitee of expenses advanced if the indemnitee is not permitted to be reimbursed under applicable law after a final judicial determination is made and all rights of appeal have been exhausted or lapsed. We amended and restated our indemnification agreements in May 2009. The revised agreements apply to our officers and directors with respect to events occurring after that time. Pursuant to the 2009 indemnification agreements, we will indemnify the indemnitee against all expenses, including attorney's fees, judgments, penalties, fines, settlement amounts and any taxes imposed as a result of payments made under the indemnification agreement incurred in connection with any proceedings that relate to the indemnitee's status as a director, officer or associate of the Company or any of our subsidiaries or any other enterprise that the indemnitee was serving at our request. We will also indemnify for expenses incurred by an indemnitee if the indemnitee, by reason of his or her corporate status, is a witness in any proceeding. Further, we are required to indemnify for expenses incurred by an indemnitee in defense of a proceeding to the extent the indemnitee has been successful on the merits or otherwise. Finally, if the indemnitee is involved in certain proceedings as a result of the indemnitee's corporate status, we are required to advance the indemnitee's reasonable expenses incurred in connection with such proceeding, subject to the requirement that the indemnitee repay the expenses if it is ultimately determined that the indemnitee is not entitled to be indemnified. We are not obligated to indemnify an indemnitee for losses incurred in connection with any proceeding if a determination has not been made by the Board of Directors, a committee of disinterested directors or independent legal counsel in the specific case that the indemnitee has satisfied any standards of conduct required as a condition to indemnification under Section 145 of the Delaware General Corporation Law. Pursuant to our obligations, we have advanced legal fees and related expenses to three former officers and two additional associates who were criminally indicted in connection with the government investigations of the Company that commenced in 2007 related to federal criminal health care fraud charges including conspiracy to defraud the United States, false statements relating to health care matters, and health care fraud in connection with their defense of criminal charges. In June 2013, the jury in the federal criminal trial reached guilty verdicts on multiple charges for the four individuals that were tried in 2013. In May 2014, the individuals were sentenced and our request for restitution was denied. All four individuals filed notices of appeal and the government filed notices of cross appeal on three of the four individuals, which the government has subsequently voluntarily dismissed. The appellate court affirmed the convictions in August 2016. Mr. Farha filed a petition for a writ of certiorari to the United States Supreme Court in January 2017. In April 2017, the United States Supreme Court declined to hear the appeal by Mr. Farha. The fifth individual, Mr. Bereday, entered a guilty plea in June 2017 in connection with the federal criminal charges, which was accepted by the court in July 2017. Mr. Bereday was sentenced in November 2017. We have also previously advanced legal fees and related expenses to these five individuals regarding: a dispute in Delaware Chancery Court related to whether we were legally obligated to advance fees or indemnify certain of these individuals; the class actions titled Eastwood Enterprises, L.L.C. v. Farha, et al . and Hutton v. WellCare Health Plans, Inc. et al . filed in federal court; six stockholder derivative actions filed in federal and state courts between October 2007 and January 2008; an investigation by the United States Securities & Exchange Commission (the "Commission"); an action by the Commission filed in January 2012 against three of the five individuals, Messrs. Farha, Behrens and Bereday, and a qui tam action against Messrs. Farha, Behrens and Bereday in federal court. We settled the class actions in May 2011. In 2010, we settled the stockholder derivative actions and we were realigned as the plaintiff to pursue our claims against Messrs. Farha, Behrens and Bereday. Pursuant to the settlement agreements described below, Messrs. Farha, Behrens and Bereday were dismissed from the federal court and state derivative actions. Pursuant to the settlement agreement with Mr. Bereday described below, Mr. Bereday was dismissed from the fee advancement case in Delaware Chancery Court. The Commission action was closed in May 2018. The qui tam action is currently stayed and the stay is subject to being lifted at any time. In April 2017, the Commission and Mr. Farha entered into a consent judgment to pay $12.5 million to the Commission and $7.5 million to us. In April 2017, the Commission and Mr. Behrens also entered into a consent judgment to pay $4.5 million to the Commission and $1.5 million to us. In May 2018, the Commission and Mr. Bereday entered into a consent judgment to pay $4.5 million to the Commission and the case was closed. In addition, we have advanced a portion of the legal fees and related expenses to Mr. Farha in connection with lawsuits he filed in Delaware and Florida state court to have certain restrictions lifted on WellCare stock purportedly awarded to him during his employment with us. The Delaware and Florida state court matters have been dismissed. In September 2016, we entered into a settlement agreement with Mr. Farha pursuant to which he paid us $7.5 million , as referenced in the April 2017 consent judgment with the Commission, and we agreed that we would not seek to recover additional legal fees previously advanced related to these matters, and that our obligation to continue advancing fees would be limited to no more than an additional $7.5 million . We also have advanced a portion of the legal fees and related expenses to Mr. Behrens in connection with his lawsuit in Delaware state court to have certain restrictions lifted on WellCare stock purportedly awarded to him during his employment with WellCare, which the court dismissed. In October 2016, we also entered into a settlement agreement with Mr. Behrens pursuant to which he paid us $1.5 million , as referenced in the April 2017 consent judgment with the Commission, and we agreed that we would not seek to recover additional legal fees previously advanced in connection with these matters, and that our obligation to continue advancing fees would be limited to no more than an additional $1.5 million . In June 2017, we entered into a settlement agreement with Mr. Bereday that became effective in July 2017, pursuant to which we agreed that we would not seek to recover legal fees previously advanced in connection with these matters, and that our obligation to continue advancing fees would be limited to no more than an additional $2.5 million . In connection with these matters, we have advanced to the five individuals cumulative legal fees and related expenses of approximately $236.9 million from the inception of the investigations through June 30, 2018 . We incurred $0.2 million and $0.7 million of these fees and related expenses during the three and six months ended June 30, 2018, respectively, compared with $3.0 million and $5.5 million , respectively, for the same periods in and 2017. These fees are not inclusive of the amounts recovered from Mr. Farha and Mr. Behrens discussed above. We expense these costs as incurred and classify the costs as selling, general and administrative expense incurred in connection with the investigations and related matters. We have exhausted our insurance policies related to reimbursement of our advancement of fees related to these matters. We are unable to estimate the total amount of these costs or a range of possible loss. Accordingly, we continue to expense these costs as incurred. Other Lawsuits and Claims Based on the nature of our business, we are subject to regulatory reviews or other investigations by various state insurance and health care regulatory authorities and other state and federal regulatory authorities. These authorities regularly scrutinize the business practices of health insurance and benefits companies and their reviews focus on numerous facets of our business, including claims payment practices, provider contracting, competitive practices, commission payments, privacy issues and utilization management practices, among others. Some of these reviews have historically resulted in fines imposed on us and some have required changes to our business practices. We continue to be subject to such reviews, which may result in additional fines and/or sanctions being imposed, premium refunds or additional changes in our business practices. Separate and apart from the legal matters described above, we are also involved in other legal actions in the normal course of our business, including, without limitation, protests and appeals related to Medicaid procurement awards, wage and hour claims and other employment claims, claims for indemnification under purchase agreements, vendor disputes and provider disputes regarding payment of claims. Some of these actions seek monetary damages including claims for liquidated or punitive damages, which are not covered by insurance. We review relevant information with respect to these litigation matters and we update our estimates of reasonably possible losses and related disclosures. We accrue an estimate for contingent liabilities, including attorney's fees related to these matters, if a loss is probable and estimable. Currently, we do not expect that the resolution of any of these currently pending actions, either individually or in the aggregate, will differ materially from our current estimates or have a material adverse effect on our results of operations, financial condition and cash flows. However, the outcome of any legal actions cannot be predicted, and therefore actual results may differ from those estimates.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS We have evaluated subsequent events through the date these financial statements were issued. We determined there were no events, other than described below, that required disclosure or recognition in these financial statements. Amended and Restated Credit Agreement On July 23, 2018, we entered into an amended and restated Credit Agreement (the “Amended and Restated Credit Agreement”) with JPMorgan Chase Bank, N.A., as administrative agent, and the other lenders party thereto. The Amended and Restated Credit Agreement, among other things, modified the terms of the Credit Agreement to (i) increase the total commitment under the Revolving Credit Facility from $1.0 billion to $1.3 billion , (ii) extend the maturity date of loans made under the Revolving Credit Facility from January 2021 to July 2023 and (iii) decrease the applicable margins for borrowings under the Revolving Credit Facility to a range of (A) 0.375% to 1.00% per annum for ABR Loans (as defined in the Amended and Restated Credit Agreement) and (B) 1.375% to 2.00% per annum for Eurodollar Loans (as defined in the Amended and Restated Credit Agreement), in each case depending on our ratio of total debt to consolidated earnings before interest, taxes, depreciation and amortization ("EBITDA"), as calculated in accordance with the Amended and Restated Credit Agreement. The Amended and Restated Credit Agreement also includes an accordion feature which allows us to increase the total commitments under the Revolving Credit Facility by up to an additional $500.0 million , subject to certain conditions. Unutilized commitments under the Amended and Restated Credit Agreement are subject to a fee of 0.20% to 0.30% depending upon our ratio of total debt to consolidated EBITDA, as calculated in accordance with the Amended and Restated Credit Agreement. The Amended and Restated Credit Agreement includes negative and financial covenants that limit certain of our activities, including (i) restrictions on our ability to incur additional indebtedness; and (ii) financial covenants that require (a) the ratio of total debt to consolidated EBITDA not to exceed a maximum and (b) a minimum interest expense and principal payment coverage ratio. The Amended and Restated Credit Agreement also contains customary representations and warranties that must be accurate in order for us to borrow under the Revolving Credit Facility. In addition, the Amended and Restated Credit Agreement contains customary events of default. If an event of default occurs and is continuing, we may be required immediately to repay all amounts outstanding under the Amended and Restated Credit Agreement. Lenders holding greater than 50% of the loans and commitments under the Amended and Restated Credit Agreement may elect to accelerate the maturity of the loans. We expect to use the proceeds of the Revolving Credit Facility for general corporate purposes, including the pending acquisition of Meridian. As of July 31, 2018, no borrowings were outstanding under the Amended and Restated Credit Agreement.

ORGANIZATION, BASIS OF PRESEN21

ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated balance sheets and statement of comprehensive income, changes in stockholder's equity, and cash flows include our accounts and the accounts of our subsidiaries over which we have control or are the primary beneficiary. We eliminated all intercompany accounts and transactions. The accompanying unaudited condensed consolidated interim financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP"). Accordingly, certain financial information and footnote disclosures normally included in financial statements prepared in accordance with GAAP, but that are not required for interim reporting purposes, have been condensed or omitted. The accompanying unaudited condensed consolidated interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto, for the fiscal year ended December 31, 2017 , included in our Annual Report on Form 10-K ("2017 Form 10-K"), which was filed with the U.S. Securities and Exchange Commission ("SEC") in February 2018. Results for the interim periods presented are not necessarily indicative of results that may be expected for the entire year or any other interim period. In the opinion of management, the interim financial statements reflect all normal recurring adjustments that we consider necessary for the fair presentation of our financial position, results of operations and cash flows for the interim periods presented. In accordance with GAAP, we make certain estimates and assumptions that affect the amounts reported in the condensed consolidated interim financial statements and accompanying notes. We base these estimates, including assumptions as to the annualized tax rate, on our knowledge of current events and anticipated future events and evaluate and update our assumptions and estimates on an ongoing basis; however, actual results may differ from our estimates. We evaluated all material events subsequent to the date of these condensed consolidated interim financial statements. Certain reclassifications were made to 2017 financial information to conform to the 2018 presentation.
Use of Estimates	In the opinion of management, the interim financial statements reflect all normal recurring adjustments that we consider necessary for the fair presentation of our financial position, results of operations and cash flows for the interim periods presented. In accordance with GAAP, we make certain estimates and assumptions that affect the amounts reported in the condensed consolidated interim financial statements and accompanying notes. We base these estimates, including assumptions as to the annualized tax rate, on our knowledge of current events and anticipated future events and evaluate and update our assumptions and estimates on an ongoing basis; however, actual results may differ from our estimates. We evaluated all material events subsequent to the date of these condensed consolidated interim financial statements.
Reclassifications	Certain reclassifications were made to 2017 financial information to conform to the 2018 presentation.
Premium Receivable and Unearned Premiums	We record premiums earned but not received as premiums receivable and record premiums received in advance of the period of service as unearned premiums in our condensed consolidated balance sheets.
Medicare Part D Settlements	We receive certain Part D prospective subsidy payments from the Centers for Medicare & Medicaid Services ("CMS") for our MA and PDP members as a fixed monthly per member amount, based on the estimated costs of providing prescription drug benefits over the plan year, as reflected in our bids. A discussion of the subsidy components under Part D is included in Note 2 - Summary of Significant Accounting Policies to the Consolidated Financial Statements included in our 2017 Form 10-K. CMS will fully reimburse these subsidies, or recoup overpaid subsidies made during the plan year, as part of its annual settlement process that typically occurs in the fourth quarter of the subsequent year and, accordingly, there is no insurance risk to us. Therefore, amounts received for these subsidies are not considered premium revenue, and are reported, net of the subsidy benefits paid, as Funds receivable (payable) for the benefit of members in the condensed consolidated balance sheets.
ACA Industry Fee	The ACA imposed certain new taxes and fees, including an annual premium-based health insurance industry assessment (the "ACA industry fee") on health insurers, which began in 2014. In December 2015, President Obama signed the Consolidated Appropriations Act, 2016 which, among other provisions, included a one-year moratorium on the ACA industry fee for 2017, which also eliminated the associated Medicaid ACA industry fee reimbursements from our state government partners for 2017.
Accounting Standards Recently Adopted and Pending Adoption	Recently Adopted Accounting Standards In May 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2017-09, " Compensation-Stock Compensation (Topic 718) - Scope of Modification Accounting ". This guidance addresses which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting pursuant to Topic 718. An entity should account for the effects of a modification unless (a) the fair value of the modified award is the same as the fair value of the original award, (b) the vesting conditions of the modified award are the same as the vesting conditions of the original award and (c) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments in this guidance should be applied prospectively for public business entities effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In January 2017, the FASB issued ASU 2017-04, " Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ". This update eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge. As a result, an entity should perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In January 2017, the FASB issued ASU 2017-01, “ Business Combinations (Topic 805): Clarifying the Definition of a Business ”. The amendments in this update provide guidance to assist entities with evaluating when a group of transferred assets and activities (collectively referred to as a "set") is a business. This new guidance provides for a "screen", which requires a determination that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. If the screen's threshold is not met, a set cannot be considered a business unless it includes an input and a substantive process that together significantly contribute to the ability to create output, eliminating the evaluation of whether a market participant could replace missing elements. This guidance is effective for prospective business combinations for public entities for interim and annual periods beginning after December 15, 2017. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In November 2016, the FASB issued ASU 2016-18, “ Statement of Cash Flows (Topic 230) Restricted Cash; a consensus of the FASB Emerging Issues Task Force ”. This update requires entities to reconcile, on the statement of cash flows, changes in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. We adopted this guidance retrospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 and 2017 , respectively. The following table provides a reconciliation of cash, cash equivalents and restricted cash and cash equivalents as reported within the condensed consolidated balance sheets to the total of the same such amounts shown within the condensed consolidated statements of cash flows: As of June 30, 2018 December 31, 2017 Cash and cash equivalents $ 5,098.5 $ 4,198.6 Restricted cash and cash equivalents (1) 60.9 64.4 Total cash, cash equivalents, and restricted cash and cash equivalents $ 5,159.4 $ 4,263.0 (1) Restricted cash and cash equivalents consist of restricted cash and restricted money market funds and are included in Restricted cash, cash equivalents and investments within noncurrent assets of our condensed consolidated balance sheets. Refer to Note 6 - Restricted Cash, Cash Equivalents and Investments for further detail. In August 2016, the FASB issued ASU 2016-15, " Statement of Cash Flows Classification of Certain Cash Receipts and Cash Payments (Topic 230) ". This update targets eight specific areas to clarify how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This guidance is effective for public entities for interim and annual periods beginning after December 15, 2017, with early adoption permitted. We adopted this guidance on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In January 2016, the FASB issued ASU 2016-01, " Financial Instrument - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, " which requires entities to measure equity securities that are not consolidated or accounted for under the equity method at fair value through net income. This amendment also simplifies the impairment test of equity investments without readily determinable fair values. In February 2018, the FASB issued ASU 2018-03, " Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, " which clarifies that an entity that uses the measurement alternative for equity securities without readily determinable fair values can change its measurement approach to fair value. This guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We adopted this guidance prospectively on January 1, 2018. The adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . In May 2014, the FASB issued ASU 2014-09, " Revenue from Contracts with Customers (Topic 606) ". ASU 2014-09 supersedes existing revenue recognition standards with a single model unless those contracts are within the scope of other standards (e.g., an insurance entity’s insurance contracts). The revenue recognition principle in ASU 2014-09 requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, new and enhanced disclosures are required. We adopted this guidance prospectively on January 1, 2018. Given that substantially all of our revenues are derived from insurance contracts accounted for in accordance with ASC 944, Financial Services-Insurance , which are specifically excluded from the scope of ASU 2014-09, the adoption of this guidance did not have a material effect on our consolidated results of operations, financial condition or cash flows for the three and six months ended June 30, 2018 . Accounting Standards Pending Adoption In February 2018, the FASB issued ASU 2018-02 " Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income", which allows entities to reclassify stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 from accumulated other comprehensive income to retained earnings. The guidance is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. We are currently assessing the effect this guidance will have on our consolidated results of operations, financial condition or cash flows. In March 2017, the FASB issued ASU 2017-08, " Receivables – Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities ". This update shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. Currently, entities generally amortize the premium as a yield adjustment over the contractual life of the security. The new guidance does not change the accounting for purchased callable debt securities held at a discount. This guidance is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. We are currently assessing the effect this guidance will have on our consolidated results of operations, financial condition or cash flows. In June 2016, the FASB issued ASU 2016-13, " Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, " which requires entities to use a current expected credit loss model, which is a new impairment model based on expected losses rather than incurred losses. Under this model, an entity would recognize an impairment allowance equal to its current estimate of all contractual cash flows that the entity does not expect to collect from financial assets measured at amortized cost. The entity's estimate would consider relevant information about past events, current conditions, and reasonable and supportable forecasts, which will result in recognition of lifetime expected credit losses upon loan origination. ASU 2016-13 is effective for interim and annual reporting periods beginning after December 15, 2019, with early adoption permitted for annual reporting periods beginning after December 15, 2018. We are currently assessing the effect this guidance will have on our consolidated results of operations, financial condition or cash flows. In February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842), " which for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments in its balance sheet. This standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term, on a generally straight-line basis. This guidance is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. We do not expect the adoption of this guidance to have a material effect on our consolidated results of operations or cash flows. The effect of ASU 2016-02 on our consolidated financial position will be based on leases outstanding at the time of adoption.

ORGANIZATION, BASIS OF PRESEN22

ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash and cash equivalents as reported within the condensed consolidated balance sheets to the total of the same such amounts shown within the condensed consolidated statements of cash flows: As of June 30, 2018 December 31, 2017 Cash and cash equivalents $ 5,098.5 $ 4,198.6 Restricted cash and cash equivalents (1) 60.9 64.4 Total cash, cash equivalents, and restricted cash and cash equivalents $ 5,159.4 $ 4,263.0 (1) Restricted cash and cash equivalents consist of restricted cash and restricted money market funds and are included in Restricted cash, cash equivalents and investments within noncurrent assets of our condensed consolidated balance sheets. Refer to Note 6 - Restricted Cash, Cash Equivalents and Investments for further detail.
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash and cash equivalents as reported within the condensed consolidated balance sheets to the total of the same such amounts shown within the condensed consolidated statements of cash flows: As of June 30, 2018 December 31, 2017 Cash and cash equivalents $ 5,098.5 $ 4,198.6 Restricted cash and cash equivalents (1) 60.9 64.4 Total cash, cash equivalents, and restricted cash and cash equivalents $ 5,159.4 $ 4,263.0 (1) Restricted cash and cash equivalents consist of restricted cash and restricted money market funds and are included in Restricted cash, cash equivalents and investments within noncurrent assets of our condensed consolidated balance sheets. Refer to Note 6 - Restricted Cash, Cash Equivalents and Investments for further detail.

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
Fair Value of Consideration Transferred in Acquisition	The fair value at the Effective Date of the consideration transferred in the Universal American acquisition consisted of the following: (in millions) Number of shares of Universal American common stock outstanding on April 28, 2017 (57.1 million) multiplied by the Per Share Merger Consideration $ 570.8 Assumed debt (a) 145.3 Repurchase of Preferred Shares (b) 41.0 Stock-based award cash consideration (c) 12.9 Total consideration transferred $ 770.0 (a) Following the consummation of the Universal American transaction, all of the holders of Universal American's 4.00% convertible senior notes (the "Convertible Notes") elected to convert their notes into the right to receive cash equal to the par value of the notes plus a make whole premium. We paid the noteholders the amounts due and all of the Convertible Notes were redeemed in the second quarter of 2017. The fair value of the Convertible Notes was determined based on quoted market prices; therefore, have been classified within Level 1 of the fair value hierarchy. See Universal American Convertible Notes below for further discussion of the repurchase of the Convertible Notes. (b) On the Effective Date, we redeemed an aggregate of $40.0 million of Universal American's Preferred Shares, which became redeemable by the holders on April 28, 2017, due to certain change in control provisions for the Preferred Shares. We redeemed the Preferred Shares for $41.0 million, which includes the $40.0 million par value of the Preferred Shares and $1.0 million of accrued dividends. See Universal American Mandatorily Redeemable Preferred Shares below for further discussion of the redemption of the Preferred Shares. (c) Pursuant to the terms of the Universal American acquisition, outstanding vested and unvested stock-based compensation awards as of the Effective Date converted to the right to receive cash. We estimated the fair value of these awards at the Effective Date and attributed that fair value to pre-acquisition and post-acquisition services in accordance with GAAP. Accordingly, $12.9 million of the fair value of these awards was attributed to pre-acquisition services and is included in the estimated consideration transferred, and approximately $20.0 million has been, or will be, included in our post-acquisition financial statements as compensation costs and reflected as a selling, general and administrative expense in our condensed consolidated statements of comprehensive income.
Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the final fair values of major classes of assets acquired and liabilities assumed at the Effective Date, based on our valuation assumptions, reconciled to the total consideration transferred. Assets (in millions) Cash and cash equivalents $ 66.4 Investments, including restricted investments 254.4 Premiums receivable, net 90.7 Pharmacy rebates receivable, net, and other current assets 45.6 Property, equipment and capitalized software, net 7.5 Goodwill 292.3 Other intangible assets, net 298.2 Assets of discontinued operations 219.6 Fair value of total assets acquired $ 1,274.7 Liabilities Medical benefits payable 128.1 Deferred tax liabilities, net 70.1 Other liabilities 87.8 Liabilities of discontinued operations 218.7 Fair value of liabilities assumed $ 504.7 Fair value of net assets acquired $ 770.0
Final Fair Values and Weighted Average Useful Lives for Identifiable Intangible Assets Acquired	The following table summarizes the final fair values and weighted average useful lives for identifiable intangible assets acquired in the Universal American acquisition, as of the Effective Date. Gross Fair Value (in millions) Weighted Average Useful Life (in years) Membership $ 240.0 10.0 Tradenames 36.0 13.9 Provider network 9.5 15.0 Other 12.7 6.2 Total $ 298.2 10.5
Unaudited Pro Forma Results	The following unaudited pro forma results have been prepared for comparative purposes only and do not purport to be indicative of the results of operations that would have occurred had the acquisitions actually consummated at January 1, 2017, or project the future results of the combined company. Three Months Ended June 30, Six Months Ended June 30, (in millions, except per share data) 2017 2017 Total revenues $ 4,690.8 $ 8,415.1 Net income $ 92.6 $ 151.8 Earnings per common share: Basic $ 2.08 $ 3.42 Diluted $ 2.06 $ 3.38

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Revenue by Geographic Location	Those states and the respective Medicaid premium revenue as a percentage of total consolidated premium revenue are as follows: For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 Kentucky 15% 15% 15% 16% Florida 13% 15% 13% 15% Georgia * 10% * 10% *Effective July 1, 2017, we began services under a new Medicaid contract with the State of Georgia serving TANF and CHIP beneficiaries. Due to the addition of a fourth managed care organization to the state program, our Georgia Medicaid membership declined by approximately 62,000 members as of June 30, 2018 , compared with June 30, 2017 . As a result of the decline in membership, premium revenue attributable to our Georgia Medicaid health plan accounted for less than 10% of our consolidated premium revenue for the three and six months ended June 30, 2018 .
Segment Results	A summary of financial information for our reportable segments through the gross margin level and reconciliation to income from operations is presented in the table below. For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 (in millions) Premium revenue: Medicaid Health Plans $ 2,866.2 $ 2,751.4 $ 5,676.1 $ 5,335.6 Medicare Health Plans 1,546.4 1,316.6 3,102.9 2,411.3 Medicare PDPs 200.0 225.6 459.9 493.7 Total premium revenue 4,612.6 4,293.6 9,238.9 8,240.6 Medical benefits expense: Medicaid Health Plans 2,438.6 2,386.9 4,863.0 4,697.5 Medicare Health Plans 1,281.9 1,136.9 2,589.0 2,045.1 Medicare PDPs 145.5 195.2 376.0 455.0 Total medical benefits expense 3,866.0 3,719.0 7,828.0 7,197.6 ACA industry fee expense: Medicaid Health Plans 47.8 — 97.1 — Medicare Health Plans 26.7 — 54.3 — Medicare PDPs 4.5 — 9.1 — Total ACA industry fee expense 79.0 — 160.5 — Gross margin Medicaid Health Plans 379.8 364.5 716.0 638.1 Medicare Health Plans 237.8 179.7 459.6 366.2 Medicare PDPs 50.0 30.4 74.8 38.7 Total gross margin 667.6 574.6 1,250.4 1,043.0 Investment and other income 26.4 11.4 46.3 18.6 Other expenses (1) (460.1 ) (444.1 ) (901.6 ) (816.5 ) Income from operations $ 233.9 $ 141.9 $ 395.1 $ 245.1 (1) Other expenses include selling, general and administrative expenses, Medicaid premium taxes, depreciation and amortization and interest.

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Calculation of the Weighted-Average Common Shares Outstanding - Diluted	The calculation of the weighted-average common shares outstanding — diluted is as follows: For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 Weighted-average common shares outstanding — basic 44,759,808 44,498,610 44,682,850 44,432,299 Dilutive effect of outstanding stock-based compensation awards 522,486 435,441 556,360 448,058 Weighted-average common shares outstanding — diluted 45,282,294 44,934,051 45,239,210 44,880,357 Anti-dilutive stock-based compensation awards excluded from computation 141,073 3,091 209,232 3,641

INVESTMENTS (Tables)

INVESTMENTS (Tables)	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Short-term and Long-term Investments by Security Type	Excluding restricted cash, cash equivalents and investments, the amortized cost, gross unrealized gains or losses and estimated fair value of short-term and long-term investments by security type are summarized in the following tables. Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2018 Asset-backed securities $ 87.5 $ — $ (0.7 ) $ 86.8 Corporate debt securities 680.6 0.2 (9.5 ) 671.3 Municipal securities 211.0 0.3 (1.9 ) 209.4 Residential mortgage-backed securities 7.8 — (0.2 ) 7.6 Short-term time deposits 369.2 — — 369.2 Government and agency obligations 105.0 — (1.5 ) 103.5 Other securities 67.7 — — 67.7 Total $ 1,528.8 $ 0.5 $ (13.8 ) $ 1,515.5 December 31, 2017 Asset-backed securities $ 88.9 $ — $ (0.2 ) $ 88.7 Corporate debt securities 400.6 0.7 (1.2 ) 400.1 Municipal securities 223.7 1.0 (1.9 ) 222.8 Residential mortgage-backed securities 11.2 — — 11.2 Short-term time deposits 300.4 — — 300.4 Government and agency obligations 148.7 — (1.2 ) 147.5 Other securities 65.2 — (0.2 ) 65.0 Total $ 1,238.7 $ 1.7 $ (4.7 ) $ 1,235.7
Contractual Maturities of Available-for-sale Securities	Contractual maturities of available-for-sale securities at June 30, 2018 are as follows: Total Within 1 Year 1 Through 5 Years 5 Through 10 Years Thereafter Asset-backed securities $ 86.8 $ 21.8 $ 60.8 $ 1.3 $ 2.9 Corporate debt securities 671.3 312.2 272.8 78.0 8.3 Municipal securities 209.4 10.7 128.2 70.0 0.5 Residential mortgage-backed securities 7.6 — — — 7.6 Short-term time deposits 369.2 369.2 — — — Government and agency obligations 103.5 26.8 74.8 1.9 — Other securities 67.7 52.8 — 3.1 11.8 Total $ 1,515.5 $ 793.5 $ 536.6 $ 154.3 $ 31.1

RESTRICTED INVESTMENTS (Tables)

RESTRICTED INVESTMENTS (Tables)	6 Months Ended
	Jun. 30, 2018
Restricted Investments Note [Abstract]
Schedule of Restricted Investments	The amortized cost, gross unrealized gains, gross unrealized losses and fair value of our restricted cash, cash equivalents and investment securities are as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2018 Cash $ 3.1 $ — $ — $ 3.1 Money market funds 57.8 — — 57.8 U.S. government securities and other 169.2 — (0.8 ) 168.4 Total $ 230.1 $ — $ (0.8 ) $ 229.3 December 31, 2017 Cash $ 5.7 $ — $ — $ 5.7 Money market funds 58.7 — — 58.7 U.S. government securities and other 147.4 — (0.8 ) 146.6 Total $ 211.8 $ — $ (0.8 ) $ 211.0

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Unit Award Activity	A summary of RSU, PSU and MSU award activity, at target, for the six months ended June 30, 2018 , is presented in the table below. For our PSUs and MSUs, shares attained over target upon vesting are reflected as awards granted during the period, while shares canceled due to vesting below target are reflected as awards forfeited during the period. RSUs PSUs MSUs Total Outstanding as of January 1, 2018 274,643 552,618 45,230 872,491 Granted 114,105 255,042 45,075 414,222 Vested (110,607 ) (145,359 ) (90,150 ) (346,116 ) Forfeited (8,097 ) (14,984 ) (155 ) (23,236 ) Outstanding as of June 30, 2018 270,044 647,317 — 917,361

DEBT (Tables)

DEBT (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Outstanding Debt Obligations	The following table summarizes our outstanding debt obligations and their classification in the accompanying condensed consolidated balance sheets (in millions): June 30, 2018 December 31, 2017 Long-term debt, net: 5.25% Senior Notes, due April 1, 2025 $ 1,200.0 $ 1,200.0 Revolving Credit Facility — — Debt issuance costs (16.2 ) (17.6 ) Total long-term debt, net $ 1,183.8 $ 1,182.4

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis at June 30, 2018 are as follows: Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments: Asset-backed securities $ 86.8 $ — $ 86.8 $ — Corporate debt securities 671.3 — 671.3 — Municipal securities 209.4 — 209.4 — Residential mortgage-backed securities 7.6 — 7.6 — Short-term time deposits 369.2 — 369.2 — Government and agency obligations 103.5 103.5 — — Other securities 67.7 52.8 14.9 — Total investments $ 1,515.5 $ 156.3 $ 1,359.2 $ — Restricted cash, cash equivalents and investments: Cash $ 3.1 $ 3.1 $ — $ — Money market funds 57.8 57.8 — — U.S. government securities and other 168.4 168.2 0.2 — Total restricted cash, cash equivalents and investments $ 229.3 $ 229.1 $ 0.2 $ — Assets and liabilities measured at fair value on a recurring basis at December 31, 2017 are as follows: Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments: Asset-backed securities $ 88.7 $ — $ 88.7 $ — Corporate debt securities 400.1 — 400.1 — Municipal securities 222.8 — 210.5 12.3 Residential mortgage-backed securities 11.2 — 11.2 — Short-term time deposits 300.4 — 300.4 — Government and agency obligations 147.5 147.5 — — Other securities 65.0 52.8 12.2 — Total Investments $ 1,235.7 $ 200.3 $ 1,023.1 $ 12.3 Restricted cash, cash equivalents and investments: Cash $ 5.7 $ 5.7 $ — $ — Money market funds 58.7 58.7 — — U.S. government securities and other 146.6 146.4 0.2 — Total restricted cash, cash equivalents and investments $ 211.0 $ 210.8 $ 0.2 $ —
Carrying Value and Fair Value of Long-term Debt	The following table presents the carrying value and fair value of our long-term debt outstanding as of June 30, 2018 and December 31, 2017 : Fair Value Measurements Using Carrying Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Long-term debt - June 30, 2018 $ 1,183.8 $ 1,197.1 $ — $ — Long-term debt - December 31, 2017 1,182.4 1,274.3 — —
Changes in the Fair Value of Auction Rate Securities	The following table presents the changes in the fair value of our Level 3 auction rate securities for the three and six months ended June 30, 2018 and 2017. For the Three Months Ended For the Six Months Ended 2018 2017 2018 2017 Balance at beginning of period $ 12.3 $ 12.4 $ 12.3 $ 12.4 Realized gains (losses) in earnings (1.2 ) — (1.2 ) — Changes in unrealized gains (losses) in other comprehensive income 1.4 — 1.4 Purchases, sales and redemptions (12.5 ) (0.1 ) (12.5 ) (0.1 ) Net transfers in or (out) of Level 3 — — — — Balance at end of period $ — $ 12.3 $ — $ 12.3

MEDICAL BENEFITS PAYABLE (Table

MEDICAL BENEFITS PAYABLE (Tables)	6 Months Ended
	Jun. 30, 2018
MEDICAL BENEFITS PAYABLE [Abstract]
Reconciliation of the Beginning and Ending Balances of Medical Benefits Payable, by Segment	A reconciliation of the beginning and ending balances of medical benefits payable, by segment, is as follows: Medicaid Health Plans Medicare Health Plans Medicare PDPs Consolidated For the six months ended June 30, 2018 2017 2018 2017 2018 2017 2018 2017 Beginning balance (1) $ 1,373.2 $ 1,135.8 $ 722.5 $ 510.0 $ 50.6 $ 44.7 $ 2,146.3 $ 1,690.5 Acquisitions — — — 128.1 — — — 128.1 Medical benefits incurred related to: Current year 5,029.5 4,866.4 2,709.5 2,133.2 445.1 517.7 8,184.1 7,517.3 Prior years (166.5 ) (168.9 ) (120.5 ) (88.1 ) (69.1 ) (62.7 ) (356.1 ) (319.7 ) Total 4,863.0 4,697.5 2,589.0 2,045.1 376.0 455.0 7,828.0 7,197.6 Medical benefits paid related to: Current year (3,906.0 ) (3,838.2 ) (2,065.8 ) (1,682.7 ) (414.3 ) (483.7 ) (6,386.1 ) (6,004.6 ) Prior years (834.4 ) (725.6 ) (438.1 ) (300.7 ) 29.7 19.1 (1,242.8 ) (1,007.2 ) Total (4,740.4 ) (4,563.8 ) (2,503.9 ) (1,983.4 ) (384.6 ) (464.6 ) (7,628.9 ) (7,011.8 ) Ending balance (1) $ 1,495.8 $ 1,269.5 $ 807.6 $ 699.8 $ 42.0 $ 35.1 $ 2,345.4 $ 2,004.4 (1) The Medicaid Health Plans and Consolidated beginning and ending balances for 2018 include a premium deficiency reserve for our Illinois Medicaid program ("Illinois PDR"), which amounted to $37.9 million and $45.6 million at June 30, 2018 and December 31, 2017, respectively. See Note 2 - Summary of Significant Accounting Policies in our 2017 Form 10-K for further discussion.

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	6 Months Ended
	Jun. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Total Assets and Liabilities of Discontinued Operations	The following table summarizes the total assets and liabilities of our discontinued operations: June 30, 2018 December 31, 2017 (in millions) Assets Cash and cash equivalents $ 0.4 $ 1.3 Investments 44.4 46.5 Reinsurance recoverables 167.8 166.9 Other assets 0.5 0.5 Total Assets $ 213.1 $ 215.2 Liabilities Reserves and other policy liabilities $ 150.3 $ 148.6 Other liabilities 62.8 66.6 Total liabilities 213.1 215.2

ORGANIZATION, BASIS OF PRESEN33

ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Details) member in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)memberstate	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)memberstate	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Funds Receivable/Payable for the Benefit of Members [Line Items]
Number of members | member	4.4		4.4
Number of states the entity serves | state	50		50
Premiums receivable, net	$ 700.1		$ 700.1		$ 453.4
Premiums payable, net	580		580		65.9
Funds payable for the benefit of members	1,674.5		1,674.5		1,075.9
ACA industry fee liability	321		321		0
ACA industry fee expense	79	$ 0	160.5	$ 0
Medicaid ACA industry fee reimbursement revenue	62.8		127.5
Advance Payment CMS
Funds Receivable/Payable for the Benefit of Members [Line Items]
Premiums payable, net	540.6		540.6
Funds payable for the benefit of members	341.2		341.2
State Partners | Medicaid Health Plans
Funds Receivable/Payable for the Benefit of Members [Line Items]
Premiums receivable, net	442.3		442.3
Medicare Advantage and PDP | Medicare Advantage
Funds Receivable/Payable for the Benefit of Members [Line Items]
Premiums receivable, net	244.4		244.4
Premiums receivable, net
Funds Receivable/Payable for the Benefit of Members [Line Items]
Medicaid retroactive rate change and risk score adjustments	$ 8.7		$ 8.7		$ 50.7

ORGANIZATION, BASIS OF PRESEN34

ORGANIZATION, BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents		$ 5,098.5	$ 4,198.6
Restricted cash and cash equivalents		60.9	64.4
Total cash, cash equivalents, and restricted cash and cash equivalents	[1]	$ 5,159.4	$ 4,263	$ 4,093.6	$ 4,121.3
[1]	Beginning and ending cash, cash equivalents and restricted cash and cash equivalents balances have been retrospectively adjusted to reflect the adoption of ASU 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash" effective January 1, 2018. See Note 1 - Organization, Basis of Presentation and Significant Accounting Policies for further discussion.

ACQUISITIONS - Narrative (Detai

ACQUISITIONS - Narrative (Details) $ / shares in Units, member in Thousands	May 01, 2017member	Apr. 28, 2017USD ($)member$ / shares	May 31, 2018USD ($)	Apr. 30, 2011USD ($)$ / sharesshares	Jun. 30, 2018USD ($)member$ / shares	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)member$ / shares	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Jul. 23, 2018USD ($)	May 01, 2018member	Dec. 31, 2017USD ($)$ / shares	Apr. 07, 2017	Mar. 22, 2017USD ($)	Jan. 31, 2016USD ($)	Jun. 30, 2015USD ($)	Nov. 30, 2013USD ($)
Business Acquisition [Line Items]
Number of members | member					4,400		4,400
Payments for repurchase of preferred shares		$ 40,000,000
Goodwill					$ 677,400,000		$ 677,400,000					$ 660,700,000
Preferred stock, par value (in USD per share) | $ / shares					$ 0.01		$ 0.01					$ 0.01
Preferred shares redeemed						$ 41,000,000		$ 41,000,000
Preferred shares par value						40,000,000		40,000,000
Preferred shares accrued dividends						1,000,000
Revenue					$ 4,639,000,000	4,305,000,000	$ 9,285,200,000	8,259,200,000
Pre-tax income					$ 229,900,000	114,700,000	$ 388,400,000	217,900,000
Senior Notes | 5.75 Percent Senior Notes Due 2020, Issued 2015 [Member]
Business Acquisition [Line Items]
Aggregate principal amount																$ 300,000,000	$ 600,000,000
Interest rate					5.75%		5.75%						5.75%
Universal American
Business Acquisition [Line Items]
Preferred shares issued				$ 40,000,000
Preferred stock issued (in shares) | shares				1,600,000
Preferred stock, par value (in USD per share) | $ / shares				$ 0.01
Liquidation preference (in USD per share) | $ / shares				$ 25
Revenue					$ 385,100,000	235,100,000	$ 769,900,000	31,700,000
Pre-tax income					13,000,000		31,700,000
Universal American | Senior Unsecured Notes | Convertible Senior Notes Due 2021
Business Acquisition [Line Items]
Proceeds from convertible notes									$ 115,000,000
Interest rate									4.00%
Meridian
Business Acquisition [Line Items]
Acquisition consideration transferred			$ 2,500,000,000
Number of members | member											1,100
Committed bridge financing			2,500,000,000
Phoenix Health Plan
Business Acquisition [Line Items]
Number of members acquired | member	42
Universal American
Business Acquisition [Line Items]
Acquisition consideration transferred		$ 770,000,000
Number of members acquired | member		119
Cash purchase price (in USD per share) | $ / shares		$ 10
Assumption of convertible debt		$ 145,300,000
Payments for repurchase of preferred shares		40,000,000
Net deferred tax liabilities acquired		70,100,000
Goodwill		292,300,000
Expected tax deductible amount of goodwill and other intangible assets acquired		0
Transaction and integration-related costs incurred					$ 1,200,000	$ 25,600,000	$ 3,900,000	$ 26,700,000
Universal American | Preferred Stock
Business Acquisition [Line Items]
Consideration transferred, preferred shares redemption amount		$ 41,000,000
Minimum | Senior Notes | 5.75 Percent Senior Notes Due 2020, Issued 2015 [Member]
Business Acquisition [Line Items]
Aggregate principal amount																	600,000,000
Minimum | Meridian
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			800,000,000
Maximum | Senior Notes | 5.75 Percent Senior Notes Due 2020, Issued 2015 [Member]
Business Acquisition [Line Items]
Aggregate principal amount																	$ 1,000,000,000
Maximum | Meridian
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			$ 1,200,000,000
Revolving Credit Facility
Business Acquisition [Line Items]
Credit facility, maximum borrowing capacity														$ 1,000,000,000	$ 850,000,000
Revolving Credit Facility | Subsequent Event
Business Acquisition [Line Items]
Credit facility, maximum borrowing capacity										$ 1,300,000,000

ACQUISITIONS - Consideration Tr

ACQUISITIONS - Consideration Transferred (Details) - USD ($) $ in Millions	Apr. 28, 2017	Jun. 30, 2018	Dec. 31, 2017
Business Combination, Consideration Transferred [Abstract]
Common stock, outstanding (in shares)		44,767,277	44,522,988
Payments for repurchase of preferred shares	$ 40
Payments for repurchase of preferred shares and accrued dividends	41
Payments of accrued dividends	1
Unrecognized stock based compensation cost	$ 20
Senior Notes | 4.00% Convertible Senior Notes
Business Combination, Consideration Transferred [Abstract]
Interest rate	4.00%
Universal American
Business Combination, Consideration Transferred [Abstract]
Cash consideration transferred	$ 570.8
Assumed debt	145.3
Total consideration transferred	770
Payments for repurchase of preferred shares	40
Universal American | Stock-based Award
Business Combination, Consideration Transferred [Abstract]
Equity interests issued	12.9
Universal American | Preferred Stock
Business Combination, Consideration Transferred [Abstract]
Equity interests issued	$ 41
Universal American
Business Combination, Consideration Transferred [Abstract]
Common stock, outstanding (in shares)	57,100,000

ACQUISITIONS - Assets Acquired

ACQUISITIONS - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Apr. 28, 2017
Assets
Goodwill	$ 677.4	$ 660.7
Universal American
Assets
Cash and cash equivalents			$ 66.4
Investments, including restricted investments			254.4
Premiums receivable, net			90.7
Pharmacy rebates receivable, net, and other current assets			45.6
Property, equipment and capitalized software, net			7.5
Goodwill			292.3
Other intangible assets, net			298.2
Assets of discontinued operations			219.6
Fair value of total assets acquired			1,274.7
Liabilities
Medical benefits payable			128.1
Deferred tax liabilities, net			70.1
Other liabilities			87.8
Liabilities of discontinued operations			218.7
Fair value of liabilities assumed			504.7
Fair value of net assets acquired			$ 770

ACQUISITIONS - Fair Values and

ACQUISITIONS - Fair Values and Useful Lives for Intangibles Acquired (Details) - Universal American $ in Millions	Apr. 28, 2017USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Gross fair value	$ 298.2
Weighted average useful life	10 years 6 months
Membership
Acquired Finite-Lived Intangible Assets [Line Items]
Gross fair value	$ 240
Weighted average useful life	10 years
Tradenames
Acquired Finite-Lived Intangible Assets [Line Items]
Gross fair value	$ 36
Weighted average useful life	13 years 11 months
Provider network
Acquired Finite-Lived Intangible Assets [Line Items]
Gross fair value	$ 9.5
Weighted average useful life	15 years
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross fair value	$ 12.7
Weighted average useful life	6 years 2 months

ACQUISITIONS - Pro Forma Financ

ACQUISITIONS - Pro Forma Financial Information (Details) - PHP and Universal American - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Business Acquisition, Pro Forma Information [Abstract]
Total revenues	$ 4,690.8	$ 8,415.1
Net income	$ 92.6	$ 151.8
Earnings per common share:
Basic (in USD per share)	$ 2.08	$ 3.42
Diluted (in USD per share)	$ 2.06	$ 3.38

SEGMENT REPORTING - Narrative (

SEGMENT REPORTING - Narrative (Details) beneficiary in Thousands	1 Months Ended		6 Months Ended
	Jul. 31, 2018beneficiary	Apr. 30, 2018	Jun. 30, 2018segment
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Medical Services Managed Care Plan | Florida | Medicaid Health Plans
Segment Reporting Information [Line Items]
Term of agreement		5 years
Medical Services Managed Care Plan | Florida | Subsequent Event | Medicaid Health Plans
Segment Reporting Information [Line Items]
Number of beneficiaries	60
Term of agreement	5 years
Serious Mental Illness Specialty Plan | Florida | Subsequent Event | Medicaid Health Plans
Segment Reporting Information [Line Items]
Number of beneficiaries	75

SEGMENT REPORTING - Revenue by

SEGMENT REPORTING - Revenue by Geographic Location (Details) - member member in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of members	4,400		4,400
Kentucky
Revenues from External Customers and Long-Lived Assets [Line Items]
Premium revenue as a percentage of total consolidated premium revenue	15.00%	15.00%	15.00%	16.00%
Florida
Revenues from External Customers and Long-Lived Assets [Line Items]
Premium revenue as a percentage of total consolidated premium revenue	13.00%	15.00%	13.00%	15.00%
Georgia
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of members	62		62
Premium revenue as a percentage of total consolidated premium revenue		10.00%	10.00%	10.00%

SEGMENT REPORTING - Segment Res

SEGMENT REPORTING - Segment Results (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Premium revenue	$ 4,612.6	$ 4,293.6	$ 9,238.9	$ 8,240.6
Medical benefits expense	3,866	3,719	7,828	7,197.6
ACA industry fee expense	79	0	160.5	0
Investment and other income	26.4	11.4	46.3	18.6
Other expenses	(460.1)	(444.1)	(901.6)	(816.5)
Income from operations	233.9	141.9	395.1	245.1
Operating Segments
Segment Reporting Information [Line Items]
Gross margin	667.6	574.6	1,250.4	1,043
Segment Reconciling Items
Segment Reporting Information [Line Items]
Investment and other income	26.4	11.4	46.3	18.6
Medicaid Health Plans | Operating Segments
Segment Reporting Information [Line Items]
Premium revenue	2,866.2	2,751.4	5,676.1	5,335.6
Medical benefits expense	2,438.6	2,386.9	4,863	4,697.5
ACA industry fee expense	47.8	0	97.1	0
Gross margin	379.8	364.5	716	638.1
Medicare Health Plans | Operating Segments
Segment Reporting Information [Line Items]
Premium revenue	1,546.4	1,316.6	3,102.9	2,411.3
Medical benefits expense	1,281.9	1,136.9	2,589	2,045.1
ACA industry fee expense	26.7	0	54.3	0
Gross margin	237.8	179.7	459.6	366.2
Medicare PDPs | Operating Segments
Segment Reporting Information [Line Items]
Premium revenue	200	225.6	459.9	493.7
Medical benefits expense	145.5	195.2	376	455
ACA industry fee expense	4.5	0	9.1	0
Gross margin	$ 50	$ 30.4	$ 74.8	$ 38.7

EARNINGS PER COMMON SHARE - Cal

EARNINGS PER COMMON SHARE - Calculation of Weighted-Average Common Shares Outstanding (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Weighted-average common shares outstanding — basic (in shares)	44,759,808	44,498,610	44,682,850	44,432,299
Dilutive effect of outstanding stock-based compensation awards (in shares)	522,486	435,441	556,360	448,058
Weighted-average common shares outstanding — diluted (in shares)	45,282,294	44,934,051	45,239,210	44,880,357
Anti-dilutive stock-based compensation awards excluded from computation (in shares)	141,073	3,091	209,232	3,641

INVESTMENTS - Short-term and Lo

INVESTMENTS - Short-term and Long-term Investments by Security Type (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,528.8	$ 1,238.7
Gross Unrealized Gains	0.5	1.7
Gross Unrealized Losses	(13.8)	(4.7)
Estimated Fair Value	1,515.5	1,235.7
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	87.5	88.9
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(0.7)	(0.2)
Estimated Fair Value	86.8	88.7
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	680.6	400.6
Gross Unrealized Gains	0.2	0.7
Gross Unrealized Losses	(9.5)	(1.2)
Estimated Fair Value	671.3	400.1
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	211	223.7
Gross Unrealized Gains	0.3	1
Gross Unrealized Losses	(1.9)	(1.9)
Estimated Fair Value	209.4	222.8
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7.8	11.2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(0.2)	0
Estimated Fair Value	7.6	11.2
Short-term time deposits
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	369.2	300.4
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	369.2	300.4
Government and agency obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	105	148.7
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1.5)	(1.2)
Estimated Fair Value	103.5	147.5
Other securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	67.7	65.2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(0.2)
Estimated Fair Value	$ 67.7	$ 65

INVESTMENTS - Contractual Matur

INVESTMENTS - Contractual Maturities of Available-for-sale Securities (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	$ 1,515.5	$ 1,235.7
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	86.8	88.7
Within 1 Year	21.8
1 Through 5 Years	60.8
5 Through 10 Years	1.3
Thereafter	2.9
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	671.3	400.1
Within 1 Year	312.2
1 Through 5 Years	272.8
5 Through 10 Years	78
Thereafter	8.3
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	209.4	222.8
Within 1 Year	10.7
1 Through 5 Years	128.2
5 Through 10 Years	70
Thereafter	0.5
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	7.6	11.2
Within 1 Year	0
1 Through 5 Years	0
5 Through 10 Years	0
Thereafter	7.6
Short-term time deposits
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	369.2	300.4
Within 1 Year	369.2
1 Through 5 Years	0
5 Through 10 Years	0
Thereafter	0
Government and agency obligations
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	103.5	147.5
Within 1 Year	26.8
1 Through 5 Years	74.8
5 Through 10 Years	1.9
Thereafter	0
Other securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	67.7	$ 65
Within 1 Year	52.8
1 Through 5 Years	0
5 Through 10 Years	3.1
Thereafter	11.8
Debt securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	1,515.5
Within 1 Year	793.5
1 Through 5 Years	536.6
5 Through 10 Years	154.3
Thereafter	$ 31.1

INVESTMENTS - Narrative (Detail

INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Proceeds from sale of available-for-sale investments	$ 138,600	$ 74,700	$ 218,800	$ 82,900
Debt Securities, Available-for-sale, Realized Loss	1,700		2,900
Realized gains and losses on sales and redemptions of investments		0		0
Other than temporary impairment losses		$ 0	0	$ 0
Available-for-sale securities, gross realized gains	$ 0		$ 0

RESTRICTED INVESTMENTS - Schedu

RESTRICTED INVESTMENTS - Schedule of Restricted Investments (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	$ 230.1	$ 211.8
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(0.8)	(0.8)
Estimated Fair Value	229.3	211
Cash
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	3.1	5.7
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	3.1	5.7
Money market funds
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	57.8	58.7
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	57.8	58.7
U.S. government securities and other
Restricted Cash and Cash Equivalents Items [Line Items]
Amortized Cost	169.2	147.4
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(0.8)	(0.8)
Estimated Fair Value	$ 168.4	$ 146.6

RESTRICTED INVESTMENTS - Narrat

RESTRICTED INVESTMENTS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018
Restricted Investments Note [Abstract]
Realized gains (losses) on restricted investments	$ 0	$ 0

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 18	$ 13.9	$ 30.1	$ 23.5
Unrecognized compensation cost	$ 95.3		$ 95.3
Weighted-average period over which compensation costs are expected to be recognized			2 years 15 days
Closing common stock price (in USD per share)	$ 246.24		$ 246.24
Grants in period, weighted average grant date fair value (in USD per share)			$ 199.72
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 29.9		$ 29.9

STOCK-BASED COMPENSATION - Summ

STOCK-BASED COMPENSATION - Summary of Stock Unit Award Activity (Details)	6 Months Ended
	Jun. 30, 2018shares
Equity Instruments Other than Options [Roll Forward]
Outstanding as of beginning of period (in shares)	872,491
Granted (in shares)	414,222
Vested (in shares)	(346,116)
Forfeited (in shares)	(23,236)
Outstanding at end of period (in shares)	917,361
RSUs
Equity Instruments Other than Options [Roll Forward]
Outstanding as of beginning of period (in shares)	274,643
Granted (in shares)	114,105
Vested (in shares)	(110,607)
Forfeited (in shares)	(8,097)
Outstanding at end of period (in shares)	270,044
PSUs
Equity Instruments Other than Options [Roll Forward]
Outstanding as of beginning of period (in shares)	552,618
Granted (in shares)	255,042
Vested (in shares)	(145,359)
Forfeited (in shares)	(14,984)
Outstanding at end of period (in shares)	647,317
MSUs
Equity Instruments Other than Options [Roll Forward]
Outstanding as of beginning of period (in shares)	45,230
Granted (in shares)	45,075
Vested (in shares)	(90,150)
Forfeited (in shares)	(155)
Outstanding at end of period (in shares)	0

DEBT - Schedule of Outstanding

DEBT - Schedule of Outstanding Debt Obligations (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017	Mar. 22, 2017
Long-term debt, net
Debt issuance costs	$ (16,200,000)	$ (17,600,000)
Total long-term debt, net	1,183,800,000	1,182,400,000
Revolving Credit Facility
Long-term debt, net
Revolving Credit Facility	0	0	$ 100,000,000
Senior Notes | 5.25% Senior Notes, due April 1, 2025
Long-term debt, net
Senior notes	$ 1,200,000,000	$ 1,200,000,000
Interest rate	5.25%		5.25%

DEBT - Narrative (Details)

DEBT - Narrative (Details) - USD ($)	Apr. 07, 2017	Mar. 22, 2017	Mar. 31, 2017	Jun. 30, 2015	Jun. 30, 2018	Dec. 31, 2017	Jan. 31, 2016	Nov. 30, 2013
Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings outstanding		$ 100,000,000			$ 0	$ 0
Credit facility, maximum borrowing capacity		$ 1,000,000,000					$ 850,000,000
Repayments of debt			$ 100,000,000
Senior Notes | 5.25% Senior Notes, due April 1, 2025
Debt Instrument [Line Items]
Interest rate		5.25%			5.25%
Aggregate principal amount		$ 1,200,000,000
Aggregate net proceeds from the issuance of debt		$ 1,182,200,000
Senior Notes | 5.75% Senior Notes, due November 15, 2020
Debt Instrument [Line Items]
Interest rate	5.75%				5.75%
Aggregate principal amount				$ 300,000,000				$ 600,000,000
Issue price percentage				104.50%
Debt repurchase amount	$ 900,000,000
Redemption price	102.875%

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value (Details) - Fair value, measurements, recurring - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 1,515.5	$ 1,235.7
Restricted cash, cash equivalents and investments	229.3	211
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	86.8	88.7
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	671.3	400.1
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	209.4	222.8
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7.6	11.2
Short-term time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	369.2	300.4
Government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	103.5	147.5
Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	67.7	65
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	3.1	5.7
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	57.8	58.7
U.S. government securities and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	168.4	146.6
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	156.3	200.3
Restricted cash, cash equivalents and investments	229.1	210.8
Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	103.5	147.5
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	52.8	52.8
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	3.1	5.7
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	57.8	58.7
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government securities and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	168.2	146.4
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,359.2	1,023.1
Restricted cash, cash equivalents and investments	0.2	0.2
Significant Other Observable Inputs (Level 2) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	86.8	88.7
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	671.3	400.1
Significant Other Observable Inputs (Level 2) | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	209.4	210.5
Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7.6	11.2
Significant Other Observable Inputs (Level 2) | Short-term time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	369.2	300.4
Significant Other Observable Inputs (Level 2) | Government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Other Observable Inputs (Level 2) | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	14.9	12.2
Significant Other Observable Inputs (Level 2) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	0	0
Significant Other Observable Inputs (Level 2) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	0	0
Significant Other Observable Inputs (Level 2) | U.S. government securities and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	0.2	0.2
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	12.3
Restricted cash, cash equivalents and investments	0	0
Significant Unobservable Inputs (Level 3) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Unobservable Inputs (Level 3) | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	12.3
Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Unobservable Inputs (Level 3) | Short-term time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Unobservable Inputs (Level 3) | Government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Unobservable Inputs (Level 3) | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Significant Unobservable Inputs (Level 3) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	0	0
Significant Unobservable Inputs (Level 3) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	0	0
Significant Unobservable Inputs (Level 3) | U.S. government securities and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash, cash equivalents and investments	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Carry

FAIR VALUE MEASUREMENTS - Carrying Value and Fair Value of Long-term Debt (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017	Mar. 22, 2017
Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings outstanding	$ 0	$ 0	$ 100,000,000
Quoted Prices in Active Markets for Identical Assets (Level 1)
Debt Instrument [Line Items]
Long-term debt, fair value	1,197,100,000	1,274,300,000
Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3)
Debt Instrument [Line Items]
Long-term debt, fair value	0	0
Carrying Value
Debt Instrument [Line Items]
Long-term debt, fair value	$ 1,183,800,000	$ 1,182,400,000

FAIR VALUE MEASUREMENTS - Chang

FAIR VALUE MEASUREMENTS - Changes in the Fair Value of Auction Rate Securities (Details) - Significant Unobservable Inputs (Level 3) - Fair value, measurements, recurring - Asset backed securities - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 12.3	$ 12.4	$ 12.3	$ 12.4
Realized gains (losses) in earnings	(1.2)	0	(1.2)	0
Changes in unrealized gains (losses) in other comprehensive income	1.4	0	1.4
Purchases, sales and redemptions	(12.5)	(0.1)	(12.5)	(0.1)
Net transfers in or (out) of Level 3	0	0	0	0
Ending balance	$ 0	$ 12.3	$ 0	$ 12.3

MEDICAL BENEFITS PAYABLE - Reco

MEDICAL BENEFITS PAYABLE - Reconciliation of Beginning and Ending Balances, by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Reconciliation of the beginning and ending balance of medical benefits payable [Roll Forward]
Beginning balance (1)			$ 2,146.3	$ 1,690.5
Acquisitions			0	128.1
Medical benefits incurred related to
Current year			8,184.1	7,517.3
Prior years	$ (356.1)	$ (319.7)	(356.1)	(319.7)
Total			7,828	7,197.6
Medical benefits paid related to
Current year			(6,386.1)	(6,004.6)
Prior years			(1,242.8)	(1,007.2)
Total			(7,628.9)	(7,011.8)
Ending balance (1)	2,345.4	2,004.4	2,345.4	2,004.4
Premium deficiency reserve	37.9		37.9		$ 45.6
Medicaid Health Plans
Reconciliation of the beginning and ending balance of medical benefits payable [Roll Forward]
Beginning balance (1)			1,373.2	1,135.8
Acquisitions			0	0
Medical benefits incurred related to
Current year			5,029.5	4,866.4
Prior years			(166.5)	(168.9)
Total			4,863	4,697.5
Medical benefits paid related to
Current year			(3,906)	(3,838.2)
Prior years			(834.4)	(725.6)
Total			(4,740.4)	(4,563.8)
Ending balance (1)	1,495.8	1,269.5	1,495.8	1,269.5
Medicare Health Plans
Reconciliation of the beginning and ending balance of medical benefits payable [Roll Forward]
Beginning balance (1)			722.5	510
Acquisitions			0	128.1
Medical benefits incurred related to
Current year			2,709.5	2,133.2
Prior years			(120.5)	(88.1)
Total			2,589	2,045.1
Medical benefits paid related to
Current year			(2,065.8)	(1,682.7)
Prior years			(438.1)	(300.7)
Total			(2,503.9)	(1,983.4)
Ending balance (1)	807.6	699.8	807.6	699.8
Medicare PDPs
Reconciliation of the beginning and ending balance of medical benefits payable [Roll Forward]
Beginning balance (1)			50.6	44.7
Acquisitions			0	0
Medical benefits incurred related to
Current year			445.1	517.7
Prior years			(69.1)	(62.7)
Total			376	455
Medical benefits paid related to
Current year			(414.3)	(483.7)
Prior years			29.7	19.1
Total			(384.6)	(464.6)
Ending balance (1)	$ 42	$ 35.1	$ 42	$ 35.1

MEDICAL BENEFITS PAYABLE - Narr

MEDICAL BENEFITS PAYABLE - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Favorable development of medical benefits payable	$ 356.1	$ 319.7	$ 356.1	$ 319.7
Favorable development of medical benefits payable excluding the release of the provision for moderately adverse conditions			173.4	178.8
Medicaid Health Plans
Liability for Claims and Claims Adjustment Expense [Line Items]
Favorable development of medical benefits payable			$ 166.5	$ 168.9

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	34.10%	35.40%	34.80%	35.10%
Discrete tax benefit	$ 1.3

DISCONTINUED OPERATIONS (Detail

DISCONTINUED OPERATIONS (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Liabilities
Total liabilities	$ 213.1	$ 215.2
Traditional Insurance Business | Discontinued operations, held-for-sale
Assets
Cash and cash equivalents	0.4	1.3
Investments	44.4	46.5
Reinsurance recoverables	167.8	166.9
Other assets	0.5	0.5
Total Assets	213.1	215.2
Liabilities
Reserves and other policy liabilities	150.3	148.6
Other liabilities	62.8	66.6
Total liabilities	$ 213.1	$ 215.2

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) $ in Millions

1 Months Ended

3 Months Ended

6 Months Ended

Dec. 31, 2017USD ($)

Jun. 30, 2017USD ($)

Apr. 30, 2017USD ($)

Oct. 31, 2016USD ($)

Sep. 30, 2016USD ($)

Jun. 30, 2018USD ($)employeeassociateformer_officer

Jun. 30, 2017USD ($)

Jun. 30, 2018USD ($)employeeassociateformer_officer

Jun. 30, 2017USD ($)

Jun. 30, 2013officeremployee

Jan. 31, 2012employeeformer_officer

Jan. 31, 2008action

Loss Contingencies [Line Items]

Number of former officers receiving notices of cross appeal | officer

3

Number of former employees found guilty and appealing | employee

4

Legal fees

$ 0.2

$ 3

$ 0.7

$ 5.5

Derivative Lawsuits

Loss Contingencies [Line Items]

Number of former officers receiving notices of cross appeal | former_officer

3

3

Number of former associates being pursued in action filed by entity | associate

2

2

Number of former employees found guilty and appealing | employee

4

Number of former employees being pursued in action filed by entity

5

5

5

Number of actions filed in the federal and state courts between October 2007 and January 2008 | action

6

Number of former executives being pursued in action filed by entity | employee

3

Legal fees

$ 236.9

Derivative Lawsuits | Mr. Farha Case

Loss Contingencies [Line Items]

Settlement agreement, amount awarded

$ 7.5

$ 7.5

Maximum legal fee obligation

$ 7.5

Derivative Lawsuits | Mr. Farha Case | Securities and Exchange Commission (SEC)

Loss Contingencies [Line Items]

Settlement agreement, amount awarded

12.5

Derivative Lawsuits | Mr. Behrens Case

Loss Contingencies [Line Items]

Settlement agreement, amount awarded

1.5

$ 1.5

Maximum legal fee obligation

$ 1.5

Derivative Lawsuits | Mr. Behrens Case | Securities and Exchange Commission (SEC)

Loss Contingencies [Line Items]

Settlement agreement, amount awarded

$ 4.5

$ 4.5

Derivative Lawsuits | Mr. Bereday Case

Loss Contingencies [Line Items]

Maximum legal fee obligation

$ 2.5

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - USD ($)	Jul. 23, 2018	Mar. 22, 2017	Jan. 31, 2016
Revolving Credit Agreement Due July 2023 | Minimum | ABR Loans | London Interbank Offered Rate (LIBOR) | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate	0.375%
Revolving Credit Agreement Due July 2023 | Minimum | Eurodollar | London Interbank Offered Rate (LIBOR) | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate	1.375%
Revolving Credit Agreement Due July 2023 | Maximum | ABR Loans | London Interbank Offered Rate (LIBOR) | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate	1.00%
Revolving Credit Agreement Due July 2023 | Maximum | Eurodollar | London Interbank Offered Rate (LIBOR) | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate	2.00%
Revolving Credit Facility
Subsequent Event [Line Items]
Credit facility, maximum borrowing capacity		$ 1,000,000,000	$ 850,000,000
Revolving Credit Facility | Subsequent Event
Subsequent Event [Line Items]
Credit facility, maximum borrowing capacity	$ 1,300,000,000
Accordion feature amount	$ 500,000,000
Revolving Credit Facility | Minimum | Subsequent Event
Subsequent Event [Line Items]
Unused commitment fee percentage	0.20%
Revolving Credit Facility | Maximum | Subsequent Event
Subsequent Event [Line Items]
Unused commitment fee percentage	0.30%