BASIS OF PRESENTATION AND SIGNIFICANT EVENTS	3 Months Ended
Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION AND SIGNIFICANT EVENTS	BASIS OF PRESENTATION AND SIGNIFICANT EVENTS The accompanying condensed consolidated financial statements are presented in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the disclosures normally required by accounting principles generally accepted in the United States of America, or GAAP, or those normally made in an Annual Report on Form 10-K. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. For further information, the reader of this Form 10-Q should refer to our Form 10-K for the year ended December 31, 2018, that was filed with the Securities and Exchange Commission, or the SEC, on February 21, 2019. We refer to the Form 10-K as the “2018 Form 10-K” in this document. References throughout this document to “we,” “us,” “our,” “Company,” and “Humana” mean Humana Inc. and its subsidiaries. The preparation of our condensed consolidated financial statements in accordance with GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. The areas involving the most significant use of estimates are the estimation of benefits payable, the impact of risk adjustment provisions related to our Medicare contracts, the valuation and related impairment recognition of investment securities, and the valuation and related impairment recognition of long-lived assets, including goodwill. These estimates are based on knowledge of current events and anticipated future events, and accordingly, actual results may ultimately differ materially from those estimates. Refer to Note 2 to the consolidated financial statements included in our 2018 Form 10-K for information on accounting policies that we consider in preparing our consolidated financial statements. The financial information has been prepared in accordance with our customary accounting practices and has not been audited. In our opinion, the information presented reflects all adjustments necessary for a fair statement of interim results. All such adjustments are of a normal and recurring nature. Revenue Recognition Our revenues include premium and service revenues. Service revenues include administrative service fees that are recorded based upon established per member per month rates and the number of members for the month and are recognized as services are provided for the month. Additionally, service revenues include net patient service revenues that are recorded based upon established billing rates, less allowances for contractual adjustments, and are recognized as services are provided. For more information about our revenues, refer to Note 2 to the consolidated financial statements included in our 2018 Form 10-K for information on accounting policies that we consider in preparing our consolidated financial statements. See Note 15 for disaggregation of revenue by segment and type. At March 31, 2019, accounts receivable related to services were $136 million. For the three months ended March 31, 2019, we had no material bad-debt expense and there were no material contract assets, contract liabilities or deferred contract costs recorded on the condensed consolidated balance sheet at March 31, 2019. For the three months ended March 31, 2019, services revenue recognized from performance obligations related to prior periods (for example, due to changes in transaction price), was not material. Further, services revenue expected to be recognized in any future year related to remaining performance obligations was not material. Equity Method Investment in Kindred at Home In the third quarter of 2018, we, along with TPG Capital, or TPG, and Welsh, Carson, Anderson & Stowe, or WCAS, completed the acquisitions of Kindred Healthcare, Inc., or Kindred, and privately-held Curo Health Services, or Curo, respectively, merging Curo with the hospice business of the Kindred at Home Division, or Kindred at Home. As part of these transactions, we acquired a 40% minority interest in Kindred at Home, a leading home health and hospice company, for total cash consideration of approximately $1.1 billion. Earnings from Kindred at Home are included in our consolidated statement of income in the line captioned "Equity in net earnings of Kindred at Home." We account for our 40% investment in Kindred at Home using the equity method of accounting. This investment is reflected as "Equity method investment in Kindred at Home" in our condensed consolidated balance sheets, with our share of income or loss reported as "Equity in net earnings of Kindred at Home" in our condensed consolidated statements of income. We entered into a shareholders agreement with TPG and WCAS, the Sponsors, that provides for certain rights and obligations of each party. The shareholders agreement with the Sponsors includes a put option under which they have the right to require us to purchase their interest in the joint venture beginning on July 2, 2021 and ending on July 1, 2022. Likewise, we have a call option under which we have the right to require the Sponsors to sell their interest in the joint venture to Humana beginning on July 2, 2022 and ending on July 1, 2023. The put and call options, which are exercisable at a fixed EBITDA multiple and provide a minimum return on the Sponsor's investment if exercised, are measured at fair value each period using a Monte Carlo simulation. The simulation relies on assumptions around Kindred at Home's equity value, risk free interest rates, volatility, and the details specific to the put and call options. The final purchase price allocation resulted in approximately $1 billion being allocated to the investment and $236 million and $291 million allocated to the put and call options, respectively. The fair values of the put option and call option were $234 million and $217 million, respectively, at March 31, 2019. The put option is included within other long-term liabilities and the call option is included within other long-term assets. The change in fair value of the put and call options is reflected as "Other expense, net" in our condensed consolidated statements of income. Health Care Reform The Patient Protection and Affordable Care Act and The Health Care and Education Reconciliation Act of 2010 (which we collectively refer to as the Health Care Reform Law) enacted significant reforms to various aspects of the U.S. health insurance industry. Certain of these reforms became effective January 1, 2014, including an annual insurance industry premium-based fee. The Continuing Resolution bill, H.R. 195, enacted on January 22, 2018, included a one year suspension in 2019 of the health insurance industry fee, but under current law, the fee is scheduled to resume in calendar year 2020. In October 2018, we paid the federal government $1.04 billion for the annual health insurance industry fee attributed to calendar year 2018. This fee, fixed in amount by law and apportioned to insurance carriers based on market share, was not deductible for tax purposes. Each year on January 1, except when suspended, we record a liability for this fee in trade accounts payable and accrued expenses which we carry until the fee is paid. We record a corresponding deferred cost in other current assets in our condensed consolidated financial statements which is amortized ratably to expense over the calendar year. Amortization of the deferred cost was recorded in operating cost expense of approximately $263 million for the three months ended March 31, 2018, resulting from the amortization of the 2018 annual health insurance industry fee.

BASIS OF PRESENTATION AND SIGNIFICANT EVENTS

The accompanying condensed consolidated financial statements are presented in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the disclosures normally required by accounting principles generally accepted in the United States of America, or GAAP, or those normally made in an Annual Report on Form 10-K. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. For further information, the reader of this Form 10-Q should refer to our Form 10-K for the year ended December 31, 2018, that was filed with the Securities and Exchange Commission, or the SEC, on February 21, 2019. We refer to the Form 10-K as the “2018 Form 10-K” in this document. References throughout this document to “we,” “us,” “our,” “Company,” and “Humana” mean Humana Inc. and its subsidiaries.

The preparation of our condensed consolidated financial statements in accordance with GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. The areas involving the most significant use of estimates are the estimation of benefits payable, the impact of risk adjustment provisions related to our Medicare contracts, the valuation and related impairment recognition of investment securities, and the valuation and related impairment recognition of long-lived assets, including goodwill. These estimates are based on knowledge of current events and anticipated future events, and accordingly, actual results may ultimately differ materially from those estimates. Refer to Note 2 to the consolidated financial statements included in our 2018 Form 10-K for information on accounting policies that we consider in preparing our consolidated financial statements.

The financial information has been prepared in accordance with our customary accounting practices and has not been audited. In our opinion, the information presented reflects all adjustments necessary for a fair statement of interim results. All such adjustments are of a normal and recurring nature.

Revenue Recognition

Our revenues include premium and service revenues. Service revenues include administrative service fees that are recorded based upon established per member per month rates and the number of members for the month and are recognized as services are provided for the month. Additionally, service revenues include net patient service revenues that are recorded based upon established billing rates, less allowances for contractual adjustments, and are recognized as services are provided. For more information about our revenues, refer to Note 2 to the consolidated financial statements included in our 2018 Form 10-K for information on accounting policies that we consider in preparing our consolidated financial statements. See Note 15 for disaggregation of revenue by segment and type.

At March 31, 2019, accounts receivable related to services were $136 million. For the three months ended March 31, 2019, we had no material bad-debt expense and there were no material contract assets, contract liabilities or deferred contract costs recorded on the condensed consolidated balance sheet at March 31, 2019.

For the three months ended March 31, 2019, services revenue recognized from performance obligations related to prior periods (for example, due to changes in transaction price), was not material. Further, services revenue expected to be recognized in any future year related to remaining performance obligations was not material.

Equity Method Investment in Kindred at Home

In the third quarter of 2018, we, along with TPG Capital, or TPG, and Welsh, Carson, Anderson & Stowe, or WCAS, completed the acquisitions of Kindred Healthcare, Inc., or Kindred, and privately-held Curo Health Services, or Curo, respectively, merging Curo with the hospice business of the Kindred at Home Division, or Kindred at Home. As part of these transactions, we acquired a 40% minority interest in Kindred at Home, a leading home health and hospice company, for total cash consideration of approximately $1.1 billion. Earnings from Kindred at Home are included in our consolidated statement of income in the line captioned "Equity in net earnings of Kindred at Home."

We account for our 40% investment in Kindred at Home using the equity method of accounting. This investment is reflected as "Equity method investment in Kindred at Home" in our condensed consolidated balance sheets, with our share of income or loss reported as "Equity in net earnings of Kindred at Home" in our condensed consolidated statements of income.

We entered into a shareholders agreement with TPG and WCAS, the Sponsors, that provides for certain rights and obligations of each party. The shareholders agreement with the Sponsors includes a put option under which they have the right to require us to purchase their interest in the joint venture beginning on July 2, 2021 and ending on July 1, 2022. Likewise, we have a call option under which we have the right to require the Sponsors to sell their interest in the joint venture to Humana beginning on July 2, 2022 and ending on July 1, 2023. The put and call options, which are exercisable at a fixed EBITDA multiple and provide a minimum return on the Sponsor's investment if exercised, are measured at fair value each period using a Monte Carlo simulation. The simulation relies on assumptions around Kindred at Home's equity value, risk free interest rates, volatility, and the details specific to the put and call options. The final purchase price allocation resulted in approximately $1 billion being allocated to the investment and $236 million and $291 million allocated to the put and call options, respectively. The fair values of the put option and call option were $234 million and $217 million, respectively, at March 31, 2019. The put option is included within other long-term liabilities and the call option is included within other long-term assets. The change in fair value of the put and call options is reflected as "Other expense, net" in our condensed consolidated statements of income.

Health Care Reform

The Patient Protection and Affordable Care Act and The Health Care and Education Reconciliation Act of 2010 (which we collectively refer to as the Health Care Reform Law) enacted significant reforms to various aspects of the U.S. health insurance industry. Certain of these reforms became effective January 1, 2014, including an annual insurance industry premium-based fee. The Continuing Resolution bill, H.R. 195, enacted on January 22, 2018, included a one year suspension in 2019 of the health insurance industry fee, but under current law, the fee is scheduled to resume in calendar year 2020. In October 2018, we paid the federal government $1.04 billion for the annual health insurance industry fee attributed to calendar year 2018. This fee, fixed in amount by law and apportioned to insurance carriers based on market share, was not deductible for tax purposes. Each year on January 1, except when suspended, we record a liability for this fee in trade accounts payable and accrued expenses which we carry until the fee is paid. We record a corresponding deferred cost in other current assets in our condensed consolidated financial statements which is amortized ratably to expense over the calendar year. Amortization of the deferred cost was recorded in operating cost expense of approximately $263 million for the three months ended March 31, 2018, resulting from the amortization of the 2018 annual health insurance industry fee.