BASIS OF PRESENTATION AND SIGNIFICANT EVENTS	9 Months Ended
Sep. 30, 2017
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, 2016, that was filed with the Securities and Exchange Commission, or the SEC, on February 17, 2017. We refer to the Form 10-K as the “2016 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, future policy 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 2016 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. Sale of Closed Block of Commercial Long-Term Care Insurance Business On November 6, 2017, we entered into a definitive agreement to sell the stock of our wholly-owned subsidiary, KMG America Corporation, or KMG, to Continental General Insurance Company, or CGIC, a Texas-based insurance company wholly owned by HC2 Holdings, Inc., a diversified holding company. KMG’s subsidiary, Kanawha Insurance Company, or KIC, includes our closed block of non-strategic commercial long-term care insurance policies. Based on the terms of the definitive agreement we expect to record a net loss associated with the sale of KMG of approximately $400 million. The estimated loss includes a pretax loss of approximately $900 million, offset by the expected tax benefit of approximately $500 million. We will fund the transaction with approximately $203 million of parent company cash contributed into KMG, subject to customary adjustments, in addition to the transfer of approximately$150 million of statutory capital with the sale, which together should be more than offset by the estimated $500 million cash savings associated with the expected tax treatment of the sale. The KMG transaction is anticipated to close by the third quarter of 2018 subject to customary closing conditions, including South Carolina Department of Insurance approval. There can be no assurance we will obtain regulatory approvals needed to sell the business or do so under terms acceptable to us. Workforce Optimization During the third quarter of 2017, we initiated a voluntary early retirement program and an involuntary workforce reduction program. These programs are expected to impact approximately 2,700 associates, or 5.7%, of our workforce. As a result, we recorded estimated charges of $124 million, or $0.54 per diluted common share. At October 31, 2017, we had approximately 47,200 employees. The estimated charges were recorded at the corporate level and not allocated to the segments. This charge is included with operating costs in the condensed consolidated statements of income for the three and nine month periods ended September 30, 2017. Payments under these programs are made upon termination during the early retirement or severance pay period, primarily starting as of the beginning of the first quarter of 2018. We expect this liability to be primarily paid within the next 12 months and classified it as a current liability, included in trade accounts payable and accrued expenses. Aetna Merger On July 2, 2015, we entered into an Agreement and Plan of Merger, which we refer to in this report as the Merger Agreement, with Aetna Inc. and certain wholly owned subsidiaries of Aetna Inc., which we refer to collectively as Aetna, which set forth the terms and conditions under which we agreed to merge with, and become a wholly owned subsidiary of Aetna, a transaction we refer to in this report as the Merger. The Merger was subject to customary closing conditions, including, among other things, (i) the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the receipt of necessary approvals under state insurance and healthcare laws and regulations and pursuant to certain licenses of certain of Humana’s subsidiaries, and (ii) the absence of legal restraints and prohibitions on the consummation of the Merger. On July 21, 2016, the U.S. Department of Justice and the attorneys general of certain U.S. jurisdictions filed a civil antitrust complaint in the U.S. District Court for the District of Columbia against us and Aetna, alleging that the Merger would violate Section 7 of the Clayton Antitrust Act and seeking a permanent injunction to prevent the Merger from being completed. On January 23, 2017, the Court ruled in favor of the DOJ and granted a permanent injunction of the proposed transaction. On February 14, 2017, we and Aetna agreed to mutually terminate the Merger Agreement, as our Board determined that an appeal of the Court's ruling would not be in the best interest of our stockholders. On February 16, 2017, under the terms of the Merger Agreement, we received a breakup fee of $1 billion from Aetna, which is included in our condensed consolidated statement of income in the line captioned Merger termination fee and related costs, net. Prior period Merger related transaction costs, previously included in operating costs, have been reclassified to conform to the 2017 presentation. Business Segment Reclassifications During the three months ended March 31, 2017, we realigned certain of our businesses among our reportable segments to correspond with internal management reporting changes and our previously announced planned exit from the Individual Commercial medical business on January 1, 2018. Additionally, we renamed our Group segment to the Group and Specialty segment, and began presenting the Individual Commercial business results as a separate segment rather than as part of the Retail segment. Specialty health insurance benefits, including dental, vision, other supplement health, and financial protection products, marketed to individuals are now included in the Group and Specialty segment. Specialty health insurance benefits marketed to employer groups continue to be included in the Group and Specialty segment. As a result of this realignment, our reportable segments now include Retail, Group and Specialty, Healthcare Services, and Individual Commercial. Prior period segment financial information has been recast to conform to the 2017 presentation. See Note 15 for segment financial information.

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, 2016, that was filed with the Securities and Exchange Commission, or the SEC, on February 17, 2017. We refer to the Form 10-K as the “2016 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, future policy 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 2016 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.

Sale of Closed Block of Commercial Long-Term Care Insurance Business

On November 6, 2017, we entered into a definitive agreement to sell the stock of our wholly-owned subsidiary, KMG America Corporation, or KMG, to Continental General Insurance Company, or CGIC, a Texas-based insurance company wholly owned by HC2 Holdings, Inc., a diversified holding company. KMG’s subsidiary, Kanawha Insurance Company, or KIC, includes our closed block of non-strategic commercial long-term care insurance policies. Based on the terms of the definitive agreement we expect to record a net loss associated with the sale of KMG of approximately $400 million. The estimated loss includes a pretax loss of approximately $900 million, offset by the expected tax benefit of approximately $500 million. We will fund the transaction with approximately $203 million of parent company cash contributed into KMG, subject to customary adjustments, in addition to the transfer of approximately$150 million of statutory capital with the sale, which together should be more than offset by the estimated $500 million cash savings associated with the expected tax treatment of the sale. The KMG transaction is anticipated to close by the third quarter of 2018 subject to customary closing conditions, including South Carolina Department of Insurance approval. There can be no assurance we will obtain regulatory approvals needed to sell the business or do so under terms acceptable to us.

Workforce Optimization

During the third quarter of 2017, we initiated a voluntary early retirement program and an involuntary workforce reduction program. These programs are expected to impact approximately 2,700 associates, or 5.7%, of our workforce. As a result, we recorded estimated charges of $124 million, or $0.54 per diluted common share. At October 31, 2017, we had approximately 47,200 employees. The estimated charges were recorded at the corporate level and not allocated to the segments. This charge is included with operating costs in the condensed consolidated statements of income for the three and nine month periods ended September 30, 2017. Payments under these programs are made upon termination during the early retirement or severance pay period, primarily starting as of the beginning of the first quarter of 2018. We expect this liability to be primarily paid within the next 12 months and classified it as a current liability, included in trade accounts payable and accrued expenses.

Aetna Merger

On July 2, 2015, we entered into an Agreement and Plan of Merger, which we refer to in this report as the Merger Agreement, with Aetna Inc. and certain wholly owned subsidiaries of Aetna Inc., which we refer to collectively as Aetna, which set forth the terms and conditions under which we agreed to merge with, and become a wholly owned subsidiary of Aetna, a transaction we refer to in this report as the Merger.

The Merger was subject to customary closing conditions, including, among other things, (i) the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the receipt of necessary approvals under state insurance and healthcare laws and regulations and pursuant to certain licenses of certain of Humana’s subsidiaries, and (ii) the absence of legal restraints and prohibitions on the consummation of the Merger.

On July 21, 2016, the U.S. Department of Justice and the attorneys general of certain U.S. jurisdictions filed a civil antitrust complaint in the U.S. District Court for the District of Columbia against us and Aetna, alleging that the Merger would violate Section 7 of the Clayton Antitrust Act and seeking a permanent injunction to prevent the Merger from being completed. On January 23, 2017, the Court ruled in favor of the DOJ and granted a permanent injunction of the proposed transaction. On February 14, 2017, we and Aetna agreed to mutually terminate the Merger Agreement, as our Board determined that an appeal of the Court's ruling would not be in the best interest of our stockholders. On February 16, 2017, under the terms of the Merger Agreement, we received a breakup fee of $1 billion from Aetna, which is included in our condensed consolidated statement of income in the line captioned Merger termination fee and related costs, net. Prior period Merger related transaction costs, previously included in operating costs, have been reclassified to conform to the 2017 presentation.

Business Segment Reclassifications

During the three months ended March 31, 2017, we realigned certain of our businesses among our reportable segments to correspond with internal management reporting changes and our previously announced planned exit from the Individual Commercial medical business on January 1, 2018. Additionally, we renamed our Group segment to the Group and Specialty segment, and began presenting the Individual Commercial business results as a separate segment rather than as part of the Retail segment. Specialty health insurance benefits, including dental, vision, other supplement health, and financial protection products, marketed to individuals are now included in the Group and Specialty segment. Specialty health insurance benefits marketed to employer groups continue to be included in the Group and Specialty segment. As a result of this realignment, our reportable segments now include Retail, Group and Specialty, Healthcare Services, and Individual Commercial. Prior period segment financial information has been recast to conform to the 2017 presentation. See Note 15 for segment financial information.