Basis of Presentation and Significant Events	9 Months Ended
Sep. 30, 2015
Basis of Presentation [Abstract]
Basis of Accounting and Significant Events [Text Block]	BASIS OF PRESENTATION AND SIGNIFICANT EVENTS Basis of Presentation Health Net, Inc. prepared the accompanying unaudited consolidated financial statements following the rules and regulations of the U.S. Securities and Exchange Commission ("SEC") for interim reporting. In this Quarterly Report on Form 10-Q, unless the context otherwise requires, the terms “Company,” “Health Net,” “we,” “us,” and “our” refer to Health Net, Inc. and its subsidiaries. As permitted under those rules and regulations, certain notes or other financial information that are normally required by accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted if they substantially duplicate the disclosures contained in the annual audited financial statements. The accompanying unaudited consolidated financial statements should be read together with the audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2014 ("Form 10-K"). We are responsible for the accompanying unaudited consolidated financial statements. These consolidated financial statements include all normal and recurring adjustments that are considered necessary for the fair presentation of our financial position and operating results in accordance with GAAP. In accordance with GAAP, we make certain estimates and assumptions that affect the reported amounts. Actual results could differ from those estimates and assumptions. In addition, revenues, expenses, assets and liabilities can vary during each quarter of the year. Therefore, the results and trends in these interim financial statements may not be indicative of those for the full year. Significant Events Pending Merger On July 2, 2015, the Company entered into an Agreement and Plan of Merger (the "Merger Agreement") with Centene Corporation, a Delaware corporation ("Centene"), together with Chopin Merger Sub I, Inc. ("Merger Sub I") and Chopin Merger Sub II, Inc. ("Merger Sub II"), each a Delaware corporation and a direct, wholly-owned subsidiary of Centene. Upon the terms and subject to the conditions set forth in the Merger Agreement, (i) Merger Sub I will merge with and into the Company (the "Merger"), with the Company as the surviving corporation (the "Surviving Corporation") and (ii) subject to delivery of a legal opinion from counsel to the Surviving Corporation regarding certain aspects of the tax treatment of the transactions, immediately after the consummation of the Merger, the Surviving Corporation will merge with and into Merger Sub II, with Merger Sub II continuing as the surviving company. At the effective time of the Merger, the Company's existing stockholders will receive per share merger consideration consisting of $28.25 in cash and 0.6220 of one share of Centene's common stock. The Company and Centene each have agreed, subject to certain exceptions, not to directly or indirectly solicit competing acquisition proposals or to enter into, continue or participate in discussions or negotiations concerning, or enter into any letter of intent, memorandum of understanding, merger agreement or other agreement relating to, an alternative business combination. The completion of the Merger is subject to the satisfaction or waiver of customary closing conditions, including, without limitation, certain approval, notice or similar requirements with applicable regulatory authorities. On August 11, 2015, the Antitrust Division of the Department of Justice and the Federal Trade Commission granted early termination of the waiting period under the Hart-Scott Rodino Antitrust Improvements Act of 1976, as amended (the "HSR Act"). On October 23, 2015, our stockholders approved the adoption of the Merger Agreement and Centene’s stockholders approved the issuance of the shares of its common stock forming part of the merger consideration. The completion of the Merger is not conditioned on receipt of financing by Centene. The Merger is expected to close in early 2016, subject to the receipt of required regulatory approvals and satisfaction or waiver of other closing conditions. Cognizant Transaction On November 2, 2014, we entered into a master services agreement (as subsequently amended and restated, the "Master Services Agreement") with Cognizant Healthcare Services, LLC to provide certain services to us. In connection with the Master Services Agreement, we also entered into an asset purchase agreement (the "Asset Purchase Agreement") pursuant to which we agreed to sell certain software assets and related intellectual property we own to Cognizant (the "Asset Sale," and together with the transactions contemplated by the Master Services Agreement, the "Cognizant Transaction"). The closing of the Cognizant Transaction and commencement of services under the Master Services Agreement on the BPaaS Services Commencement Date (as defined in the Master Services Agreement), was subject to receipt of required regulatory approvals, and the closing of the related Asset Sale was scheduled for the BPaaS Services Commencement Date. However, in connection with the announcement of the Merger with Centene, we agreed with Cognizant to suspend efforts toward, and defer the occurrence of, the BPaaS Services Commencement Date to provide time for Health Net and Centene to work towards closing the Merger, and accordingly entered into an amendment to the Master Services Agreement on July 1, 2015 (the "Cognizant Amendment"). The decision to suspend efforts toward the BPaaS Services Commencement Date has similarly deferred the Asset Sale. As of December 31, 2014 we had classified $50.0 million, at fair value less cost to sell, in assets as assets held for sale. During the three months ended September 30, 2015, we reclassified assets held for sale to property and equipment held-for use and resumed depreciation of such assets due to the deferral of the Asset Sale. As of September 30, 2015, we had no assets held for sale. See Note 3 for additional information about our agreement with Cognizant, the assets previously held for sale and our subsequent amendment to the Master Services Agreement.

BASIS OF PRESENTATION AND SIGNIFICANT EVENTS

Basis of Presentation

Health Net, Inc. prepared the accompanying unaudited consolidated financial statements following the rules and regulations of the U.S. Securities and Exchange Commission ("SEC") for interim reporting. In this Quarterly Report on Form 10-Q, unless the context otherwise requires, the terms “Company,” “Health Net,” “we,” “us,” and “our” refer to Health Net, Inc. and its subsidiaries. As permitted under those rules and regulations, certain notes or other financial information that are normally required by accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted if they substantially duplicate the disclosures contained in the annual audited financial statements. The accompanying unaudited consolidated financial statements should be read together with the audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2014 ("Form 10-K").

We are responsible for the accompanying unaudited consolidated financial statements. These consolidated financial statements include all normal and recurring adjustments that are considered necessary for the fair presentation of our financial position and operating results in accordance with GAAP. In accordance with GAAP, we make certain estimates and assumptions that affect the reported amounts. Actual results could differ from those estimates and assumptions. In addition, revenues, expenses, assets and liabilities can vary during each quarter of the year. Therefore, the results and trends in these interim financial statements may not be indicative of those for the full year.

Significant Events

Pending Merger

On July 2, 2015, the Company entered into an Agreement and Plan of Merger (the "Merger Agreement") with Centene Corporation, a Delaware corporation ("Centene"), together with Chopin Merger Sub I, Inc. ("Merger Sub I") and Chopin Merger Sub II, Inc. ("Merger Sub II"), each a Delaware corporation and a direct, wholly-owned subsidiary of Centene. Upon the terms and subject to the conditions set forth in the Merger Agreement, (i) Merger Sub I will merge with and into the Company (the "Merger"), with the Company as the surviving corporation (the "Surviving Corporation") and (ii) subject to delivery of a legal opinion from counsel to the Surviving Corporation regarding certain aspects of the tax treatment of the transactions, immediately after the consummation of the Merger, the Surviving Corporation will merge with and into Merger Sub II, with Merger Sub II continuing as the surviving company.

At the effective time of the Merger, the Company's existing stockholders will receive per share merger consideration consisting of $28.25 in cash and 0.6220 of one share of Centene's common stock.

The Company and Centene each have agreed, subject to certain exceptions, not to directly or indirectly solicit competing acquisition proposals or to enter into, continue or participate in discussions or negotiations concerning, or enter into any letter of intent, memorandum of understanding, merger agreement or other agreement relating to, an alternative business combination.

The completion of the Merger is subject to the satisfaction or waiver of customary closing conditions, including, without limitation, certain approval, notice or similar requirements with applicable regulatory authorities. On August 11, 2015, the Antitrust Division of the Department of Justice and the Federal Trade Commission granted early termination of the waiting period under the Hart-Scott Rodino Antitrust Improvements Act of 1976, as amended (the "HSR Act"). On October 23, 2015, our stockholders approved the adoption of the Merger Agreement and Centene’s stockholders approved the issuance of the shares of its common stock forming part of the merger consideration.

The completion of the Merger is not conditioned on receipt of financing by Centene. The Merger is expected to close in early 2016, subject to the receipt of required regulatory approvals and satisfaction or waiver of other closing conditions.

Cognizant Transaction

On November 2, 2014, we entered into a master services agreement (as subsequently amended and restated, the "Master Services Agreement") with Cognizant Healthcare Services, LLC to provide certain services to us. In connection with the Master Services Agreement, we also entered into an asset purchase agreement (the "Asset Purchase Agreement") pursuant to which we agreed to sell certain software assets and related intellectual property we own to Cognizant (the "Asset Sale," and together with the transactions contemplated by the Master Services Agreement, the "Cognizant Transaction"). The closing of the Cognizant Transaction and commencement of services under the Master Services Agreement on the BPaaS Services Commencement Date (as defined in the Master Services Agreement), was subject to receipt of required regulatory approvals, and the closing of the related Asset Sale was scheduled for the BPaaS Services Commencement Date. However, in connection with the announcement of the Merger with Centene, we agreed with Cognizant to suspend efforts toward, and defer the occurrence of, the BPaaS Services Commencement Date to provide time for Health Net and Centene to work towards closing the Merger, and accordingly entered into an amendment to the Master Services Agreement on July 1, 2015 (the "Cognizant Amendment"). The decision to suspend efforts toward the BPaaS Services Commencement Date has similarly deferred the Asset Sale.

As of December 31, 2014 we had classified $50.0 million, at fair value less cost to sell, in assets as assets held for sale. During the three months ended September 30, 2015, we reclassified assets held for sale to property and equipment held-for use and resumed depreciation of such assets due to the deferral of the Asset Sale. As of September 30, 2015, we had no assets held for sale. See Note 3 for additional information about our agreement with Cognizant, the assets previously held for sale and our subsequent amendment to the Master Services Agreement.