Subsequent Event	6 Months Ended
Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Event	Note 17 ― Subsequent Event Proposed Merger On July 23, 2015, the Company entered into an Agreement and Plan of Merger (the “Agreement”) among the Company, Anthem, Inc. (“Anthem”) and Anthem Merger Sub Corp. (“Merger Sub”), a direct wholly owned subsidiary of Anthem. The Agreement provides (a) for the merger of the Company and Merger Sub, with the Company continuing as the surviving corporation and (b) if certain tax opinions relating to the qualification of the transaction under Section 368(a) of the Internal Revenue Code of 1986, as amended, are delivered, immediately following the consummation of the initial merger, for the surviving corporation to be merged with and into Anthem, with Anthem as the surviving corporation (collectively, the “Merger”). Subject to the terms, conditions and carve outs contained in the Agreement, each share of Cigna common stock issued and outstanding immediately prior to the effective time of the Merger will be converted into the right to receive (a) $103.40 in cash, without interest, and (b) 0.5152 of a share of Anthem common stock. Consummation of the Merger is subject to certain customary conditions, including approval by both Cigna and Anthem shareholders, the receipt of certain necessary governmental and regulatory approvals, and the absence of a legal restraint prohibiting the consummation of the Merger. Consummation of the Merger is not subject to a financing condition. The Agreement further provides that, upon termination under certain circumstances, including one party entering into a binding agreement for a superior proposal or due to a change in the board of director's recommendation, such party may be required to pay to the other party a termination fee of $1.85 billion. In the event that the Agreement is terminated by either Anthem or Cigna if (a) a regulatory restraint preventing the Merger has become final or non-appealable or (b) the Merger has not been consummated on or prior to January 31, 2017 (subject to extension to April 30, 2017 under certain circumstances) and at the time of such termination, the conditions to Anthem's obligation to consummate the Merger have been satisfied other than those that relate to a regulatory restraint or a regulatory approval, Cigna will be entitled to receive from Anthem a reverse termination fee of $1.85 billion. If the Merger Agreement is terminated because the shareholders of either company fail to approve the transaction, that company must pay $600 million to the other party. The transaction is expected to close in the latter half of 2016.

Subsequent Event

6 Months Ended

Jun. 30, 2015

Note 17 ― Subsequent Event

Proposed Merger

On July 23, 2015, the Company entered into an Agreement and Plan of Merger (the “Agreement”) among the Company, Anthem, Inc. (“Anthem”) and Anthem Merger Sub Corp. (“Merger Sub”), a direct wholly owned subsidiary of Anthem. The Agreement provides (a) for the merger of the Company and Merger Sub, with the Company continuing as the surviving corporation and (b) if certain tax opinions relating to the qualification of the transaction under Section 368(a) of the Internal Revenue Code of 1986, as amended, are delivered, immediately following the consummation of the initial merger, for the surviving corporation to be merged with and into Anthem, with Anthem as the surviving corporation (collectively, the “Merger”). Subject to the terms, conditions and carve outs contained in the Agreement, each share of Cigna common stock issued and outstanding immediately prior to the effective time of the Merger will be converted into the right to receive (a) $103.40 in cash, without interest, and (b) 0.5152 of a share of Anthem common stock.

Consummation of the Merger is subject to certain customary conditions, including approval by both Cigna and Anthem shareholders, the receipt of certain necessary governmental and regulatory approvals, and the absence of a legal restraint prohibiting the consummation of the Merger. Consummation of the Merger is not subject to a financing condition.

The Agreement further provides that, upon termination under certain circumstances, including one party entering into a binding agreement for a superior proposal or due to a change in the board of director's recommendation, such party may be required to pay to the other party a termination fee of $1.85 billion. In the event that the Agreement is terminated by either Anthem or Cigna if (a) a regulatory restraint preventing the Merger has become final or non-appealable or (b) the Merger has not been consummated on or prior to January 31, 2017 (subject to extension to April 30, 2017 under certain circumstances) and at the time of such termination, the conditions to Anthem's obligation to consummate the Merger have been satisfied other than those that relate to a regulatory restraint or a regulatory approval, Cigna will be entitled to receive from Anthem a reverse termination fee of $1.85 billion. If the Merger Agreement is terminated because the shareholders of either company fail to approve the transaction, that company must pay $600 million to the other party.

The transaction is expected to close in the latter half of 2016.