| **Commitments and Contingencies**                       | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
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| **Commitments and Contingencies Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Commitments and Contingencies                           |  Commitments and Contingencies CONSOL Carried Cost Obligation   In accordance with our Marcellus Shale joint venture arrangement with a subsidiary of CONSOL Energy Inc. (CONSOL), we agreed to fund one-third of CONSOL's 50% working interest share of future drilling and completion costs, capped at $400 million each year, up to approximately $2.1 billion (CONSOL Carried Cost Obligation). The CONSOL Carried Cost Obligation is suspended if average Henry Hub natural gas prices fall and remain below $4.00 per MMBtu in any three consecutive month period and remain suspended until average Henry Hub natural gas prices are above $4.00 per MMBtu for three consecutive months. Due to low natural gas prices, the CONSOL Carried Cost Obligation was suspended from the end of 2011 until February 28, 2014. Due to recent increases in Henry Hub natural gas prices, we began funding a portion of CONSOL's working interest share of certain drilling and completion costs as of March 1, 2014. Based on the June 30, 2014 NYMEX Henry Hub natural gas price curve and current development plans, we forecast we will incur approximately $240 million under the CONSOL Carried Cost Obligation for the year ended December 31, 2014.Marcellus Shale Firm Transportation Agreements   In February 2014, we signed Precedent Agreements for Firm Transportation (the Agreements) to flow 150,000 MMBtu per day of our Marcellus Shale natural gas production to Gulf Coast markets. The Agreements, which are expected to be executed in the second half of 2014, are for transportation services on new pipeline extensions, to be constructed by, and connecting to, an existing third-party system. The pipeline extensions are expected to be complete and operational in June of 2017. Our financial commitment totals approximately $765 million, undiscounted, over a 15-year period. The Agreements are subject to various conditions, including regulatory approval of the pipeline extension projects. Legal Proceedings  We are involved in various legal proceedings in the ordinary course of business.  These proceedings are subject to the uncertainties inherent in any litigation.  We are defending ourselves vigorously in all such matters and we believe that the ultimate disposition of such proceedings will not have a material adverse effect on our financial position, results of operations or cash flows. |

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The entire disclosure for commitments and contingencies.
+ References
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