Divestitures	9 Months Ended
Sep. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	Divestitures On June 19, 2018, the Company sold its non-core Permian Basin assets located in Texas for net proceeds of $57.7 million, subject to final purchase price adjustments (the Permian Divestiture). The assets sold in the Permian Divestiture included approximately 970 productive wells with current net production of approximately 20 MMcfe per day, approximately 350 miles of low-pressure gathering lines and 26 compressors. On July 18, 2018, the Company sold approximately 2.5 million non-core, net acres in the Huron Play for net proceeds of $523.6 million, subject to final purchase price adjustments (the Huron Divestiture). The assets sold in the Huron Divestiture included approximately 12,000 productive wells with current net production of approximately 200 MMcfe per day, approximately 6,400 miles of low-pressure gathering lines and 59 compressor stations. The Company retained the deep drilling rights across the divested acreage. During the first quarter of 2018, the Company recorded an impairment of $2.3 billion associated with the production and related midstream assets in the Huron and Permian Plays. The impairment of these properties and related pipeline assets recorded during the first quarter of 2018 was due to the carrying value of the assets exceeding the undiscounted cash flows which were expected to result from the continued use and potential disposition of the underlying assets as well as management’s determination that it no longer intended to develop the associated unproved properties. The first quarter of 2018 impairment reduced these assets to their estimated fair value at that time of approximately $1 billion. The fair value of the impaired assets, as determined at March 31, 2018, was based on significant inputs that were not observable in the market and as such are considered to be Level 3 fair value measurements. See Note K for a description of the fair value hierarchy and Note 1 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 for our policy on impairment of proved and unproved properties. Key assumptions included in the calculation of the fair value of the impaired assets as of March 31, 2018 included (i) reserves, including risk adjustments for probable and possible reserves; (ii) future commodity prices; (iii) to the extent available, market based indicators of fair value including estimated proceeds which could be realized upon a potential disposition; (iv) production rates based on the Company's experience with similar properties in which it operates; (v) estimated future operating and development costs; and (vi) a market-based weighted average cost of capital. In connection with the Permian Divestiture and the Huron Divestiture, the Company recorded an additional impairment/loss on sale of long-lived assets of $118.1 million during the second quarter of 2018 to write down the carrying value of the disposal groups to the estimated amounts to be received upon the closing of the transactions. In connection with the closing of the Huron Divestiture, the Company recorded a loss of $259.3 million during the third quarter of 2018 related to certain capacity contracts that the Company no longer has existing production to satisfy and does not plan to utilize in the future. The loss was recorded within operating expenses under the impairment/loss on sale of long-lived assets caption within the Statements of Consolidated Operations. The fair value of the loss for the initial measurement was based upon significant inputs that were not observable in the market and as such is considered a Level 3 fair value measurement. The key unobservable input in the calculation is the amount, if any, of potential future economic benefit from the contracts.

Divestitures

On June 19, 2018, the Company sold its non-core Permian Basin assets located in Texas for net proceeds of $57.7 million, subject to final purchase price adjustments (the Permian Divestiture). The assets sold in the Permian Divestiture included approximately 970 productive wells with current net production of approximately 20 MMcfe per day, approximately 350 miles of low-pressure gathering lines and 26 compressors.

On July 18, 2018, the Company sold approximately 2.5 million non-core, net acres in the Huron Play for net proceeds of $523.6 million, subject to final purchase price adjustments (the Huron Divestiture). The assets sold in the Huron Divestiture included approximately 12,000 productive wells with current net production of approximately 200 MMcfe per day, approximately 6,400 miles of low-pressure gathering lines and 59 compressor stations. The Company retained the deep drilling rights across the divested acreage.

During the first quarter of 2018, the Company recorded an impairment of $2.3 billion associated with the production and related midstream assets in the Huron and Permian Plays. The impairment of these properties and related pipeline assets recorded during the first quarter of 2018 was due to the carrying value of the assets exceeding the undiscounted cash flows which were expected to result from the continued use and potential disposition of the underlying assets as well as management’s determination that it no longer intended to develop the associated unproved properties. The first quarter of 2018 impairment reduced these assets to their estimated fair value at that time of approximately $1 billion.

The fair value of the impaired assets, as determined at March 31, 2018, was based on significant inputs that were not observable in the market and as such are considered to be Level 3 fair value measurements. See Note K for a description of the fair value hierarchy and Note 1 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 for our policy on impairment of proved and unproved properties. Key assumptions included in the calculation of the fair value of the impaired assets as of March 31, 2018 included (i) reserves, including risk adjustments for probable and possible reserves; (ii) future commodity prices; (iii) to the extent available, market based indicators of fair value including estimated proceeds which could be realized upon a potential disposition; (iv) production rates based on the Company's experience with similar properties in which it operates; (v) estimated future operating and development costs; and (vi) a market-based weighted average cost of capital.

In connection with the Permian Divestiture and the Huron Divestiture, the Company recorded an additional impairment/loss on sale of long-lived assets of $118.1 million during the second quarter of 2018 to write down the carrying value of the disposal groups to the estimated amounts to be received upon the closing of the transactions.

In connection with the closing of the Huron Divestiture, the Company recorded a loss of $259.3 million during the third quarter of 2018 related to certain capacity contracts that the Company no longer has existing production to satisfy and does not plan to utilize in the future. The loss was recorded within operating expenses under the impairment/loss on sale of long-lived assets caption within the Statements of Consolidated Operations.

The fair value of the loss for the initial measurement was based upon significant inputs that were not observable in the market and as such is considered a Level 3 fair value measurement. The key unobservable input in the calculation is the amount, if any, of potential future economic benefit from the contracts.