Impairment (Notes)	6 Months Ended
Jun. 30, 2015
Asset Impairment Charges [Abstract]
Impairment	Impairment Impairment of Long-Lived Assets On a quarterly basis, we evaluate the carrying value of our property and equipment to identify events or changes in circumstances ("triggering events") that indicate the carrying value may not be recoverable. During the second quarter, we concluded that a triggering event had occurred on several rigs due to contract concessions and performed an asset impairment analysis. Based on the analysis performed, we concluded the carrying values of these rigs were recoverable. We continue to have ongoing discussions with certain customers requesting contract concessions. The outcome of these negotiations remains uncertain; however, deterioration of existing contract terms and/or change in our long-term operating assumptions resulting from these negotiations could lead to a material impairment charge in future periods. During the second quarter of 2014, demand for floaters deteriorated as a result of continued reduction in capital spending by customers in addition to delays in customers’ drilling programs. The reduction in demand, combined with the increasing supply from newbuild floater deliveries, led to a very competitive market. In general, contracting activity for floaters declined significantly, and new day rate fixtures were substantially lower than rates previously realized. In response to the adverse change in the floaters business climate, management evaluated our older, less capable floaters and committed to a plan to sell five rigs. ENSCO 5000, ENSCO 5001, ENSCO 5002, ENSCO 6000 and ENSCO 7500 were removed from our portfolio of rigs marketed for contract drilling services and actively marketed for sale. These rigs were written down to fair value, less costs to sell, as of May 31, 2014 and classified as "held for sale." We completed the sale of ENSCO 5000 during the fourth quarter of 2014 and ENSCO 5002 during the second quarter of 2015. The remaining three floaters were classified as "held for sale" on our June 30, 2015 condensed consolidated balance sheet. We measured the fair value of the "held for sale" rigs by applying a market approach, which was based on unobservable third-party estimated prices that would be received in exchange for the assets in an orderly transaction between market participants. We recorded a pre-tax, non-cash loss on impairment totaling $546.4 million during the three-month and six-month periods ended June 30, 2014. The impairment charge was included in loss from discontinued operations, net in our condensed consolidated statement of operations for the three-month and six-month periods ended June 30, 2014. See "Note 9 - Discontinued Operations" for additional information on our "held for sale" rigs. As a result of the adverse change in the floater business climate observed during the second quarter of 2014, management's commitment to a plan to sell five floaters during the second quarter of 2014 and the impairment charge incurred on the "held for sale" floaters, management concluded that a triggering event had occurred during the second quarter of 2014 and performed an asset impairment analysis on our remaining older, less capable floaters. Based on the analysis performed as of May 31, 2014, we recorded an additional non-cash loss on impairment with respect to four other floaters totaling $991.5 million, of which $288.0 million related to ENSCO DS-2 which was removed from our portfolio of rigs marketed for contract drilling services during the fourth quarter of 2014. As a result, the ENSCO DS-2 impairment charge was reclassified to loss from discontinued operations, net in our condensed consolidated statement of operations for the three-month and six-month periods ended June 30, 2014. The remaining $703.5 million impairment charge was included in loss on impairment in our condensed consolidated statement of operations for the three-month and six-month periods ended June 30, 2014. We measured the fair value of these rigs by applying an income approach, using projected discounted cash flows. These valuations were based on unobservable inputs that require significant judgments for which there is limited information, including assumptions regarding future day rates, utilization, operating costs and capital requirements.

Impairment

Impairment of Long-Lived Assets

On a quarterly basis, we evaluate the carrying value of our property and equipment to identify events or changes in circumstances ("triggering events") that indicate the carrying value may not be recoverable. During the second quarter, we concluded that a triggering event had occurred on several rigs due to contract concessions and performed an asset impairment analysis. Based on the analysis performed, we concluded the carrying values of these rigs were recoverable. We continue to have ongoing discussions with certain customers requesting contract concessions. The outcome of these negotiations remains uncertain; however, deterioration of existing contract terms and/or change in our long-term operating assumptions resulting from these negotiations could lead to a material impairment charge in future periods.

During the second quarter of 2014, demand for floaters deteriorated as a result of continued reduction in capital spending by customers in addition to delays in customers’ drilling programs. The reduction in demand, combined with the increasing supply from newbuild floater deliveries, led to a very competitive market. In general, contracting activity for floaters declined significantly, and new day rate fixtures were substantially lower than rates previously realized. In response to the adverse change in the floaters business climate, management evaluated our older, less capable floaters and committed to a plan to sell five rigs. ENSCO 5000, ENSCO 5001, ENSCO 5002, ENSCO 6000 and ENSCO 7500 were removed from our portfolio of rigs marketed for contract drilling services and actively marketed for sale. These rigs were written down to fair value, less costs to sell, as of May 31, 2014 and classified as "held for sale." We completed the sale of ENSCO 5000 during the fourth quarter of 2014 and ENSCO 5002 during the second quarter of 2015. The remaining three floaters were classified as "held for sale" on our June 30, 2015 condensed consolidated balance sheet.

We measured the fair value of the "held for sale" rigs by applying a market approach, which was based on unobservable third-party estimated prices that would be received in exchange for the assets in an orderly transaction between market participants. We recorded a pre-tax, non-cash loss on impairment totaling $546.4 million during the three-month and six-month periods ended June 30, 2014. The impairment charge was included in loss from discontinued operations, net in our condensed consolidated statement of operations for the three-month and six-month periods ended June 30, 2014. See "Note 9 - Discontinued Operations" for additional information on our "held for sale" rigs.

As a result of the adverse change in the floater business climate observed during the second quarter of 2014, management's commitment to a plan to sell five floaters during the second quarter of 2014 and the impairment charge incurred on the "held for sale" floaters, management concluded that a triggering event had occurred during the second quarter of 2014 and performed an asset impairment analysis on our remaining older, less capable floaters.

Based on the analysis performed as of May 31, 2014, we recorded an additional non-cash loss on impairment with respect to four other floaters totaling $991.5 million, of which $288.0 million related to ENSCO DS-2 which was removed from our portfolio of rigs marketed for contract drilling services during the fourth quarter of 2014. As a result, the ENSCO DS-2 impairment charge was reclassified to loss from discontinued operations, net in our condensed consolidated statement of operations for the three-month and six-month periods ended June 30, 2014. The remaining $703.5 million impairment charge was included in loss on impairment in our condensed consolidated statement of operations for the three-month and six-month periods ended June 30, 2014. We measured the fair value of these rigs by applying an income approach, using projected discounted cash flows. These valuations were based on unobservable inputs that require significant judgments for which there is limited information, including assumptions regarding future day rates, utilization, operating costs and capital requirements.