Loss on Impairment	12 Months Ended
Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Loss on Impairment	Note 11 - Loss on Impairment Asset impairments In connection with the preparation of the consolidated financial statements included in this Annual Report, consistent with our accounting policies discussed in Note 1, we evaluate our drilling fleet assets for impairment on an annual basis or whenever there are changes in facts which suggest that the value of the asset is not recoverable. In the fourth quarter of 2015, in connection with our annual impairment analysis, we decided that we would no longer market one of our drillships, the Noble Discoverer. The decision was a result of the termination of the contract for this rig by Shell in December 2015 and the decreased opportunities for rigs of this type in the current marketplace. We also reviewed assumptions on the future marketability of one of our jackups, the Noble Charles Copeland, after its contract completion in late September 2015, with consideration given to its years in service, limited technical features and anticipated capital requirements in light of the current market conditions. As a result of this analysis, we have decided to discontinue marketing this unit. Additionally, as a result of a fourth quarter review of capital spare equipment, we elected to retire certain capital spare equipment. We evaluated these units and certain capital spare equipment for impairment and recorded an impairment charge of $406 million for the year ended December 31, 2015. Also in 2015, we determined that certain corporate assets were partially impaired due to a declining market for, and the potential disposal of, the assets. We estimated the fair value of the assets based on quotes from brokers of similar assets (Level 2). Based on these estimates, we recorded an impairment charge of approximately $13 million for the year ended December 31, 2015. During the fourth quarter of 2014, we reviewed assumptions on the future marketability of the Noble Driller, the Noble Jim Thompson and the Noble Paul Wolff with consideration given to their years in service, limited technical features and anticipated capital requirements in light of the market conditions and decided to discontinue marketing these units. We evaluated these units for impairment and recorded an impairment charge of approximately $685 million on these rigs for the year ended December 31, 2014. The total remaining book value of $47 million at December 31, 2014 represented the equipment present on the rigs, which was available for redeployment within our fleet. The remaining book value was a Level 3 fair value measurement under accounting literature as it contained significant estimation and non-observable inputs. In 2012, we determined that our submersible rig fleet, consisting of two cold stacked rigs, was partially impaired due to the declining market outlook for drilling services for that rig type. We estimated the fair value of the rigs based on the salvage value of the rigs and a then recent transaction involving a similar unit owned by a peer company (Level 2 fair value measurement). Based on these estimates, we recognized an impairment charge of approximately $13 million for the year ended December 31, 2012. During 2013, we recorded an additional impairment charge of approximately $4 million on these rigs arising from the potential disposition of these assets to an unrelated third party. In January 2014, we completed the sale of the submersibles for a total sales price of $7 million. Goodwill In connection with our acquisition of FDR Holdings Limited (“Frontier”) in 2010, we recognized goodwill in our Contract Drilling Services reporting unit. In connection with the preparation of the consolidated financial statements included in this Annual Report, as discussed in Note 1, we conduct goodwill impairment testing annually in the fourth quarter of each year and when events occur that would potentially reduce the fair value of our reporting unit below its carrying amount. As part of our annual test completed in 2014, we noted a significant decline in the market value of our stock, coupled with a decrease in oil and gas prices, significant reductions in the projected dayrates for new contracts and reduced utilization forecasts. These factors drove our fair value of the reporting unit below the book value, and we concluded that the goodwill in the Contract Drilling Services reporting unit was impaired. We deemed this to be a Level 3 fair value measurement under accounting literature as it contains significant estimation and non-observable inputs. During 2014, we fully impaired the $60 million of goodwill.

Note 11 - Loss on Impairment

Asset impairments

In connection with the preparation of the consolidated financial statements included in this Annual Report, consistent with our accounting policies discussed in Note 1, we evaluate our drilling fleet assets for impairment on an annual basis or whenever there are changes in facts which suggest that the value of the asset is not recoverable.

In the fourth quarter of 2015, in connection with our annual impairment analysis, we decided that we would no longer market one of our drillships, the Noble Discoverer. The decision was a result of the termination of the contract for this rig by Shell in December 2015 and the decreased opportunities for rigs of this type in the current marketplace. We also reviewed assumptions on the future marketability of one of our jackups, the Noble Charles Copeland, after its contract completion in late September 2015, with consideration given to its years in service, limited technical features and anticipated capital requirements in light of the current market conditions. As a result of this analysis, we have decided to discontinue marketing this unit. Additionally, as a result of a fourth quarter review of capital spare equipment, we elected to retire certain capital spare equipment. We evaluated these units and certain capital spare equipment for impairment and recorded an impairment charge of $406 million for the year ended December 31, 2015.

Also in 2015, we determined that certain corporate assets were partially impaired due to a declining market for, and the potential disposal of, the assets. We estimated the fair value of the assets based on quotes from brokers of similar assets (Level 2). Based on these estimates, we recorded an impairment charge of approximately $13 million for the year ended December 31, 2015.

During the fourth quarter of 2014, we reviewed assumptions on the future marketability of the Noble Driller, the Noble Jim Thompson and the Noble Paul Wolff with consideration given to their years in service, limited technical features and anticipated capital requirements in light of the market conditions and decided to discontinue marketing these units. We evaluated these units for impairment and recorded an impairment charge of approximately $685 million on these rigs for the year ended December 31, 2014. The total remaining book value of $47 million at December 31, 2014 represented the equipment present on the rigs, which was available for redeployment within our fleet. The remaining book value was a Level 3 fair value measurement under accounting literature as it contained significant estimation and non-observable inputs.

In 2012, we determined that our submersible rig fleet, consisting of two cold stacked rigs, was partially impaired due to the declining market outlook for drilling services for that rig type. We estimated the fair value of the rigs based on the salvage value of the rigs and a then recent transaction involving a similar unit owned by a peer company (Level 2 fair value measurement). Based on these estimates, we recognized an impairment charge of approximately $13 million for the year ended December 31, 2012. During 2013, we recorded an additional impairment charge of approximately $4 million on these rigs arising from the potential disposition of these assets to an unrelated third party. In January 2014, we completed the sale of the submersibles for a total sales price of $7 million.

Goodwill

In connection with our acquisition of FDR Holdings Limited (“Frontier”) in 2010, we recognized goodwill in our Contract Drilling Services reporting unit. In connection with the preparation of the consolidated financial statements included in this Annual Report, as discussed in Note 1, we conduct goodwill impairment testing annually in the fourth quarter of each year and when events occur that would potentially reduce the fair value of our reporting unit below its carrying amount.

As part of our annual test completed in 2014, we noted a significant decline in the market value of our stock, coupled with a decrease in oil and gas prices, significant reductions in the projected dayrates for new contracts and reduced utilization forecasts. These factors drove our fair value of the reporting unit below the book value, and we concluded that the goodwill in the Contract Drilling Services reporting unit was impaired. We deemed this to be a Level 3 fair value measurement under accounting literature as it contains significant estimation and non-observable inputs. During 2014, we fully impaired the $60 million of goodwill.