Income Taxes	6 Months Ended
Jun. 30, 2011
Income Taxes
Income Taxes	Note 5 — Income Taxes Income taxes during interim periods are based on the estimated annual effective income tax rate plus any significant, unusual or infrequently occurring items that are recorded in the period the specific item occurs. We compute income taxes using an asset and liability approach, which results in the recognition of deferred tax liabilities and assets for the expected future tax consequences of temporary differences between the financial basis and the tax basis of those assets and liabilities. As of June 30, 2011 and December 31, 2010, for U.S. and Netherlands tax provision purposes, we have provided valuation allowances for the entirety of our net deferred tax assets based on our cumulative net losses coupled with the uncertainties surrounding our future earnings forecasts arising from the continued permitting delays in the Gulf of Mexico. The U.K. supplementary charge of corporation tax was increased from 20% to 32%, effective March 24, 2011. This change has not been reflected in the provision for the six months ended June 30, 2011 because it was not signed into law at that date; however, it is expected to affect U.K. results of operations once it is enacted. We recognized income tax benefit of $14.5 million and $57.8 million, respectively, for the three months ended June 30, 2011 and 2010. We recognized income tax benefit of $5.4 million and $56.4 million, respectively, for the six months ended June 30, 2011 and 2010. The worldwide effective tax rates for the three months ended June 30, 2011 and 2010 were 22.3% and 43.1%, respectively. The worldwide effective tax rates for the six months ended June 30, 2011 and 2010 were 3.2% and 44.6%, respectively.

Income Taxes

6 Months Ended

Jun. 30, 2011

Note 5 — Income Taxes

Income taxes during interim periods are based on the estimated annual effective income tax rate plus any significant, unusual or infrequently occurring items that are recorded in the period the specific item occurs. We compute income taxes using an asset and liability approach, which results in the recognition of deferred tax liabilities and assets for the expected future tax consequences of temporary differences between the financial basis and the tax basis of those assets and liabilities. As of June 30, 2011 and December 31, 2010, for U.S. and Netherlands tax provision purposes, we have provided valuation allowances for the entirety of our net deferred tax assets based on our cumulative net losses coupled with the uncertainties surrounding our future earnings forecasts arising from the continued permitting delays in the Gulf of Mexico. The U.K. supplementary charge of corporation tax was increased from 20% to 32%, effective March 24, 2011. This change has not been reflected in the provision for the six months ended June 30, 2011 because it was not signed into law at that date; however, it is expected to affect U.K. results of operations once it is enacted. We recognized income tax benefit of $14.5 million and $57.8 million, respectively, for the three months ended June 30, 2011 and 2010. We recognized income tax benefit of $5.4 million and $56.4 million, respectively, for the six months ended June 30, 2011 and 2010. The worldwide effective tax rates for the three months ended June 30, 2011 and 2010 were 22.3% and 43.1%, respectively. The worldwide effective tax rates for the six months ended June 30, 2011 and 2010 were 3.2% and 44.6%, respectively.