Income Taxes	9 Months Ended
Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Tax Disclosure	Income Taxes The effective tax rate was approximately 17% and 43% for the three and nine months ended September 30, 2016, respectively. The effective tax rate for the three and nine months ended September 30, 2015 was approximately 24% and 26%, respectively. The tax rates for the three and nine months ended September 30, 2016 reflect project losses in the U.S. for which we do not recognize tax benefits as well as a discrete tax benefit in the quarter related to a recovery of foreign withholding taxes previously expensed associated with a completed EPC project in Nigeria. Our estimated annual effective tax rate for 2016 is currently projected to be 52%, which is higher than the U.S. statutory rate of 35% primarily due to project losses in the U.S. for which we do not recognize tax benefits as well as forecasted income in higher tax rate jurisdictions. Our estimated annual effective rate is subject to change based on the actual jurisdictions where our 2016 earnings are generated. Our foreign subsidiaries generate earnings that are not subject to U.S. income taxes so long as they are permanently reinvested in our operations outside of the U.S. Undistributed earnings of foreign subsidiaries that are no longer permanently reinvested become subject to deferred income taxes under U.S. tax law. Prior to the third quarter of 2016, we asserted that the undistributed earnings of our foreign subsidiaries above the amount for which we had already provided income taxes continued to be considered permanently reinvested. As a result of strategic business acquisitions and previously announced estimated contract losses during the third quarter, we determined the need to reevaluate our permanent reinvestment assertion of certain undistributed foreign earnings. Likewise, we have provided cumulative income taxes of $40 million on certain foreign earnings which provide us, if necessary, the ability to repatriate an additional $300 million of international cash without recognizing additional tax expense. In determining whether the undistributed earnings of our foreign subsidiaries are permanently reinvested, we consider our future U.S. and non-U.S. cash needs such as 1) our anticipated foreign working capital requirements, including funding of our U.K. pension plan, 2) the expected growth opportunities across all geographical markets and 3) our plans to invest in strategic growth opportunities that may include acquisitions around the world. The remaining international cash balances associated with past foreign earnings which we currently consider to be permanently reinvested in our foreign entities are not available for domestic use. Our undistributed earnings above the previously established amounts for which we have already provided income taxes continue to be considered permanently reinvested in the foreseeable future. These undistributed earnings could be subject to additional tax if remitted, or deemed remitted, as a dividend. The valuation allowance for deferred tax assets as of September 30, 2016 and December 31, 2015 was $541 million and $542 million, respectively. The change in the valuation allowance was $5 million and $(48) million in the three months ended September 30, 2016 and 2015, respectively, and $(1) million and $(60) million for the nine months ended September 30, 2016 and 2015, respectively. The valuation allowance is primarily related to foreign tax credit carryforwards, foreign and state net operating loss carryforwards and other deferred tax assets that, in the judgment of management, are not more-likely-than-not to be realized. The changes in the valuation allowance for the three and nine months ended September 30, 2016 is reflective of an increase in the valuation of our foreign tax credit carryforwards primarily offset by a decrease in the valuation allowance related to deferred taxes provided on certain foreign earnings. The reserve for uncertain tax positions included in "other liabilities" and "deferred income taxes" on our condensed consolidated balance sheets as of September 30, 2016 and December 31, 2015 was $274 million and $257 million, respectively. The balance at September 30, 2016 includes a $14 million reserve for uncertain tax positions from acquisitions that occurred during the third quarter.

Income Taxes

The effective tax rate was approximately 17% and 43% for the three and nine months ended September 30, 2016, respectively. The effective tax rate for the three and nine months ended September 30, 2015 was approximately 24% and 26%, respectively. The tax rates for the three and nine months ended September 30, 2016 reflect project losses in the U.S. for which we do not recognize tax benefits as well as a discrete tax benefit in the quarter related to a recovery of foreign withholding taxes previously expensed associated with a completed EPC project in Nigeria.

Our estimated annual effective tax rate for 2016 is currently projected to be 52%, which is higher than the U.S. statutory rate of 35% primarily due to project losses in the U.S. for which we do not recognize tax benefits as well as forecasted income in higher tax rate jurisdictions. Our estimated annual effective rate is subject to change based on the actual jurisdictions where our 2016 earnings are generated.

Our foreign subsidiaries generate earnings that are not subject to U.S. income taxes so long as they are permanently reinvested in our operations outside of the U.S. Undistributed earnings of foreign subsidiaries that are no longer permanently reinvested become subject to deferred income taxes under U.S. tax law. Prior to the third quarter of 2016, we asserted that the undistributed earnings of our foreign subsidiaries above the amount for which we had already provided income taxes continued to be considered permanently reinvested. As a result of strategic business acquisitions and previously announced estimated contract losses during the third quarter, we determined the need to reevaluate our permanent reinvestment assertion of certain undistributed foreign earnings. Likewise, we have provided cumulative income taxes of $40 million on certain foreign earnings which provide us, if necessary, the ability to repatriate an additional $300 million of international cash without recognizing additional tax expense.

In determining whether the undistributed earnings of our foreign subsidiaries are permanently reinvested, we consider our future U.S. and non-U.S. cash needs such as 1) our anticipated foreign working capital requirements, including funding of our U.K. pension plan, 2) the expected growth opportunities across all geographical markets and 3) our plans to invest in strategic growth opportunities that may include acquisitions around the world. The remaining international cash balances associated with past foreign earnings which we currently consider to be permanently reinvested in our foreign entities are not available for domestic use. Our undistributed earnings above the previously established amounts for which we have already provided income taxes continue to be considered permanently reinvested in the foreseeable future. These undistributed earnings could be subject to additional tax if remitted, or deemed remitted, as a dividend.

The valuation allowance for deferred tax assets as of September 30, 2016 and December 31, 2015 was $541 million and $542 million, respectively. The change in the valuation allowance was $5 million and $(48) million in the three months ended September 30, 2016 and 2015, respectively, and $(1) million and $(60) million for the nine months ended September 30, 2016 and 2015, respectively. The valuation allowance is primarily related to foreign tax credit carryforwards, foreign and state net operating loss carryforwards and other deferred tax assets that, in the judgment of management, are not more-likely-than-not to be realized. The changes in the valuation allowance for the three and nine months ended September 30, 2016 is reflective of an increase in the valuation of our foreign tax credit carryforwards primarily offset by a decrease in the valuation allowance related to deferred taxes provided on certain foreign earnings.

The reserve for uncertain tax positions included in "other liabilities" and "deferred income taxes" on our condensed consolidated balance sheets as of September 30, 2016 and December 31, 2015 was $274 million and $257 million, respectively. The balance at September 30, 2016 includes a $14 million reserve for uncertain tax positions from acquisitions that occurred during the third quarter.