Income Taxes	9 Months Ended
Sep. 30, 2016
Income Taxes
Income Taxes	Note 6—Income Taxes Tax rate—Transocean Ltd., a holding company and Swiss resident, is exempt from cantonal and communal income tax in Switzerland, but is subject to Swiss federal income tax. Our provision for income taxes is based on the tax laws and rates applicable in the jurisdictions in which we operate and earn income. In the nine months ended September 30, 2016 and 2015, our estimated effective tax rate, excluding discrete items, was 21.5 percent and 18.0 percent, respectively, based on estimated annual income from continuing operations before income taxes. For the nine months ended September 30, 2016 and 2015, the effect of the various discrete period tax items was a net tax benefit of $34 million and $9 million, respectively. In the nine months ended September 30, 2016, such discrete items were primarily related to the tax expense or benefits of changes in unrecognized tax benefits associated with tax positions taken in prior years and valuation allowances on deferred tax assets for losses not expected to be realized. In the nine months ended September 30, 2015, such discrete items were primarily related to the tax effect of insurance recoveries that resulted from the resolution of certain matters associated with the Macondo well incident and losses on impairment of certain assets and changes in unrecognized tax benefits associated with tax positions taken in prior years. Tax returns—We file federal and local tax returns in several jurisdictions throughout the world. With few exceptions, we are no longer subject to examinations of our U.S. and non‑U.S. tax matters for years prior to 2010. Our tax returns in the major jurisdictions in which we operate, other than the U.S., Norway and Brazil, which are mentioned below, are generally subject to examination for periods ranging from three to six years. We have agreed to extensions beyond the statute of limitations in two major jurisdictions for up to 20 years. Tax authorities in certain jurisdictions are examining our tax returns and in some cases have issued assessments. We are defending our tax positions in those jurisdictions. While we cannot predict or provide assurance as to the timing or the outcome of these proceedings, we do not expect the ultimate liability to have a material adverse effect on our condensed consolidated statement of financial position or results of operations, although it may have a material adverse effect on our condensed consolidated statement of cash flows. U.S. tax investigations—In January 2014, we received a draft assessment from the U.S. tax authorities related to our 2010 and 2011 U.S. federal income tax returns. The significant issue raised in the assessment was related to transfer pricing for certain charters of drilling rigs between our subsidiaries. In April 2016, we entered into a final settlement with the U.S. tax authorities for $31 million, excluding interest and penalties, related to our 2010 and 2011 U.S. federal income tax returns. The terms of this settlement are not necessarily indicative of positions that the U.S. tax authorities may take on transfer pricing or other matters with respect to our tax returns for the years following 2012. Norway tax investigations and trial—Norwegian civil tax authorities are investigating certain transactions undertaken by our subsidiaries in 1999, 2001 and 2002 as well as the actions of certain employees of our former external tax advisors on these transactions. At September 30, 2016, the remaining outstanding civil tax assessment was for NOK 412 million, equivalent to approximately $52 million, plus interest, related to a 2001 dividend payment. On June 26, 2014, the Norwegian district court in Oslo ruled that our subsidiary was liable for the civil tax assessment but waived all penalties and interest. On September 12, 2014, we and the tax authorities each appealed the ruling. On June 27, 2016, the tax authorities withdrew their appeal of penalties and dropped all penalty claims. We intend to take all other appropriate action to continue to support our position that our Norwegian tax returns are materially correct as filed. Although we are unable to predict the outcome of this matter, we do not expect the effect, if any, to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows. Brazil tax investigations—Certain of our Brazilian income tax returns for the years 2000 through 2004 are currently under examination. In December 2005, the Brazilian tax authorities issued an aggregate tax assessment of BRL 806 million, equivalent to approximately $247 million, including penalties and interest, measured as of September 30, 2016. On January 25, 2008, we filed a protest letter with the Brazilian tax authorities, and we are currently engaged in the appeals process. On May 19, 2014, with respect to our Brazilian income tax returns for the years 2009 and 2010, the Brazilian tax authorities issued an aggregate tax assessment of BRL 137 million, equivalent to approximately $42 million, including penalties and interest, measured as of September 30, 2016. On June 18, 2014, we filed a protest letter with the Brazilian tax authorities. We believe our returns are materially correct as filed, and we are vigorously contesting these assessments. An unfavorable outcome on these proposed assessments could result in a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows. Other tax matters—We conduct operations through our various subsidiaries in a number of countries throughout the world. Each country has its own tax regimes with varying nominal rates, deductions, employee contribution requirements and tax attributes. From time to time, we may identify changes to previously evaluated tax positions that could result in adjustments to our recorded assets and liabilities. Although we are unable to predict the outcome of these changes, we do not expect the effect, if any, resulting from these adjustments to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Note 6—Income Taxes

Tax rate—Transocean Ltd., a holding company and Swiss resident, is exempt from cantonal and communal income tax in Switzerland, but is subject to Swiss federal income tax. Our provision for income taxes is based on the tax laws and rates applicable in the jurisdictions in which we operate and earn income. In the nine months ended September 30, 2016 and 2015, our estimated effective tax rate, excluding discrete items, was 21.5 percent and 18.0 percent, respectively, based on estimated annual income from continuing operations before income taxes. For the nine months ended September 30, 2016 and 2015, the effect of the various discrete period tax items was a net tax benefit of $34 million and $9 million, respectively. In the nine months ended September 30, 2016, such discrete items were primarily related to the tax expense or benefits of changes in unrecognized tax benefits associated with tax positions taken in prior years and valuation allowances on deferred tax assets for losses not expected to be realized. In the nine months ended September 30, 2015, such discrete items were primarily related to the tax effect of insurance recoveries that resulted from the resolution of certain matters associated with the Macondo well incident and losses on impairment of certain assets and changes in unrecognized tax benefits associated with tax positions taken in prior years.

Tax returns—We file federal and local tax returns in several jurisdictions throughout the world. With few exceptions, we are no longer subject to examinations of our U.S. and non‑U.S. tax matters for years prior to 2010. Our tax returns in the major jurisdictions in which we operate, other than the U.S., Norway and Brazil, which are mentioned below, are generally subject to examination for periods ranging from three to six years. We have agreed to extensions beyond the statute of limitations in two major jurisdictions for up to 20 years. Tax authorities in certain jurisdictions are examining our tax returns and in some cases have issued assessments. We are defending our tax positions in those jurisdictions. While we cannot predict or provide assurance as to the timing or the outcome of these proceedings, we do not expect the ultimate liability to have a material adverse effect on our condensed consolidated statement of financial position or results of operations, although it may have a material adverse effect on our condensed consolidated statement of cash flows.

U.S. tax investigations—In January 2014, we received a draft assessment from the U.S. tax authorities related to our 2010 and 2011 U.S. federal income tax returns. The significant issue raised in the assessment was related to transfer pricing for certain charters of drilling rigs between our subsidiaries. In April 2016, we entered into a final settlement with the U.S. tax authorities for $31 million, excluding interest and penalties, related to our 2010 and 2011 U.S. federal income tax returns. The terms of this settlement are not necessarily indicative of positions that the U.S. tax authorities may take on transfer pricing or other matters with respect to our tax returns for the years following 2012.

Norway tax investigations and trial—Norwegian civil tax authorities are investigating certain transactions undertaken by our subsidiaries in 1999, 2001 and 2002 as well as the actions of certain employees of our former external tax advisors on these transactions. At September 30, 2016, the remaining outstanding civil tax assessment was for NOK 412 million, equivalent to approximately $52 million, plus interest, related to a 2001 dividend payment. On June 26, 2014, the Norwegian district court in Oslo ruled that our subsidiary was liable for the civil tax assessment but waived all penalties and interest. On September 12, 2014, we and the tax authorities each appealed the ruling. On June 27, 2016, the tax authorities withdrew their appeal of penalties and dropped all penalty claims. We intend to take all other appropriate action to continue to support our position that our Norwegian tax returns are materially correct as filed. Although we are unable to predict the outcome of this matter, we do not expect the effect, if any, to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Brazil tax investigations—Certain of our Brazilian income tax returns for the years 2000 through 2004 are currently under examination. In December 2005, the Brazilian tax authorities issued an aggregate tax assessment of BRL 806 million, equivalent to approximately $247 million, including penalties and interest, measured as of September 30, 2016. On January 25, 2008, we filed a protest letter with the Brazilian tax authorities, and we are currently engaged in the appeals process. On May 19, 2014, with respect to our Brazilian income tax returns for the years 2009 and 2010, the Brazilian tax authorities issued an aggregate tax assessment of BRL 137 million, equivalent to approximately $42 million, including penalties and interest, measured as of September 30, 2016. On June 18, 2014, we filed a protest letter with the Brazilian tax authorities. We believe our returns are materially correct as filed, and we are vigorously contesting these assessments. An unfavorable outcome on these proposed assessments could result in a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Other tax matters—We conduct operations through our various subsidiaries in a number of countries throughout the world. Each country has its own tax regimes with varying nominal rates, deductions, employee contribution requirements and tax attributes. From time to time, we may identify changes to previously evaluated tax positions that could result in adjustments to our recorded assets and liabilities. Although we are unable to predict the outcome of these changes, we do not expect the effect, if any, resulting from these adjustments to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.