Income Taxes	3 Months Ended
Mar. 31, 2012
Income Tax Expense (Benefit) [Abstract]
Income Taxes	Income Taxes For interim income tax reporting we estimate our annual effective tax rate and apply it to our year to date ordinary income/loss. The tax effect of unusual or infrequently occurring items, including changes in judgment about valuation allowances and effects of changes in tax laws or rates, are reported in the interim period in which they occur. Tax jurisdictions with a projected or year to date loss for which a tax benefit cannot be realized are excluded. In interim periods, income tax expense is comprised of two key elements: (1) the amount necessary to appropriately state the year to date estimated tax expense of entities included in our effective tax rate calculation, which is calculated as the difference between the amount currently estimated for the year to date period and the amount previously recorded in prior interim periods; and (2) the tax effect of unusual or infrequent items that occur in the period. In the three months ended March 31, 2012 and 2011 income tax expense of $216 million and $137 million primarily resulted from tax expense attributable to entities included in our effective tax rate calculation. The recorded effective tax rate is lower than the applicable statutory tax rate due primarily to income earned in jurisdictions for which a full valuation allowance is recorded. We file income tax returns in multiple jurisdictions and are subject to examination by taxing authorities throughout the world. We have open tax years from 2002 to 2011 with various significant tax jurisdictions. These open years contain matters that could be subject to differing interpretations of applicable tax laws and regulations as they relate to the amount, character, timing or inclusion of revenue and expenses or the sustainability of income tax credits for a given audit cycle. In addition the global nature of our operations means that transfer pricing disputes may arise. In March 2012 a Mexican income tax audit covering the 2004 tax year was concluded and an assessment of $134 million including tax, interest and penalties was issued. The total 2002, 2003 and 2004 assessments as of March 31, 2012 including tax, interest and penalties is $307 million. We believe we have adequate reserves established. Collection of any assessment will be suspended until a revised assessment is issued and during any subsequent proceedings through U.S. and Mexican competent authorities. At March 31, 2012 it is not possible to reasonably estimate the expected change to the total amount of unrecognized tax benefits in the next 12 months.

Income Taxes

3 Months Ended

Mar. 31, 2012

Income Tax Expense (Benefit) [Abstract]

For interim income tax reporting we estimate our annual effective tax rate and apply it to our year to date ordinary income/loss. The tax effect of unusual or infrequently occurring items, including changes in judgment about valuation allowances and effects of changes in tax laws or rates, are reported in the interim period in which they occur. Tax jurisdictions with a projected or year to date loss for which a tax benefit cannot be realized are excluded.

In interim periods, income tax expense is comprised of two key elements: (1) the amount necessary to appropriately state the year to date estimated tax expense of entities included in our effective tax rate calculation, which is calculated as the difference between the amount currently estimated for the year to date period and the amount previously recorded in prior interim periods; and (2) the tax effect of unusual or infrequent items that occur in the period.

In the three months ended March 31, 2012 and 2011 income tax expense of $216 million and $137 million primarily resulted from tax expense attributable to entities included in our effective tax rate calculation. The recorded effective tax rate is lower than the applicable statutory tax rate due primarily to income earned in jurisdictions for which a full valuation allowance is recorded.

We file income tax returns in multiple jurisdictions and are subject to examination by taxing authorities throughout the world. We have open tax years from 2002 to 2011 with various significant tax jurisdictions. These open years contain matters that could be subject to differing interpretations of applicable tax laws and regulations as they relate to the amount, character, timing or inclusion of revenue and expenses or the sustainability of income tax credits for a given audit cycle. In addition the global nature of our operations means that transfer pricing disputes may arise.

In March 2012 a Mexican income tax audit covering the 2004 tax year was concluded and an assessment of $134 million including tax, interest and penalties was issued. The total 2002, 2003 and 2004 assessments as of March 31, 2012 including tax, interest and penalties is $307 million. We believe we have adequate reserves established. Collection of any assessment will be suspended until a revised assessment is issued and during any subsequent proceedings through U.S. and Mexican competent authorities.

At March 31, 2012 it is not possible to reasonably estimate the expected change to the total amount of unrecognized tax benefits in the next 12 months.