Income Taxes	3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [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). Tax jurisdictions with a projected or year to date loss for which a tax benefit cannot be realized are excluded. The tax effects 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. We have open tax years from 2008 to 2017 with various significant tax jurisdictions. In the three months ended March 31, 2018 Income tax expense of $466 million primarily resulted from tax expense attributable to entities included in our effective tax rate calculation. The recorded effective tax rate is higher than the applicable statutory tax rate due primarily to losses incurred in jurisdictions for which a valuation allowance is recorded. In the three months ended March 31, 2017 Income tax expense of $787 million primarily resulted from tax expense attributable to entities included in our effective tax rate calculation of $898 million including tax benefits from foreign dividends, partially offset by tax benefits related to tax settlements. At March 31, 2018 we had $22.8 billion of net deferred tax assets consisting of net operating losses and income tax credits, capitalized research expenditures and other timing differences that are available to offset future income tax liabilities, partially offset by valuation allowances. The Tax Act was signed into law on December 22, 2017. The Tax Act changed many aspects of U.S. corporate income taxation and included reduction of the corporate income tax rate from 35% to 21%, implementation of a territorial tax system and imposition of a tax on deemed repatriated earnings of foreign subsidiaries. We recognized the tax effects of the Tax Act in the three months ended December 31, 2017 and recorded $7.3 billion in tax expense. The tax expense relates almost entirely to the remeasurement of deferred tax assets to the 21% tax rate. Upon completion of our 2017 U.S. income tax return later in 2018 we may identify additional remeasurement adjustments to our recorded deferred tax assets. We will continue to assess our provision for income taxes as future guidance is issued but do not currently anticipate significant revisions will be necessary. Any such revisions will be treated in accordance with the measurement period guidance outlined in Staff Accounting Bulletin No. 118.

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). Tax jurisdictions with a projected or year to date loss for which a tax benefit cannot be realized are excluded. The tax effects 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. We have open tax years from 2008 to 2017 with various significant tax jurisdictions.

In the three months ended March 31, 2018 Income tax expense of $466 million primarily resulted from tax expense attributable to entities included in our effective tax rate calculation. The recorded effective tax rate is higher than the applicable statutory tax rate due primarily to losses incurred in jurisdictions for which a valuation allowance is recorded. In the three months ended March 31, 2017 Income tax expense of $787 million primarily resulted from tax expense attributable to entities included in our effective tax rate calculation of $898 million including tax benefits from foreign dividends, partially offset by tax benefits related to tax settlements.

At March 31, 2018 we had $22.8 billion of net deferred tax assets consisting of net operating losses and income tax credits, capitalized research expenditures and other timing differences that are available to offset future income tax liabilities, partially offset by valuation allowances.

The Tax Act was signed into law on December 22, 2017. The Tax Act changed many aspects of U.S. corporate income taxation and included reduction of the corporate income tax rate from 35% to 21%, implementation of a territorial tax system and imposition of a tax on deemed repatriated earnings of foreign subsidiaries. We recognized the tax effects of the Tax Act in the three months ended December 31, 2017 and recorded $7.3 billion in tax expense. The tax expense relates almost entirely to the remeasurement of deferred tax assets to the 21% tax rate. Upon completion of our 2017 U.S. income tax return later in 2018 we may identify additional remeasurement adjustments to our recorded deferred tax assets. We will continue to assess our provision for income taxes as future guidance is issued but do not currently anticipate significant revisions will be necessary. Any such revisions will be treated in accordance with the measurement period guidance outlined in Staff Accounting Bulletin No. 118.