Income Taxes	3 Months Ended
Apr. 29, 2018
Notes to financial statements [Abstract]
Income Taxes	Income Taxes We recognized income tax expense of $67 million and $29 million for the first quarter of fiscal years 2019 and 2018, respectively. Income tax expense as a percentage of income before income tax was 5.1% and 5.5% for the first quarter of fiscal years 2019 and 2018, respectively. The decrease in our effective tax rate in the first quarter of fiscal year 2019 as compared to the same period in the prior fiscal year is primarily due to a decrease in the U.S. statutory tax rate from 35% to 21%, partially offset by a decrease in the impact of tax benefits from stock-based compensation. Our effective tax rates for the first quarter of fiscal years 2019 and 2018 of 5.1% and 5.5%, respectively, were lower than the U.S. federal statutory rates of 21% and 33.9%, for fiscal years 2019 and 2018, respectively, due primarily to income earned in jurisdictions where the tax rate is lower than the U.S. federal statutory tax rate, tax benefits related to stock-based compensation, and the benefit of the U.S. federal research tax credit. In December 2017, the SEC issued guidance that allows companies to record provisional amounts for the tax effects of the Tax Cuts and Job Acts, or TCJA, during a measurement period not to exceed one year. The TCJA was effective in the fourth quarter of fiscal year 2018 and we have recorded provisional amounts based on reasonable estimates for those tax effects. For the first quarter of fiscal year 2019, we have not recorded any adjustments to our provisional amounts. We will continue our analysis of these provisional amounts, which are still subject to change during the measurement period, and we anticipate further guidance on accounting interpretations from the FASB and application of the law from the U.S. Department of Treasury. The TCJA subjects a U.S. corporation to tax on its global intangible low-taxed income, or GILTI. Under U.S. GAAP, we can make an accounting policy election to either treat taxes due on the GILTI as a current period expense or factor such amounts into our measurement of deferred taxes. Given the complexity of the GILTI provisions, we are still evaluating its effects and have not yet determined our accounting policy. We expect to complete our analysis within the measurement period. For the first quarter of fiscal year 2019, because we are still evaluating the effects of the GILTI provisions, we have included tax expense related to GILTI for current-year operations in our estimated annual effective tax rate and have not provided for GILTI on deferred items. For the first quarter of fiscal year 2019, there have been no material changes to our tax years that remain subject to examination by major tax jurisdictions. Additionally, there have been no material changes to our unrecognized tax benefits and any related interest or penalties since the fiscal year ended January 28, 2018. While we believe that we have adequately provided for all uncertain tax positions, or tax positions where we believe it is not more-likely-than-not that the position will be sustained upon review, amounts asserted by tax authorities could be greater or less than our accrued position. Accordingly, our provisions on federal, state and foreign tax related matters to be recorded in the future may change as revised estimates are made or the underlying matters are settled or otherwise resolved with the respective tax authorities. As of April 29, 2018, we do not believe that our estimates, as otherwise provided for, on such tax positions will significantly increase or decrease within the next twelve months.

Income Taxes

We recognized income tax expense of $67 million and $29 million for the first quarter of fiscal years 2019 and 2018, respectively. Income tax expense as a percentage of income before income tax was 5.1% and 5.5% for the first quarter of fiscal years 2019 and 2018, respectively.

The decrease in our effective tax rate in the first quarter of fiscal year 2019 as compared to the same period in the prior fiscal year is primarily due to a decrease in the U.S. statutory tax rate from 35% to 21%, partially offset by a decrease in the impact of tax benefits from stock-based compensation.

Our effective tax rates for the first quarter of fiscal years 2019 and 2018 of 5.1% and 5.5%, respectively, were lower than the U.S. federal statutory rates of 21% and 33.9%, for fiscal years 2019 and 2018, respectively, due primarily to income earned in jurisdictions where the tax rate is lower than the U.S. federal statutory tax rate, tax benefits related to stock-based compensation, and the benefit of the U.S. federal research tax credit.

In December 2017, the SEC issued guidance that allows companies to record provisional amounts for the tax effects of the Tax Cuts and Job Acts, or TCJA, during a measurement period not to exceed one year. The TCJA was effective in the fourth quarter of fiscal year 2018 and we have recorded provisional amounts based on reasonable estimates for those tax effects. For the first quarter of fiscal year 2019, we have not recorded any adjustments to our provisional amounts. We will continue our analysis of these provisional amounts, which are still subject to change during the measurement period, and we anticipate further guidance on accounting interpretations from the FASB and application of the law from the U.S. Department of Treasury.

The TCJA subjects a U.S. corporation to tax on its global intangible low-taxed income, or GILTI. Under U.S. GAAP, we can make an accounting policy election to either treat taxes due on the GILTI as a current period expense or factor such amounts into our measurement of deferred taxes. Given the complexity of the GILTI provisions, we are still evaluating its effects and have not yet determined our accounting policy. We expect to complete our analysis within the measurement period. For the first quarter of fiscal year 2019, because we are still evaluating the effects of the GILTI provisions, we have included tax expense related to GILTI for current-year operations in our estimated annual effective tax rate and have not provided for GILTI on deferred items.

For the first quarter of fiscal year 2019, there have been no material changes to our tax years that remain subject to examination by major tax jurisdictions. Additionally, there have been no material changes to our unrecognized tax benefits and any related interest or penalties since the fiscal year ended January 28, 2018.

While we believe that we have adequately provided for all uncertain tax positions, or tax positions where we believe it is not more-likely-than-not that the position will be sustained upon review, amounts asserted by tax authorities could be greater or less than our accrued position. Accordingly, our provisions on federal, state and foreign tax related matters to be recorded in the future may change as revised estimates are made or the underlying matters are settled or otherwise resolved with the respective tax authorities. As of April 29, 2018, we do not believe that our estimates, as otherwise provided for, on such tax positions will significantly increase or decrease within the next twelve months.