Income Taxes	6 Months Ended
Jul. 31, 2016
Notes to financial statements [Abstract]
Income Taxes	Income Taxes We recognized income tax expense of $64 million and $109 million for the three and six months ended July 31, 2016, respectively, and $46 million and $84 million for the three and six months ended July 26, 2015, respectively. Our effective tax rate was 20.3% and 19.6% for the three and six months ended July 31, 2016, respectively, and 64.0% and 34.3% for the three and six months ended July 26, 2015, respectively. The decrease in our effective tax rate in the three and six months ended July 31, 2016 compared to the same periods in the prior fiscal year was primarily due to the absence of tax-related restructuring charges recorded in the three months ended July 26, 2015, the favorable benefit of the U.S. federal research tax credit, which was permanently re-enacted in December 2015, and lower permanent tax differences related to stock-based compensation, partly offset by an increase in the amount of earnings subject to U.S. tax. Our effective tax rate for the six months ended July 31, 2016 of 19.6% was lower than the U.S. federal statutory rate of 35% due primarily to income earned in jurisdictions where the tax rate is lower than the U.S. federal statutory tax rate, the benefit of the U.S. federal research tax credit and discrete events that occurred during the six months ended July 31, 2016 primarily attributable to tax benefits recognized upon the expiration of statutes of limitations in certain non-U.S. jurisdictions. During the three months ended July 31, 2016, we reduced certain unrecognized tax benefits related to various U.S. state income tax positions by $48 million as the state of California settled its review of our fiscal years 2011 and 2012. As a result, we recognized a $13 million state tax benefit, net of the agreed settlement, in the form of a deferred tax asset that is subject to a full valuation allowance. For the six months ended July 31, 2016, there have been no other significant changes to our tax years that remain subject to review by major tax jurisdictions. Further, there have been no other significant changes to our unrecognized tax benefits and any related interest or penalties since the fiscal year ended January 31, 2016, other than the closure of our aforementioned state income tax position and the recognition of tax benefits upon the expiration of statutes of limitations in certain non-U.S. jurisdictions in the six months ended July 31, 2016. 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 July 31, 2016, 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 $64 million and $109 million for the three and six months ended July 31, 2016, respectively, and $46 million and $84 million for the three and six months ended July 26, 2015, respectively. Our effective tax rate was 20.3% and 19.6% for the three and six months ended July 31, 2016, respectively, and 64.0% and 34.3% for the three and six months ended July 26, 2015, respectively.

The decrease in our effective tax rate in the three and six months ended July 31, 2016 compared to the same periods in the prior fiscal year was primarily due to the absence of tax-related restructuring charges recorded in the three months ended July 26, 2015, the favorable benefit of the U.S. federal research tax credit, which was permanently re-enacted in December 2015, and lower permanent tax differences related to stock-based compensation, partly offset by an increase in the amount of earnings subject to U.S. tax.

Our effective tax rate for the six months ended July 31, 2016 of 19.6% was lower than the U.S. federal statutory rate of 35% due primarily to income earned in jurisdictions where the tax rate is lower than the U.S. federal statutory tax rate, the benefit of the U.S. federal research tax credit and discrete events that occurred during the six months ended July 31, 2016 primarily attributable to tax benefits recognized upon the expiration of statutes of limitations in certain non-U.S. jurisdictions.

During the three months ended July 31, 2016, we reduced certain unrecognized tax benefits related to various U.S. state income tax positions by $48 million as the state of California settled its review of our fiscal years 2011 and 2012. As a result, we recognized a $13 million state tax benefit, net of the agreed settlement, in the form of a deferred tax asset that is subject to a full valuation allowance. For the six months ended July 31, 2016, there have been no other significant changes to our tax years that remain subject to review by major tax jurisdictions. Further, there have been no other significant changes to our unrecognized tax benefits and any related interest or penalties since the fiscal year ended January 31, 2016, other than the closure of our aforementioned state income tax position and the recognition of tax benefits upon the expiration of statutes of limitations in certain non-U.S. jurisdictions in the six months ended July 31, 2016.

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 July 31, 2016, 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.