|6 Months Ended|
Jun. 30, 2017
|Income Tax Disclosure [Abstract]|
Our effective tax rate decreased to 34.7% in the second quarter of 2017 from 35.0% in the same period of 2016 (33.4% year-to-date in 2017 compared to 35.1% in the same period of 2016). In the first quarter of 2017, we adopted a new accounting standard that requires the recognition of excess tax benefits related to share-based compensation in income tax expense (see note 2), which resulted in discrete tax benefits for the three months ended June 30, 2017 of $7 million ($62 million year-to-date) and reduced our second quarter effective tax rate by 0.3% (1.6% year-to-date).
As discussed in our Annual Report on Form 10-K for the year ended December 31, 2016, we have recognized liabilities for uncertain tax positions. We reevaluate these uncertain tax positions on a quarterly basis. A number of years may elapse before an uncertain tax position is audited and ultimately settled. It is difficult to predict the ultimate outcome or the timing of resolution for uncertain tax positions. It is reasonably possible that the amount of unrecognized tax benefits could significantly increase or decrease within the next twelve months. However, an estimate of the range of reasonably possible outcomes cannot be made. Items that may cause changes to unrecognized tax benefits include the timing of interest deductions and the allocation of income and expense between tax jurisdictions. These changes could result from the settlement of ongoing litigation, the completion of ongoing examinations, the expiration of the statute of limitations or other unforeseen circumstances.
The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.
Reference 1: http://www.xbrl.org/2003/role/presentationRef