Taxes	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
Taxes	Income Taxes Consistent with authoritative guidance, our estimated annual effective tax rate is used to allocate expected annual income tax expense to interim periods. The rate is the ratio of estimated annual income tax expense to estimated pre-tax ordinary income, and excludes "discrete items," which are significant, unusual or infrequent items reported separately net of their related tax effect. The estimated annual effective tax rate is applied to the current interim period's ordinary income to determine the income tax expense allocated to the interim period. The income tax effects of discrete items are then determined separately and recognized in the interim period in which the income or expense items arise. Our estimated annual effective tax rate for the second quarter of 2017 is approximately 33%, compared with approximately 37% for the same period in 2016. The decrease in the rate is due to an increase in the benefit from tax credits in the current year.

Taxes

6 Months Ended

Jun. 30, 2017

Income Taxes

Consistent with authoritative guidance, our estimated annual effective tax rate is used to allocate expected annual income tax expense to interim periods. The rate is the ratio of estimated annual income tax expense to estimated pre-tax ordinary income, and excludes "discrete items," which are significant, unusual or infrequent items reported separately net of their related tax effect. The estimated annual effective tax rate is applied to the current interim period's ordinary income to determine the income tax expense allocated to the interim period. The income tax effects of discrete items are then determined separately and recognized in the interim period in which the income or expense items arise.

Our estimated annual effective tax rate for the second quarter of 2017 is approximately 33%, compared with approximately 37% for the same period in 2016. The decrease in the rate is due to an increase in the benefit from tax credits in the current year.