|9 Months Ended|
Sep. 30, 2018
|Income Tax Disclosure [Abstract]|
On December 22, 2017, President Trump signed into law H.R. 1, “An Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018” (this legislation was formerly called the “Tax Cuts and Jobs Act” and is referred to herein as the “U.S. Tax Act”). The U.S. Tax Act provides for significant changes in the U.S. Internal Revenue Code of 1986, as amended. The U.S. Tax Act contains provisions with separate effective dates but is generally effective for taxable years beginning after December 31, 2017. Beginning on January 1, 2018, the U.S. Tax Act lowers the U.S. corporate income tax rate from 35% to 21% on our U.S. earnings from that date and beyond.
The ultimate impact of the U.S. Tax Act on our reported results in 2018 may differ from the estimates provided herein, possibly materially, due to, among other things, changes in interpretations and assumptions we have made, guidance that may be issued, and other actions we may take as a result of the U.S. Tax Act different from that presently contemplated. On December 22, 2017, the SEC staff issued SAB 118 that allows us to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. We currently are analyzing the U.S. Tax Act, and in certain areas, have made reasonable estimates of the effects on our consolidated financial statements and tax disclosures, including the changes to our existing deferred tax balances.
For the three months ended September 30, 2018 and 2017, the effective income tax rates varied from the statutory federal income tax rate of 21.0% and 35.0%, primarily as a result of the effect of state income taxes, net of the federal benefit, and permanent differences between book and tax net income. The combined federal and state effective tax rate for the nine months ended September 30, 2018 was 24.9% compared to a rate of 34.4% for the same period in 2017. The lower effective tax rate for the nine months ended September 30, 2018 is the result of the enactment of the U.S. Tax Act, which lowered the statutory federal income tax rate to 21.0% from 35.0%. The lower rate was partly offset by fuel tax benefits taken in the nine months ended September 30, 2018 that were not deductible for tax purposes and 2017 benefiting from qualified production property deductions.
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