INCOME TAXES	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	11. INCOME TAXES The effective tax rate for the three and nine months ended September 30, 2018 was 17.2% and 19.3%, respectively. The effective tax rate for the three and nine months ended September 30, 2017 was 25.5% and 25.3%, respectively. WESCO’s effective tax rate is typically impacted by the tax effect of intercompany financing, foreign tax rate differences, other nondeductible expenses and state income taxes. The effective tax rates for the current year periods are lower than the prior year periods primarily due to the Tax Cuts and Jobs Act of 2017 (the "TCJA"), which permanently reduced the U.S. federal statutory income tax rate from 35% to 21%, effective January 1, 2018. Also, the discrete benefits resulting from audit settlements favorably impacted the effective tax rate for the three months ended September 30, 2018. The unaudited condensed consolidated financial information presented herein reflects provisional amounts for certain income tax effects of the TCJA for which the accounting is incomplete, but a reasonable estimate can be determined, based on enacted tax laws and rates as of September 30, 2018. Since the enactment of the TCJA on December 22, 2017, the Internal Revenue Service has issued proposed regulations and guidance regarding Section 965 of the Internal Revenue Code, as amended by the TCJA. We have reviewed the proposed regulations and guidance, and they do not materially impact the provisional amounts previously recorded for the one-time tax on the deemed repatriation of undistributed foreign earnings. Future adjustments (if any) resulting from additional regulatory guidance will be recognized as discrete income tax expense or benefit in the period the adjustments are determined. The total amount of unrecognized tax benefits was reduced from $4.3 million to $1.6 million during the nine months ended September 30, 2018 due to audit settlements. The $1.6 million could affect the effective tax rate if recognized in the consolidated financial statements. It is reasonably possible that this amount will decrease by approximately $0.2 million within the next twelve months due to the expiration of statutes of limitation and the settlement of state audits.

11. INCOME TAXES

The effective tax rate for the three and nine months ended September 30, 2018 was 17.2% and 19.3%, respectively. The effective tax rate for the three and nine months ended September 30, 2017 was 25.5% and 25.3%, respectively. WESCO’s effective tax rate is typically impacted by the tax effect of intercompany financing, foreign tax rate differences, other nondeductible expenses and state income taxes. The effective tax rates for the current year periods are lower than the prior year periods primarily due to the Tax Cuts and Jobs Act of 2017 (the "TCJA"), which permanently reduced the U.S. federal statutory income tax rate from 35% to 21%, effective January 1, 2018. Also, the discrete benefits resulting from audit settlements favorably impacted the effective tax rate for the three months ended September 30, 2018.

The unaudited condensed consolidated financial information presented herein reflects provisional amounts for certain income tax effects of the TCJA for which the accounting is incomplete, but a reasonable estimate can be determined, based on enacted tax laws and rates as of September 30, 2018. Since the enactment of the TCJA on December 22, 2017, the Internal Revenue Service has issued proposed regulations and guidance regarding Section 965 of the Internal Revenue Code, as amended by the TCJA. We have reviewed the proposed regulations and guidance, and they do not materially impact the provisional amounts previously recorded for the one-time tax on the deemed repatriation of undistributed foreign earnings. Future adjustments (if any) resulting from additional regulatory guidance will be recognized as discrete income tax expense or benefit in the period the adjustments are determined.

The total amount of unrecognized tax benefits was reduced from $4.3 million to $1.6 million during the nine months ended September 30, 2018 due to audit settlements. The $1.6 million could affect the effective tax rate if recognized in the consolidated financial statements. It is reasonably possible that this amount will decrease by approximately $0.2 million within the next twelve months due to the expiration of statutes of limitation and the settlement of state audits.