INCOME TAXES	6 Months Ended
Jun. 30, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	11. INCOME TAXES The effective tax rate for the three and six months ended June 30, 2018 was 21.5% and 20.7%, respectively. The effective tax rate for the three and six months ended June 30, 2017 was 25.3% and 25.1%, 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. 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 June 30, 2018. On August 1, 2018, the Internal Revenue Service issued proposed regulations regarding Section 965 of the Internal Revenue Code, as amended by the TCJA. We are currently reviewing the proposed regulations and future adjustments (if any) will be recognized as discrete income tax expense or benefit in the period the adjustments are determined.

11. INCOME TAXES

The effective tax rate for the three and six months ended June 30, 2018 was 21.5% and 20.7%, respectively. The effective tax rate for the three and six months ended June 30, 2017 was 25.3% and 25.1%, 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.

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 June 30, 2018. On August 1, 2018, the Internal Revenue Service issued proposed regulations regarding Section 965 of the Internal Revenue Code, as amended by the TCJA. We are currently reviewing the proposed regulations and future adjustments (if any) will be recognized as discrete income tax expense or benefit in the period the adjustments are determined.