REVENUE Revenue Reductions (Policies)

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Revenue Recognition, Revenue Reductions [Policy Text Block]

WESCO’s revenues are adjusted for variable consideration, which includes customer volume rebates, returns, and discounts. WESCO measures variable consideration by estimating expected outcomes using analysis and inputs based upon historical data, as well as current and forecasted information. Variable consideration is reviewed by management on a monthly basis and revenue is adjusted accordingly. Variable consideration reduced revenue for the years ended December 31, 2019, 2018 and 2017 by approximately $106.6 million, $107.4 million and $91.1 million, respectively.