REVENUE (Tables)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue [Table Text Block]

The following tables disaggregate WESCO’s revenue by end market and geography:



	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
Industrial	$	723,869	$	722,227	$	2,243,590	$	2,111,813
Construction	686,165		674,996		2,007,708		1,870,406
Utility	345,937		312,501		998,438		861,162
Commercial, Institutional and Government ("CIG")	311,274		290,435		915,418		838,994
Total by end market	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375



	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
United States	$	1,525,393	$	1,473,016	$	4,571,533	$	4,267,684
Other ⁽¹⁾	541,852		527,143		1,593,621		1,414,691
Total by geography	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375


⁽¹⁾	Other primarily includes net sales originating in Canada.

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 anticipated performance, historical data, as well as current and forecasted information. Measurement and recognition of variable consideration is reviewed by management on a monthly basis and revenue is adjusted accordingly. Variable consideration reduced revenue for the three months ended September 30, 2018 and 2017 by approximately $25.1 million and $24.2 million, respectively, and by approximately $74.5 million and $66.5 million for the nine months ended September 30, 2018 and 2017, respectively.