OTHER FINANCIAL INFORMATION (Tables)

12 Months Ended

Dec. 31, 2018

Condensed Financial Information [Abstract]

Condensed Balance Sheet [Table Text Block]



	Condensed Consolidating Balance Sheet
	December 31, 2018
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	35,931	$	60,412		$	—		$	96,343
Trade accounts receivable, net	—		—		1,166,607			—			1,166,607
Inventories	—		440,422		508,304			—			948,726
Prepaid expenses and other current assets	1,123		57,586		124,523			(9,268		)	173,964
Total current assets	1,123		533,939		1,859,846			(9,268		)	2,385,640
Intercompany receivables, net	—		—		2,403,704			(2,403,704		)	—
Property, buildings and equipment, net	—		63,506		97,372			—			160,878
Intangible assets, net	—		2,131		313,885			—			316,016
Goodwill	—		257,623		1,464,980			—			1,722,603
Investments in affiliates	3,182,469		5,137,783					(8,320,252		)	—
Other assets	—		2,905		16,994						19,899
Total assets	$	3,183,592	$	5,997,887	$	6,156,781		$	(10,733,224	)	$	4,605,036

Accounts payable	$	—	$	404,373	$	389,975		$	—		$	794,348
Short-term debt	—		—		30,785			—			30,785
Other current liabilities	—		86,600		159,481			(9,268		)	236,813
Total current liabilities	—		490,973		580,241			(9,268		)	1,061,946
Intercompany payables, net	1,048,282		1,355,422		—			(2,403,704		)	—
Long-term debt	—		842,093		325,218			—			1,167,311
Other noncurrent liabilities	—		126,930		119,123			—			246,053
Total WESCO International stockholders’ equity	2,135,310		3,182,469		5,137,783			(8,320,252		)	2,135,310
Noncontrolling interests	—		—		(5,584		)	—			(5,584		)
Total liabilities and stockholders’ equity	$	3,183,592	$	5,997,887	$	6,156,781		$	(10,733,224	)	$	4,605,036



	Condensed Consolidating Balance Sheet
	December 31, 2017
	(In thousands)
	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	50,602	$	67,351		$	—		$	117,953
Trade accounts receivable, net	—		—		1,170,080			—			1,170,080
Inventories	—		430,092		526,056			—			956,148
Prepaid expenses and other current assets	4,730		42,547		152,531			(35,140		)	164,668
Total current assets	4,730		523,241		1,916,018			(35,140		)	2,408,849
Intercompany receivables, net	—		—		2,189,136			(2,189,136		)	—
Property, buildings and equipment, net	—		50,198		106,247			—			156,445
Intangible assets, net	—		2,770		364,334			—			367,104
Goodwill	—		257,623		1,514,254			—			1,771,877
Investments in affiliates	3,058,613		5,023,826		—			(8,082,439		)	—
Other assets	—		2,778		28,415			—			31,193
Total assets	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468

Accounts payable	$	—	$	417,690	$	381,830		$	—		$	799,520
Short-term debt	—		—		34,075			—			34,075
Other current liabilities	—		80,039		162,475			(35,140		)	207,374
Total current liabilities	—		497,729		578,380			(35,140		)	1,040,969
Intercompany payables, net	939,784		1,249,352		—			(2,189,136		)	—
Long-term debt	—		934,033		379,228			—			1,313,261
Other noncurrent liabilities	3,820		120,709		140,566			—			265,095
Total WESCO International stockholders’ equity	2,119,739		3,058,613		5,023,826			(8,082,439		)	2,119,739
Noncontrolling interests	—		—		(3,596		)	—			(3,596		)
Total liabilities and stockholders’ equity	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468

Condensed Income Statement [Table Text Block]



	Condensed Consolidating Statement of Income and Comprehensive Income
	Year ended December 31, 2018
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	3,572,406		$	4,757,321		$	(153,126	)	$	8,176,601
Cost of goods sold (excluding depreciation and	—			2,890,490			3,871,856			(153,126		)	6,609,220
amortization)
Selling, general and administrative expenses	—			590,009			561,935			—			1,151,944
Depreciation and amortization	—			18,334			44,663			—			62,997
Results of affiliates’ operations	225,355			209,802			—			(435,157		)	—
Net interest and other	—			54,178			17,237			—			71,415
Provision for income taxes	—			3,842			51,828			—			55,670
Net income	225,355			225,355			209,802			(435,157		)	225,355
Less: Net loss attributable to noncontrolling interests	—			—			(1,988		)	—			(1,988		)
Net income attributable to WESCO International	$	225,355		$	225,355		$	211,790		$	(435,157	)	$	227,343
Other comprehensive income (loss):
Foreign currency translation adjustments	(99,643		)	(99,643		)	(99,643		)	199,286			(99,643		)
Post retirement benefit plan adjustments, net of tax	3,798			3,798			3,798			(7,596		)	3,798
Comprehensive income attributable to WESCO International	$	129,510		$	129,510		$	115,945		$	(243,467	)	$	131,498



	Condensed Consolidating Statement of Income and Comprehensive Income
	Year ended December 31, 2017
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	3,370,088		$	4,441,655		$	(132,722	)	$	7,679,021
Cost of goods sold (excluding depreciation and	—			2,714,511			3,612,577			(132,722		)	6,194,366
amortization)
Selling, general and administrative expenses	—			555,503			546,095			—			1,101,598
Depreciation and amortization	—			18,442			45,575			—			64,017
Results of affiliates’ operations	160,587			168,782			—			(329,369		)	—
Net interest and other	—			94,313			(27,713		)	—			66,600
Provision for income taxes	(2,546		)	(4,486		)	96,339			—			89,307
Net income	163,133			160,587			168,782			(329,369		)	163,133
Less: Net loss attributable to noncontrolling interests	—			—			(327		)	—			(327		)
Net income attributable to WESCO International	$	163,133		$	160,587		$	169,109		$	(329,369	)	$	163,460
Other comprehensive income (loss):
Foreign currency translation adjustments	85,762			85,762			85,762			(171,524		)	85,762
Post retirement benefit plan adjustments, net of tax	(6,381		)	(6,381		)	(6,381		)	12,762			(6,381		)
Comprehensive income attributable to WESCO International	$	242,514		$	239,968		$	248,490		$	(488,131	)	$	242,841



	Condensed Consolidating Statement of Income and Comprehensive Income
	Year ended December 31, 2016
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	3,306,265		$	4,134,508		$	(104,756	)	$	7,336,017
Cost of goods sold (excluding depreciation and	—			2,651,409			3,341,161			(104,756		)	5,887,814
amortization)
Selling, general and administrative expenses	61			477,437			573,301			—			1,050,799
Depreciation and amortization	—			20,226			46,632			—			66,858
Results of affiliates’ operations	240,571			155,814			—			(396,385		)	—
Net interest and other	17,555			87,824			(30,317		)	—			75,062
Loss on debt redemption	123,933			—			—			—			123,933
Provision for income taxes	(2,098		)	8,263			24,266			—			30,431
Net income	$	101,120		$	216,920		$	179,465		$	(396,385	)	$	101,120
Less: Net loss attributable to noncontrolling interests	—			—			(468		)	—			(468		)
Net income attributable to WESCO International	$	101,120		$	216,920		$	179,933		$	(396,385	)	$	101,588
Other comprehensive income (loss):
Foreign currency translation adjustments	38,275			38,275			38,275			(76,550		)	38,275
Post retirement benefit plan adjustments, net of tax	(2,485		)	(2,485		)	(2,485		)	4,970			(2,485		)
Comprehensive income attributable to WESCO International	$	136,910		$	252,710		$	215,723		$	(467,965	)	$	137,378

Condensed Cash Flow Statement [Table Text Block]



	Condensed Consolidating Statement of Cash Flows
	Year ended December 31, 2017
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash (used in) provided by operating activities	$	(36,575	)	$	101,826		$	83,871		$	—		$	149,122
Investing activities:
Capital expenditures	—			(13,215		)	(8,292		)	—			(21,507		)
Proceeds from sale of assets	—			—			6,766			—			6,766
Dividends received from subsidiaries	—			307,784			—			(307,784		)	—
Advances to subsidiaries and other	—			(383,686		)	26,912			366,220			9,446
Net cash (used in) provided by investing activities	—			(89,117		)	25,386			58,436			(5,295		)
Financing activities:
Proceeds from issuance of debt	143,367			775,926			1,144,848			(383,686		)	1,680,455
Repayments of debt	—			(785,392		)	(952,740		)	17,466			(1,720,666		)
Equity activities	(106,792		)	—			—			—			(106,792		)
Dividends paid by subsidiaries	—			—			(307,784		)	307,784			—
Other	—			5,807			—			—			5,807
Net cash provided by (used in) financing activities	36,575			(3,659		)	(115,676		)	(58,436		)	(141,196		)
Effect of exchange rate changes on cash and cash equivalents	—			—			5,191			—			5,191
Net change in cash and cash equivalents	—			9,050			(1,228		)	—			7,822
Cash and cash equivalents at the beginning of period	—			41,552			68,579			—			110,131
Cash and cash equivalents at the end of period	$	—		$	50,602		$	67,351		$	—		$	117,953



	Condensed Consolidating Statement of Cash Flows
	Year ended December 31, 2018
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash provided by operating activities	$	18,672		$	153,467		$	124,582		$	—		$	296,721
Investing activities:
Capital expenditures	—			(17,573		)	(18,637		)	—			(36,210		)
Proceeds from sale of assets	—			—			12,461			—			12,461
Dividends received from subsidiaries				347,531						(347,531		)	—
Advances to subsidiaries and other	—			(406,028		)	196,219			199,416			(10,393		)
Net cash (used in) provided by investing activities	—			(76,070		)	190,043			(148,115		)	(34,142		)
Financing activities:
Proceeds from issuance of debt	108,497			339,606			1,086,673			(199,416		)	1,335,360
Repayments of debt	—			(410,606		)	(1,051,611		)	—			(1,462,217		)
Equity activities	(127,169		)	—			—			—			(127,169		)
Dividends paid by subsidiaries							(347,531		)	347,531			—
Other	—			(21,068		)	—			—			(21,068		)
Net cash used in financing activities	(18,672		)	(92,068		)	(312,469		)	148,115			(275,094		)
Effect of exchange rate changes on cash and cash equivalents							(9,095		)	—			(9,095		)
Net change in cash and cash equivalents	—			(14,671		)	(6,939		)	—			(21,610		)
Cash and cash equivalents at the beginning of period	—			50,602			67,351			—			117,953
Cash and cash equivalents at the end of period	$	—		$	35,931		$	60,412		$	—		$	96,343



	Condensed Consolidating Statement of Cash Flows
	Year ended December 31, 2016
	(In thousands)
	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash provided by (used in) operating activities	$	95,388		$	(243,476	)	$	448,323		$	—		$	300,235
Investing activities:
Capital expenditures	—			(12,482		)	(5,475		)	—			(17,957		)
Acquisition payments, net of cash acquired	—			(50,890		)	—			—			(50,890		)
Proceeds from sale of assets	—			—			8,361			—			8,361
Dividends received from subsidiaries	—			82,912			—			(82,912		)	—
Advances to subsidiaries and other	—			(297,259		)	(337,344		)	624,603			(10,000		)
Net cash used in investing activities	—			(277,719		)	(334,458		)	541,691			(70,486		)
Financing activities:
Proceeds from issuance of debt	252,246			1,566,864			672,345			(297,259		)	2,194,196
Repayments of debt	(344,804		)	(1,030,520		)	(752,401		)	(327,344		)	(2,455,069		)
Equity activities	(2,830		)	—			—			—			(2,830		)
Dividends paid by subsidiaries	—			—			(82,912		)	82,912			—
Other	—			(12,560		)	—			—			(12,560		)
Net cash (used in) provided by financing activities	(95,388		)	523,784			(162,968		)	(541,691		)	(276,263		)
Effect of exchange rate changes on cash and cash equivalents	—			—			(3,634		)	—			(3,634		)
Net change in cash and cash equivalents	—			2,589			(52,737		)	—			(50,148		)
Cash and cash equivalents at the beginning of period	—			38,963			121,316			—			160,279
Cash and cash equivalents at the end of period	$	—		$	41,552		$	68,579		$	—		$	110,131