The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(b))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

EMPLOYEE BENEFIT PLANS TEXTUALS (Details) $ in Thousands	12 Months Ended
EMPLOYEE BENEFIT PLANS TEXTUALS (Details) $ in Thousands	Dec. 31, 2021 USD ($) numberOfPlans	Dec. 31, 2020 USD ($) numberOfPlans	Dec. 31, 2019 USD ($)
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, cost recognized	$ 54,700	$ 18,300	$ 22,900
Defined Benefit Plan, Description	Wesco sponsors a contributory defined benefit plan covering substantially all Canadian employees of EECOL Electric Corp., a wholly-owned subsidiary of the Company (the "EECOL Plan"). The EECOL Plan provides retirement benefits based on earnings and credited service, and participants contribute 2% of their earnings to the EECOL Plan. Participants become 100% vested after two years of continuous service or, if earlier, at the participant's normal retirement age.
Defined Benefit Plan, Unfunded Plan	Wesco also sponsors a Supplemental Executive Retirement Plan for certain executives of EECOL Electric Corp. (the "EECOL SERP"), which provides additional pension benefits based on earnings and credited service. The EECOL SERP is an unfunded plan. Effective January 1, 2013, the EECOL SERP was closed to new participants and existing participants became 100% vested. EECOL SERP participants now contribute 4% of their earnings to the EECOL Plan. Anixter Inc. sponsors various defined benefit pension plans in the U.S., which consist of the Anixter Inc. Pension Plan, the Anixter Inc. Executive Benefit Plan, and the Supplemental Executive Retirement Plan (the "Anixter SERP") (together, the "Domestic Plans") and various defined benefit pension plans covering employees of foreign subsidiaries in Canada and Europe (together with the "EECOL Plan" and "EECOL SERP", the "Foreign Plans").The Anixter Inc. Pension Plan was closed to entrants first hired or rehired on or after July 1, 2015. The majority of the Anixter defined benefit pension plans are non-contributory, and with the exception of the U.S. and Canada, cover substantially all full-time employees in their respective countries. Retirement benefits are provided based on compensation as defined in each of the plan agreements
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.60%	2.20%
Defined Benefit Plan, Benefit Obligation	$ 725,879	$ 819,339	134,852
DefinedBenefitPlanNumberOfPlansWithProjectedBenefitObligationsInExcessOfFairValueOfPlanAssets \| numberOfPlans	9	13
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	$ 214,500	$ 504,800
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets	167,400	365,400
Defined Benefit Plan, Plan Assets, Amount	$ 752,512	$ 721,005	103,385
DefinedBenefitPlanNumberOfPlansWithAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssets \| numberOfPlans	9	13
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	$ 194,600	$ 435,600
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets	167,400	365,400
Service Cost	$ 15,173	10,792	4,602
Defined Benefit Plan Assets Actual Gain Loss	6.00%
Defined Benefit Plan, Expected Future Benefit Payment, Year One	$ 20,645
Increase (Decrease) in Other Operating Assets	56,274	(2,321)	28,915
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	$ 36,580	0	0
WESCO [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	50.00%
Defined contribution plan, maximum annual contribution per employee, percent	6.00%
Defined contribution plan, employer discretionary contribution amount	$ 13,100
Anixter Employee Savings Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	50.00%
Defined contribution plan, maximum annual contribution per employee, percent	5.00%
WESCO Deferred Compensation Plan
Schedule of Employee Benefit Plans [Line Items]
Deferred Compensation Liability, Current and Noncurrent		27,400
Deferred Compensation Liability, Current		10,100
Deferred Compensation Liability, Classified, Noncurrent		17,300
AnixterDeferred Compensation Plan
Schedule of Employee Benefit Plans [Line Items]
Deferred Compensation Arrangement with Individual, Distribution Paid	$ 42,800
Deferred Compensation Liability, Current		45,100
Assets Held-in-trust		$ 39,600
Increase (Decrease) in Other Operating Assets	$ 39,700
Defined Contribution Pension Plan for Employees of Anixter Canada Inc.
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	6.00%
Defined contribution plan, maximum annual contribution per employee, percent	5.50%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	25.00%
Canadian Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	4.00%
U.S. Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	100.00%
Foreign Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.40%	2.00%
Defined Benefit Plan, Benefit Obligation	$ 424,096	$ 486,855	134,852
Defined Benefit Plan, Plan Assets, Amount	381,781	365,718	103,385
Accumulated Benefit Obligation (ABO) at December 31	390,800	417,600
Service Cost	12,140	9,029	4,602
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	10,800
Defined Benefit Plan, Expected Future Benefit Payment, Year One	9,430
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	$ 32,680	$ 0	0
United States
Schedule of Employee Benefit Plans [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.90%	2.60%
Defined Benefit Plan, Benefit Obligation	$ 301,783	$ 332,484	0
Defined Benefit Plan, Plan Assets, Amount	370,731	355,287	0
Accumulated Benefit Obligation (ABO) at December 31	301,800	328,200
Service Cost	3,033	1,763	0
Defined Benefit Plan, Expected Future Benefit Payment, Year One	11,215
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	$ 3,900	0	0
Minimum \| WESCO Distribution Canada Defined Contribution plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	3.00%
Defined Contribution Plan, Employer Matching Contribution greater than 20 years of service, Percent of Employees' Gross Pay	5.00%
Minimum \| Anixter Employee Savings Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution discretionary contribution percentage	2.00%
Minimum \| Defined Contribution Pension Plan for Employees of Anixter Canada Inc.
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	3.00%
Minimum \| Canadian Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	3.00%
Minimum \| U.S. Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	3.00%
Maximum \| WESCO Distribution Canada Defined Contribution plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	5.00%
Defined Contribution Plan, Employer Matching Contribution greater than 20 years of service, Percent of Employees' Gross Pay	7.00%
Maximum \| Anixter Employee Savings Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution discretionary contribution percentage	2.50%
Maximum \| Defined Contribution Pension Plan for Employees of Anixter Canada Inc.
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	4.00%
Maximum \| Canadian Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	5.00%
Maximum \| U.S. Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent	4.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Pension Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Other Nonoperating Gains (Losses)	$ (53,200)	(8,200)	$ (1,400)
Pension Plan [Member] \| Foreign Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined Benefit Plan, Benefit Obligation	424,100	$ 486,900
WESCO Deferred Compensation Plan
Schedule of Employee Benefit Plans [Line Items]
Deferred Compensation Liability, Classified, Noncurrent	$ 20,900