WESCO International (WCC) 10-K 25 Feb 22 2021 FY Annual report Financial data

COVER PAGE

COVER PAGE - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Feb. 24, 2022	Jun. 30, 2021
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-14989
Entity Registrant Name	WESCO International, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	25-1723342
Entity Address, Postal Zip Code	15219
Entity Address, Address Line One	225 West Station Square DriveSuite 700
Entity Address, State or Province	PA
Entity Address, City or Town	Pittsburgh,
City Area Code	412
Local Phone Number	454-2200
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 5.1
Entity Common Stock, Shares Outstanding		50,703,285
Entity Central Index Key	0000929008
Documents Incorporated by Reference	Part III of this Form 10-K incorporates by reference portions of the registrant’s Proxy Statement for its 2022 Annual Meeting of Stockholders.
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Class A [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $.01 per share
Trading Symbol	WCC
Name of Exchange	NYSE
Series A Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares, each representing a 1/100th interest in a share of Series A Fixed-Rate Reset Cumulative Perpetual Preferred Stock
Trading Symbol	WCC PR A
Name of Exchange	NYSE

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor [Line Items]
Auditor Location	Pittsburgh, Pennsylvania
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 212,583	$ 449,135
Trade accounts receivable	2,957,613	2,466,903
Other accounts receivable	375,885	239,199
Inventories	2,666,219	2,163,831
Prepaid expenses and other current assets	137,811	187,910
Total current assets	6,350,111	5,506,978
Property, buildings and equipment, net	379,012	399,157	[1]
Operating Lease, Right-of-Use Asset	530,863	534,705	[2]
Intangible assets, net	1,944,141	2,065,495
Goodwill	3,208,333	3,187,169
Deferred Income Taxes	34,191	37,696
Other assets	171,048	93,941
Assets Held-for-sale	0	55,073
Total assets	12,617,699	11,880,214
Current Liabilities:
Accounts payable	2,140,251	1,707,329
Accrued payroll and benefit costs	314,962	198,535
Short-term debt and current portion of long-term debt	9,528	528,830
Other current liabilities	585,067	552,301
Total current liabilities	3,049,808	2,986,995
Long-term Debt, Excluding Current Maturities	4,701,542	4,369,953
Operating Lease, Liability, Noncurrent	414,248	414,889	[2]
Deferred Income Tax Liabilities, Net	437,444	488,261
Other noncurrent liabilities	238,446	278,010
Liabilities Held for Sale	0	5,717
Total liabilities	8,841,488	8,543,825
Commitments and contingencies
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	20,000,000
Preferred stock, shares issued	21,612	21,612
Treasury stock, shares outstanding	22,026,922	21,870,961
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0	$ 0
Additional capital	1,969,332	1,942,810
Retained earnings	3,004,690	2,601,662
Treasury stock, at cost	(956,188)	(938,335)
Accumulated other comprehensive income (loss)	(236,035)	(263,134)
Total stockholders' equity	3,782,524	3,343,722
Noncontrolling interest	(6,313)	(7,333)
Total WESCO International stockholders' equity	3,776,211	3,336,389
Total liabilities and stockholders' equity	$ 12,617,699	$ 11,880,214
Common Stock
Current Liabilities:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	210,000,000	210,000,000
Common stock, shares issued	68,162,297	67,596,515
Common stock, shares outstanding	50,474,806	50,064,985
Stockholders' Equity:
Common Stock	$ 682	$ 676
Common Class B
Current Liabilities:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	4,339,431	4,339,431
Common stock, shares outstanding	0	0
Stockholders' Equity:
Common Stock	$ 43	$ 43
Preferred Stock
Current Liabilities:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares outstanding	0	0
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0	$ 0
Series A Preferred Stock
Current Liabilities:
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	25,000
Preferred stock, shares issued	21,612
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0	$ 0
[1]	The components of property, buildings and equipment as of December 31, 2020 exclude a total of $0.3 million that is classified as held for sale, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) The furniture, fixtures and equipment, and software costs components of property, buildings and equipment as of December 31, 2020 reflect a $6.4 million reclassification between the previously reported amounts of those components to conform to the current period's presentation.
[2]	Operating lease assets and liabilities of $1.9 million and $2.1 million, respectively, are classified as held for sale as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale".

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net sales	[1]	$ 18,217,512	$ 12,325,995	$ 8,358,917
Cost of goods sold (excluding depreciation and amortization below)		14,425,444	9,998,329	6,777,456
Selling, general and administrative expense		2,791,641	1,859,028	1,173,137
Depreciation and amortization		198,554	121,600	62,107
Income from operations		801,873	347,038	346,217
Interest expense, net		268,073	226,591	65,710
Other, net		(48,112)	(2,395)	(1,554)
Income before income taxes		581,912	122,842	282,061
Provision for income taxes		115,510	22,803	59,863
Net income		466,402	100,039	222,198
Net loss attributable to noncontrolling interest		1,020	(521)	(1,228)
Net Income attributable to WESCO International, Inc.		465,382	100,560	223,426
Preferred Stock Dividends, Income Statement Impact		57,408	30,139	0
Net Income (Loss) Available to Common Stockholders, Basic		407,974	70,421	223,426
Comprehensive Income:
Foreign currency translation adjustment		(15,584)	95,577	49,306
Benefit plan adjustments		42,683	9,061	(8,643)
Comprehensive income attributable to WESCO International, Inc.		$ 435,073	$ 175,059	$ 264,089
Earnings per share :
Basic		$ 8.11	$ 1.53	$ 5.18
Diluted		$ 7.84	$ 1.51	$ 5.14
[1]	(2) Wesco attributes revenues from external customers to individual countries on the basis of point of sale.

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Additional Capital	Retained Earnings (Deficit)	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest	Common Stock	Common Class B	Series A Preferred Stock
Common Stock							$ 592	$ 43
Common stock, shares issued							59,157,696	4,339,431
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0
Preferred stock, shares issued	0
Additional capital	$ 993,666
Retained earnings	2,307,462
Treasury stock, at cost	$ (758,018)
Treasury Stock, Shares	(18,391,042)
Noncontrolling interest	$ (5,584)
Accumulated other comprehensive income (loss)	(408,435)
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)				$ (238)			$ 1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period				3,730			198,985
APIC, Share-based Payment Arrangement, Recognition and Exercise	(84)
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture	19,062
Treasury Stock, Value, Acquired, Par Value Method		$ 28,901
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation		2,198	$ 459				$ 0
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation							48,663
Net Income attributable to WESCO International, Inc.	223,426
Translation adjustment					$ 49,306
Benefit plan adjustments, tax	(2,943)
Benefit plan adjustments, net of tax	8,643				(8,643)
Net loss attributable to noncontrolling interest	(1,228)					$ (1,228)
Treasury Stock, Value, Acquired, Cost Method	$ (178,901)
Treasury Stock, Shares, Acquired	(3,455,584)
Common Stock							$ 593	$ 43
Common stock, shares issued							59,308,018	4,339,431
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0
Preferred stock, shares issued	0
Additional capital	$ 1,039,347
Retained earnings	2,530,429
Treasury stock, at cost	$ (937,157)
Treasury Stock, Shares	(21,850,356)
Noncontrolling interest	$ (6,812)
Accumulated other comprehensive income (loss)	(367,772)
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)				$ (1,178)			$ 1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period				20,605			171,517
Stock Issued During Period, Value, Acquisitions		886,601					$ 82		$ 0
APIC, Share-based Payment Arrangement, Recognition and Exercise	(40)
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture	19,279
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation		2,377	(812)				$ 0
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation							33,248
Stock Issued During Period, Shares, Acquisitions							8,150,228		21,612
Net Income attributable to WESCO International, Inc.	100,560
Dividends, Preferred Stock	(30,139)
Translation adjustment					95,577
Benefit plan adjustments, tax	2,891
Benefit plan adjustments, net of tax	(9,061)				9,061
Net loss attributable to noncontrolling interest	(521)					(521)
Common Stock							$ 676	$ 43
Common stock, shares issued							67,596,515	4,339,431
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0								$ 0
Preferred stock, shares issued	21,612
Additional capital	$ 1,942,810
Retained earnings	2,601,662
Treasury stock, at cost	$ (938,335)
Treasury Stock, Shares	(21,870,961)
Noncontrolling interest	$ (7,333)
Accumulated other comprehensive income (loss)	(263,134)
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)				$ (17,853)			$ 7
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period				155,961			662,261
APIC, Share-based Payment Arrangement, Recognition and Exercise	(43)
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture	30,821
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation		$ 4,256	$ 4,946				$ (1)
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation							96,479
Net Income attributable to WESCO International, Inc.	465,382
Dividends, Preferred Stock	(57,408)
Translation adjustment					(15,584)
Benefit plan adjustments, tax	13,043
Benefit plan adjustments, net of tax	(42,683)				$ 42,683
Net loss attributable to noncontrolling interest	1,020					$ 1,020
Common Stock							$ 682	$ 43
Common stock, shares issued							68,162,297	4,339,431
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0								$ 0
Preferred stock, shares issued	21,612								21,612
Additional capital	$ 1,969,332
Retained earnings	3,004,690
Treasury stock, at cost	$ (956,188)
Treasury Stock, Shares	(22,026,922)
Noncontrolling interest	$ (6,313)
Accumulated other comprehensive income (loss)	$ (236,035)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stockholders' Equity Parenthetical [Abstract]
Benefit plan adjustments, tax	$ 13,043	$ 2,891	$ (2,943)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net income	$ 466,402	$ 100,039	$ 222,198
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	198,554	121,600	62,107
Stock-based compensation expense	30,821	19,279	19,062
Amortization of Debt Issuance Costs and Discounts	19,197	10,578	3,578
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	(36,580)	0	0
Gain (Loss) on Disposition of Business	(8,927)	(19,816)	0
Other operating activities, net	7,406	15,604	(14,753)
Deferred income taxes	(78,285)	(33,538)	13,205
Changes in assets and liabilities
Increase (Decrease) in Accounts Receivable	(531,828)	47,879	11,453
Increase (Decrease) in Accounts and Other Receivables	(136,659)	(23,520)	130
Inventories	(530,730)	203,827	(47,297)
Increase (Decrease) in Other Operating Assets	(56,274)	2,321	(28,915)
Accounts payable	(449,564)	54,127	(23,505)
Accrued payroll and benefit costs	84,204	75,556	(39,081)
Other current and noncurrent liabilities	190,273	78,249	(825)
Net cash provided by operating activities	67,138	543,931	224,367
Investing Activities:
Capital expenditures	(54,746)	(56,671)	(44,067)
Acquisition payments, net of cash acquired	0	(3,707,575)	(27,597)
Proceeds from Divestiture of Businesses, Net of Cash Divested	56,010	19,066	0
Proceeds from sale of assets	5,221	6,721	16,795
Other investing activities, net	(3,948)	3,310	(5,931)
Net cash used in investing activities	2,537	(3,735,149)	(60,800)
Financing Activities:
Proceeds from (Repayments of) Short-term Debt	(20,313)	(11,258)	(29,780)
Proceeds from issuance of long-term debt	3,231,443	5,114,210	1,305,421
Repayments of Long-term Debt	(2,565,142)	(1,513,048)	(1,217,434)
Payment, Tax Withholding, Share-based Payment Arrangement	(27,158)	(2,901)	(3,049)
Payments for Repurchase of Common Stock	0	0	(150,000)
Debt issuance costs	(2,280)	(80,231)	(2,707)
Payments of Dividends	(57,408)	(30,139)	0
Other financing activities, net	15,217	(4,108)	12,217
Net cash provided (used) by financing activities	(310,779)	3,480,741	(109,766)
Effect of exchange rate on cash and cash equivalents	4,552	8,710	758
Net change in cash and cash equivalents	(236,552)	298,233	54,559
Cash and cash equivalents at the beginning of period	449,135	150,902	96,343
Cash and cash equivalents at the end of period	212,583	449,135	150,902
Supplemental disclosures:
Cash paid for interest	249,654	169,620	65,275
Cash paid for taxes	118,183	56,186	64,531
Senior Notes Due 2021 [Member]
Repayments of Senior Debt	500,000	0	0
Financing Activities:
Repayments of Senior Debt	500,000	0	0
Senior Notes due 2024 [Member]
Repayments of Senior Debt	354,704	0	0
Financing Activities:
Repayments of Senior Debt	$ 354,704	$ 0	$ 0

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss	$ 41,723	$ 23,909
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ 70,572	87,142
Senior Notes Due 2021 [Member]
Debt Issuance Costs, Current, Net		$ 1,039

ORGANIZATION

ORGANIZATION	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION	WESCO International, Inc. ("Wesco International") and its subsidiaries (collectively, “Wesco” or the "Company"), headquartered in Pittsburgh, Pennsylvania, is a leading provider of business-to-business distribution, logistics services and supply chain solutions.The Company has operating segments that are organized around three strategic business units consisting of Electrical & Electronic Solutions ("EES"), Communications & Security Solutions ("CSS") and Utility & Broadband Solutions ("UBS")

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Basis of Presentation The consolidated financial statements include the accounts of Wesco International and all of its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Out-of-Period Adjustment In the fourth quarter of 2020, management determined that the Company’s inventories were overstated by $60.3 million because of a misstatement in inventory cost absorption accounting, which occurred over multiple periods and also impacted inventories acquired in business combinations during those periods. Accordingly, the Consolidated Balance Sheet at December 31, 2020 reflects a reduction to inventories of $60.3 million, an increase to goodwill of $33.9 million and a decrease to deferred income tax liabilities of $12.0 million. The resulting effect of the out-of-period adjustment on the Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2020 was a $18.9 million increase to cost of goods sold, which decreased net income for the year by $14.4 million. Management concluded that this misstatement was not material to the prior year or the financial statements of any previously filed annual or interim periods. Change in Estimates During the second quarter of 2021, the Company established a new corporate brand strategy that will result in migrating certain legacy sub-brands to a master brand architecture. The Company accounts for the trademarks associated with these sub-brands as intangible assets. As of December 31, 2020, $39.1 million of the trademarks impacted by the master brand strategy had indefinite lives and $9.5 million had remaining estimated useful lives ranging from 3 to 8 years. As disclosed further below, the Company continually evaluates whether events or circumstances have occurred that would require a change to the estimated useful lives of indefinite-lived and definite lived intangible assets. When such a change is warranted, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. Accordingly, during the second quarter of 2021, the Company changed the estimated useful lives of the trademarks affected by the new corporate brand strategy to coincide with the expected period of time to migrate such sub-brands to the master brand architecture. The Company assigned remaining estimated useful lives to these trademarks, including those that previously had indefinite lives, ranging from less than one year to 5 years. The Company assessed these intangible assets for impairment prior to amortizing them over their revised estimated remaining useful lives. No impairment losses were identified as a result of these tests. For the year ended December 31, 2021, the Company recognized $32.0 million of amortization expense resulting from these changes in estimated useful lives. Reclassifications The Consolidated Statements of Cash Flows for the years ended December 31, 2020 and 2019, respectively, include certain reclassifications to previously reported amounts to conform to the current period's presentation. Such reclassifications had no impact on the totals of operating, investing and financing cash flow activities for those years. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles in the United States of America requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates are based on management’s best knowledge of current events and actions Wesco may undertake in the future, actual results may ultimately differ from the estimates. Revenue Recognition Wesco’s revenue arrangements generally consist of single performance obligations to transfer a promised good or service, or a combination of goods and services. Revenue is measured as the amount of consideration Wesco expects to receive in exchange for transferring goods or providing services. Revenue is recognized when control has transferred to the customer, which is generally when the product has shipped from a Wesco facility or directly from a supplier. However, transfer may occur at a later date depending on the agreed upon terms, such as delivery at the customer's designated location, or based on consignment terms. For products that ship directly from suppliers to customers, Wesco acts as the principal in the transaction and recognizes revenue on a gross basis. When providing services, sales are recognized over time as control transfers to the customer, which occurs as services are rendered. Wesco generally satisfies its performance obligations within a year or less. Wesco generally does not have significant financing terms associated with its contractual arrangements; payments are normally received within 60 days. There are generally no significant costs associated with obtaining customer contracts. Wesco typically passes through warranties offered by manufacturers or suppliers to its customers. Sales taxes (and value added taxes in foreign jurisdictions) collected from customers and remitted to governmental authorities are excluded from net sales. Supplier Volume Rebates Wesco receives volume rebates from certain suppliers based on contractual arrangements with such suppliers. Volume rebates are included within other receivables in the Consolidated Balance Sheets, and represent the estimated amounts due to Wesco based on forecasted purchases and the rebate provisions of the various supplier contracts. The corresponding rebate income is recorded as a reduction to cost of goods sold. Receivables under the supplier rebate program were $219.1 million at December 31, 2021 and $136.7 million at December 31, 2020. The supplier volume rebate income as a percentage of net sales was 1.4% in 2021, 1.1% in 2020 and 1.2% in 2019. Cash Equivalents Cash equivalents are defined as highly liquid investments with original maturities of 90 days or less when purchased. Allowance for Expected Credit Losses Wesco recognizes expected credit losses resulting from the inability of its customers to make required payments through an allowance account that is measured each reporting period. Wesco estimates credit losses over the life of its trade accounts receivable using a combination of historical loss data, current credit conditions, specific customer circumstances, and reasonable and supportable forecasts of future economic conditions. The allowance for expected credit losses was $41.7 million at December 31, 2021 and $23.9 million at December 31, 2020. The total amount recorded as selling, general and administrative expense related to credit losses was $12.9 million, $10.1 million and $7.0 million for 2021, 2020 and 2019, respectively. Inventories Inventories primarily consist of merchandise purchased for resale and are stated at the lower of cost and net realizable value. Cost is determined principally under the average cost method. Wesco reduces the carrying value of its inventories at the earlier of identifying an item that is considered to be obsolete or in excess of supply relative to demand, or no movement in a prescribed number of months. Reserves for excess and obsolete inventories were $50.3 million and $28.7 million at December 31, 2021 and 2020, respectively. The total expense related to excess and obsolete inventories, which is included in cost of goods sold, was $37.1 million, $15.7 million and $10.0 million for 2021, 2020 and 2019, respectively. Property, Buildings and Equipment Property, buildings and equipment are recorded at cost. Depreciation expense is determined using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized over either their respective lease terms or their estimated lives, whichever is shorter. Estimated useful lives range from five to forty years for buildings and leasehold improvements and two to ten years for furniture, fixtures and equipment. Costs incurred during the application development stage of internally developed software are capitalized and are reported at the lower of unamortized cost or net realizable value. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Capitalized costs include external direct costs of materials and services consumed in developing internal-use computer software, payroll and payroll-related costs for employees who are directly associated with and who devote time to the internal-use computer software project, as well as interest costs. Internal-use computer software is amortized using the straight-line method over its estimated useful life, typically three to seven years. Expenditures for new facilities and improvements that extend the useful life of an asset are capitalized. Ordinary repairs and maintenance are expensed as incurred. When property is retired or otherwise disposed, the cost and the related accumulated depreciation are removed from the accounts and any resulting gains or losses are recorded and reported as selling, general and administrative expenses. Of Wesco’s $379.0 million net book value of property, buildings and equipment as of December 31, 2021, $133.6 million consists of land, buildings and leasehold improvements that are geographically dispersed among Wesco’s 800 branches, warehouses and sales offices, mitigating the risk of impairment. Wesco assesses its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of any such assets may not be fully recoverable. Changes in circumstances include technological advances, changes in the business model, capital structure, economic conditions or operating performance. The evaluation is based upon, among other things, utilization, serviceability and assumptions developed by management, which are categorized as Level 3 of the fair value hierarchy, related to the estimated future undiscounted cash flows that these assets are expected to generate. When the sum of the undiscounted cash flows is less than the carrying value of the asset (asset group), an impairment loss is recognized to the extent that carrying value exceeds fair value. Management applies its best judgment when performing these evaluations. Leases The determination of whether an arrangement is, or contains, a lease is performed at the inception of the arrangement. Classification and initial measurement of the right-of-use asset and lease liability are determined at the lease commencement date. The Company elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of 12 months or less are not recorded on the balance sheet. Operating lease expense is recognized on a straight-line basis over the lease term. Operating lease assets and liabilities are recognized at the commencement date based on the present value of the future minimum lease payments. Certain leases contain rent escalation clauses that are either fixed or adjusted periodically for inflation or market rates and such clauses are factored into the Company's determination of lease payments. Wesco also has variable lease payments that do not depend on a rate or index, primarily for items such as common area maintenance and real estate taxes, which are recorded as variable expense when incurred. The operating lease asset includes advance payments and excludes incentives and initial direct costs incurred. The Company's arrangements include certain non-lease components such as common area and other maintenance for leased real estate, as well as mileage, fuel and maintenance costs related to leased automobiles and trucks. Wesco accounts for these non-lease components separately from the associated lease components. The Company does not guarantee any residual value in its lease agreements, and there are no material restrictions or covenants imposed by lease arrangements. Real estate leases typically include one or more options to extend the lease, or terminate early. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term. For most of Wesco’s leases, the discount rate implicit in the lease is not readily determinable. Accordingly, the Company uses its incremental borrowing rate based on the information available at the lease commencement date to discount lease payments to the present value. Goodwill and Indefinite-Lived Intangible Assets Goodwill and indefinite-lived intangible assets are tested for impairment annually during the fourth quarter, or more frequently if triggering events occur, indicating that their carrying value may not be recoverable. Wesco tests for goodwill impairment on a reporting unit level. The Company first assesses qualitative factors, including macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, other relevant events such as changes in key personnel, changes in the composition or carrying amount of the net assets of a reporting unit, and changes in in share price, to determine whether it is more likely than not that the fair value of Wesco's reporting units are less than their carrying values. If the qualitative assessment indicates that the fair values of the Company's reporting units may not exceed their respective carrying values, then Wesco performs a quantitative test for impairment by comparing the fair value of each reporting unit to its carrying value. The Company determines the fair values of its reporting units using a discounted cash flow analysis and consideration of market multiples. The discounted cash flow analysis uses certain assumptions, including expected operating margins supported by a combination of historical results, current forecasts, market data and recent economic events, which are categorized within Level 3 of the fair value hierarchy. The Company uses a discount rate that reflects market participants' cost of capital. Wesco evaluates the recoverability of indefinite-lived intangible assets using the relief-from-royalty method based on projected financial information. Significant inputs used in the relief-from-royalty method include projected revenues, discount rates, royalty rates, and applicable income tax rates. At December 31, 2021 and 2020, goodwill and indefinite-lived trademarks totaled $4.0 billion. The determination of fair value involves significant management judgment, particularly as it relates to the underlying assumptions and factors around expected operating margins and discount rate. Management applies its best judgment when assessing the reasonableness of financial projections. Fair values are sensitive to changes in underlying assumptions and factors. As a result, there can be no assurance that the estimates and assumptions made for purposes of the annual goodwill and indefinite-lived intangible impairment tests will prove to be an accurate prediction of future results. Definite Lived Intangible Assets Definite lived intangible assets are amortized over 1 to 20 years. Certain customer relationships are amortized using an accelerated method whereas all other definite lived intangible assets subject to amortization use a straight-line method. In either case, the amortization method reflects the pattern in which the economic benefits of the respective assets are consumed or otherwise used. Wesco continually evaluates whether events or circumstances have occurred that would indicate the remaining estimated useful lives of definite lived intangible assets require revision or that the remaining carrying value of such assets may not be recoverable. Insurance Programs Wesco uses commercial insurance for auto, workers’ compensation, casualty and health claims, and information technology as a risk-reduction strategy to minimize catastrophic losses. The Company’s strategy involves large deductible policies where Wesco must pay all costs up to the deductible amount. Wesco estimates the reserve for these programs based on historical incident rates and costs. The assumptions included in developing this accrual include the period of time between the incurrence and payment of a claim. The total liability related to insurance programs was $30.6 million and $27.9 million at December 31, 2021 and 2020, respectively. Income Taxes Wesco accounts for income taxes under the asset and liability method, which requires the recognition of deferred income taxes for events that have future tax consequences. Under this method, deferred income taxes are recognized (using enacted tax laws and rates) based on the future income tax effects of differences in the carrying amounts of assets and liabilities for financial reporting and tax purposes. The effect of a tax rate change on deferred tax assets and liabilities is recognized in income in the period of change. Wesco recognizes deferred tax assets at amounts that are expected to be realized. To make such determination, management evaluates all positive and negative evidence, including but not limited to, prior, current and future taxable income, tax planning strategies and future reversals of existing taxable temporary differences. A valuation allowance is recognized if it is “more-likely-than-not” that some or all of a deferred tax asset will not be realized. Wesco regularly assesses the realizability of deferred tax assets. Wesco accounts for uncertainty in income taxes using a "more-likely-than-not" recognition threshold. Due to the subjectivity inherent in the evaluation of uncertain tax positions, the tax benefit ultimately recognized may materially differ from the estimate recognized in the consolidated financial statements. Wesco recognizes interest and penalties related to uncertain tax benefits as part of interest expense and income tax expense, respectively. The Tax Cuts and Jobs Act of 2017 (the “TCJA”) imposed a one-time tax on the deemed repatriation of undistributed foreign earnings (the “transition tax”). Except for a portion of foreign earnings previously taxed in the U.S. that can effectively be distributed without further material U.S. or foreign taxation, the Company continues to assert that the undistributed earnings of its foreign subsidiaries are indefinitely reinvested. To the extent the earnings of the Company's foreign subsidiaries are distributed in the form of dividends, such earnings may be subject to additional taxes. The Company believes that it is able to maintain a sufficient level of liquidity for its domestic operations and commitments without incurring any material tax cost to repatriate cash held by its foreign subsidiaries. The provisions of the TCJA also introduced U.S. taxation on certain global intangible low-taxed income ("GILTI"). Wesco has elected to account for GILTI tax as a component of income tax expense. Foreign Currency The local currency is the functional currency for most of the Company's operations outside the U.S. Assets and liabilities of these operations are translated to U.S. dollars at the exchange rate in effect at the end of each period. Income statement accounts are translated at an exchange rate that approximates the average for the period. Translation adjustments arising from the use of differing exchange rates from period to period are included as a component of other comprehensive income (loss) within stockholders’ equity. Gains and losses from foreign currency transactions are included in net income for the period. Defined Benefit Pension Plan Liabilities and expenses for defined benefit pension plans are determined using actuarial methodologies and incorporate significant assumptions, including the interest rate used to discount the future estimated cash flows, the expected long-term rate of return on plan assets, and several assumptions relating to the employee workforce (salary increases, retirement age, and mortality). Unrealized gains and losses related to the Company's defined benefit pension obligations are recognized as a component of other comprehensive income (loss) within stockholders' equity. Gains or losses resulting from plan amendments, curtailments, and settlements are recognized as a component of other non-operating income and expenses ("other, net") in the period of the remeasurement. Fair Value of Financial Instruments The Company measures the fair value of assets and liabilities on a recurring and nonrecurring basis according to a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of the fair value hierarchy are as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that are accessible at the measurement date; Level 2 inputs include inputs other than Level 1 that are observable, either directly or indirectly, and Level 3 inputs are unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to measurements involving significant unobservable inputs (Level 3). The Company measures the fair values of goodwill, intangible assets and property, buildings and equipment on a nonrecurring basis if required by impairment tests applicable to these assets, as described above. Other, net Other non-operating income and expenses ("other, net") primarily includes the non-service cost components of net periodic pension cost (benefit) and foreign exchange gains and losses. Recently Adopted Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which removes certain exceptions to the general principles of Accounting Standards Codification ("ASC") Topic 740, Income Taxes , and simplifies other aspects of accounting for income taxes. The amendments in this ASU were effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption was permitted in any interim or annual period, with any adjustments reflected as of the beginning of the fiscal year of adoption. The Company adopted this ASU in the first quarter of 2021. The adoption of this guidance did not have a material impact on the consolidated financial statements and notes thereto presented herein. Recently Issued Accounting Pronouncements In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , which requires contract assets and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance with ASC Topic 606, Revenue from Contracts with Customers , as if the acquirer had originated the contracts. The amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Management is currently evaluating the impact that the adoption of this accounting standard will have on its consolidated financial statements and notes thereto. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting , which provides optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendments in this Update are effective for all entities as of March 12, 2020 through December 31, 2022. Management does not expect the replacement of London Interbank Offered Rate (LIBOR) and the related adoption of the optional guidance under this accounting standard to have a material impact on the Company's consolidated financial statements and notes thereto. Other pronouncements issued by the FASB or other authoritative accounting standards groups with future effective dates are either not applicable or are not expected to be significant to Wesco’s financial position, results of operations or cash flows.

REVENUE

REVENUE	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Wesco distributes products and provides services to customers globally in various end markets within its business segments. The segments, which consist of EES, CSS, and UBS operate in the United States, Canada and various other international countries. The following tables disaggregate Wesco’s net sales by segment and geography for the periods presented: Year Ended December 31, (In thousands) 2021 2020 2019 Electrical & Electronic Solutions $ 7,621,263 $ 5,479,760 $ 4,860,541 Communications & Security Solutions 5,715,238 3,323,264 909,496 Utility & Broadband Solutions 4,881,011 3,522,971 2,588,880 Total by segment $ 18,217,512 $ 12,325,995 $ 8,358,917 Year Ended December 31, (In thousands) 2021 2020 2019 United States $ 13,157,866 $ 9,110,453 $ 6,234,119 Canada 2,747,187 1,892,321 1,647,066 Other International (1) 2,312,459 1,323,221 477,732 Total by geography (2) $ 18,217,512 $ 12,325,995 $ 8,358,917 (1) No individual country's net sales are greater than 10% of total net sales. (2) Wesco attributes revenues from external customers to individual countries on the basis of point of sale. Due to the terms of certain contractual arrangements, Wesco bills or receives payment from its customers in advance of satisfying the respective performance obligation. Such advance billings or payments are recorded as deferred revenue and recognized as revenue when the performance obligation has been satisfied and control has transferred to the customer, which is generally upon shipment. Deferred revenue is usually recognized within a year or less from the date of the advance billing or payment. At December 31, 2021 and 2020, $35.5 million and $24.3 million, respectively, of deferred revenue was recorded as a component of other current liabilities in the Consolidated Balance Sheets. The Company also has certain long-term contractual arrangements where revenue is recognized over time based on the cost-to-cost input method. As of December 31, 2021 and 2020, the Company had contract assets of $33.4 million and $19.4 million, respectively, resulting from contracts where the amount of revenue recognized exceeded the amount billed to the customer. Contract assets are recorded in the Consolidated Balance Sheets as a component of prepaid expenses and other current assets. 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, 2021, 2020 and 2019 by approximately $433.4 million, $269.5 million and $106.6 million, respectively. As of December 31, 2021 and 2020, the Company's estimated product return obligation was $38.8 million and $38.9 million, respectively. Billings to customers for shipping and handling are recognized in net sales. Wesco has elected to recognize shipping and handling costs as a fulfillment cost. Shipping and handling costs recorded as a component of selling, general and administrative expenses totaled $248.3 million, $149.3 million and $71.7 million for the years ended December 31, 2021, 2020 and 2019, respectively.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	The Company’s financial instruments primarily consist of cash and cash equivalents, accounts receivable, accounts payable, bank overdrafts, outstanding indebtedness, foreign currency forward contracts, and benefit plan assets. The fair value of the Company's benefit plan assets is disclosed in Note 14, "Employee Benefit Plans" and except for outstanding indebtedness and foreign currency forward contracts, the carrying value of the Company’s remaining financial instruments approximates fair value. The Company uses a market approach to determine the fair value of its debt instruments, utilizing quoted prices in active markets, interest rates and other relevant information generated by market transactions involving similar instruments. Therefore, the inputs used to measure the fair value of the Company's debt instruments are classified as Level 2 within the fair value hierarchy. The carrying value of Wesco's debt instruments with fixed interest rates was $2,880.7 million and $3,730.1 million as of December 31, 2021 and 2020, respectively. The estimated fair value of this debt was $3,118.0 million and $4,084.7 million as of December 31, 2021 and 2020, respectively. The reported carrying values of Wesco's other debt instruments, including those with variable interest rates, approximated their fair values as of December 31, 2021 and 2020. The Company purchases foreign currency forward contracts to minimize the effect of fluctuating foreign currency-denominated accounts on its earnings. The foreign currency forward contracts are not designated as hedges for accounting purposes. The Company's strategy is to negotiate terms for its derivatives and other financial instruments to be highly effective, such that the change in the value of the derivative offsets the impact of the underlying hedge. Its counterparties to foreign currency forward contracts have investment-grade credit ratings. The Company regularly monitors the creditworthiness of its counterparties to ensure no issues exist that could affect the value of its derivatives.
Derivatives and Fair Value	The Company purchases foreign currency forward contracts to minimize the effect of fluctuating foreign currency-denominated accounts on its earnings. The foreign currency forward contracts are not designated as hedges for accounting purposes. The Company's strategy is to negotiate terms for its derivatives and other financial instruments to be highly effective, such that the change in the value of the derivative offsets the impact of the underlying hedge. Its counterparties to foreign currency forward contracts have investment-grade credit ratings. The Company regularly monitors the creditworthiness of its counterparties to ensure no issues exist that could affect the value of its derivatives.The Company does not hedge 100% of its foreign currency-denominated accounts. In addition, the results of hedging can vary significantly based on various factors, such as the timing of executing foreign currency forward contracts versus the movement of currencies, as well as fluctuations in the account balances throughout each reporting period. The fair value of foreign currency forward contracts is based on the difference between the contract rate and the current price of a forward contract with an equivalent remaining term. The fair value of foreign currency forward contracts is measured using observable market information. These inputs are considered Level 2 in the fair value hierarchy. At December 31, 2021 and 2020, foreign currency forward contracts were revalued at then-current foreign exchange rates with the changes in valuation reflected directly in other non-operating expenses (income) in the Consolidated Statements of Income and Comprehensive Income offsetting the transaction gain (loss) recorded on foreign currency-denominated accounts. At December 31, 2021 and 2020, the gross and net notional amounts of foreign currency forward contracts outstanding were approximately $188.6 million and $111.9 million, respectively. While all of the Company's foreign currency forward contracts are subject to master netting arrangements with its counterparties, assets and liabilities related to these contracts are presented on a gross basis within the Consolidated Balance Sheets. The gross fair value of assets and liabilities related to foreign currency forward contracts were immaterial

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	5. GOODWILL AND INTANGIBLE ASSETS Goodwill The following table sets forth the changes in the carrying value of goodwill by reportable segment for the periods presented: EES CSS UBS Total (In thousands) Balance as of January 1, 2020 $ 573,447 $ 235,711 $ 949,882 $ 1,759,040 Adjustments to goodwill for acquisitions (Note 6) (1) (2) (3) 264,538 868,936 250,553 1,384,027 Foreign currency exchange rate changes 15,471 10,853 17,778 44,102 Balance as of December 31, 2020 $ 853,456 $ 1,115,500 $ 1,218,213 $ 3,187,169 Adjustments to goodwill for acquisitions (Note 6) (4) 1,124 8,603 4,215 13,942 Foreign currency exchange rate changes and other 6,378 (2,391) 3,235 7,222 Balance as of December 31, 2021 $ 860,958 $ 1,121,712 $ 1,225,663 $ 3,208,333 (1) Adjustments to goodwill include the final allocation of the purchase price paid to acquire SLS, as disclosed in Note 6, "Acquisitions and Disposals", which is reflected in the EES segment. (2) Adjustments to goodwill include an increase of $33.9 million resulting from the out-of-period adjustment related to inventory cost absorption accounting, as described in Note 2, "Accounting Policies", which affected the EES, CSS and UBS segments by $20.2 million, $2.0 million, and $11.7 million, respectively. (3) Adjustments to goodwill include $26.1 million that was classified as held for sale on the UBS segment as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale". Such amount was disposed in the first quarter of 2021 as part of the Canadian divestitures disclosed in Note 6, "Acquisitions and Disposals". (4) Includes the effect on goodwill of the adjustments to the assets acquired and liabilities assumed in the merger with Anixter since their initial measurement, as described in Note 6, "Acquisitions and Disposals". Intangible Assets The components of intangible assets are as follows: December 31, 2021 December 31, 2020 Life (in years) Gross Carrying Amount (1) Accumulated Amortization (1) Net Gross Carrying Amount (1) Accumulated Amortization (1) Net (In thousands) Intangible assets: Trademarks (2) Indefinite $ 795,065 $ — $ 795,065 $ 833,793 $ — $ 833,793 Customer relationships (3) 10 - 20 1,431,251 (308,180) 1,123,071 1,434,554 (227,585) 1,206,969 Distribution agreements (3) 15 - 19 29,212 (22,714) 6,498 29,212 (21,040) 8,172 Trademarks (2)(3) 1 - 12 38,758 (20,058) 18,700 24,898 (11,415) 13,483 Non-compete agreements 2 4,300 (3,493) 807 4,462 (1,384) 3,078 $ 2,298,586 $ (354,445) $ 1,944,141 $ 2,326,919 $ (261,424) $ 2,065,495 (1) Excludes the original cost and related accumulated amortization of fully-amortized intangible assets. (2) As disclosed in Note 2, "Accounting Policies", the Company assigned remaining estimated useful lives to certain trademarks, including those that previously had indefinite lives. (3) The net carrying amount as of December 31, 2020 excluded $1.0 million of trademarks, $3.3 million of customer relationships and $1.4 million of distribution agreements that were classified as held for sale and disposed in the first quarter of 2021 as part of the Canadian divestitures disclosed in Note 7, "Assets and Liabilities Held For Sale". Amortization expense related to intangible assets totaled $119.6 million, $66.5 million and $35.5 million for the years ended December 31, 2021, 2020 and 2019, respectively. For the year ended December 31, 2021, amortization expense includes $32.0 million resulting from the changes in estimated useful lives of certain legacy trademarks that are migrating to the Company's master brand architecture, as described in Note 2, "Accounting Policies". The following table sets forth the remaining estimated amortization expense for intangible assets for the next five years and thereafter: For the year ending December 31, (In thousands) 2022 $ 92,593 2023 83,287 2024 80,827 2025 77,710 2026 60,834 Thereafter 753,825 The Company performed its annual impairment tests of goodwill and indefinite-lived intangible assets during the fourth quarter of 2021 by assessing qualitative factors to determine whether it was more likely than not that the fair values of its reporting units and indefinite-lived intangible assets were less than their respective carrying amounts. In performing this qualitative assessment, the Company assessed relevant events and circumstances, including macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, other relevant events such as changes in key personnel, changes in the composition or carrying amount of the net assets of a reporting unit, and changes in share price. As a result of this assessment, the Company determined that it was more likely than not that the fair values of its reporting units and indefinite-lived intangible assets continued to exceed their respective carrying amounts and, therefore, a quantitative impairment test was unnecessary. The annual impairment tests of goodwill and indefinite-lived intangible assets involve the assessment of factors, events and circumstances at a point in time that are subject to change. As a result, there can be no assurance that the fair values of the Company's reporting units and indefinite-lived intangible assets will exceed their carrying values in the future, and that goodwill and indefinite-lived intangible assets will be fully recoverable.

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
ACQUISITIONS	Anixter International Inc. On June 22, 2020, Wesco completed its acquisition of Anixter International Inc. ("Anixter"), a Delaware corporation. Pursuant to the terms of the Agreement and Plan of Merger, dated January 10, 2020 (the “Merger Agreement”), by and among Anixter, Wesco and Warrior Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Wesco (“Merger Sub”), Merger Sub was merged with and into Anixter (the “Merger”), with Anixter surviving the Merger and continuing as a wholly owned subsidiary of Wesco. On June 23, 2020, Anixter merged with and into Anixter Inc., with Anixter Inc. surviving to become a wholly owned subsidiary of Wesco. The Company used the net proceeds from the issuance of senior unsecured notes, borrowings under its revolving credit and accounts receivable securitization facilities (as described further in Note 10, "Debt"), as well as cash on hand, to finance the acquisition of Anixter and related transaction costs. At the effective time of the Merger, each outstanding share of common stock of Anixter (subject to limited exceptions) was converted into the right to receive (i) $72.82 in cash, (ii) 0.2397 shares of common stock of Wesco, par value $0.01 per share and (iii) 0.6356 depositary shares, each representing a 1/1,000th interest in a share of newly issued fixed-rate reset cumulative perpetual preferred stock of Wesco, Series A, with a $25,000 stated amount per whole preferred share and an initial dividend rate equal to 10.625%. Anixter was a leading distributor of network and security solutions, electrical and electronic solutions, and utility power solutions with locations in over 300 cities across approximately 50 countries, and 2019 annual sales of more than $8 billion. The Merger brought together two companies with highly compatible capabilities and characteristics. The combination of Wesco and Anixter created an enterprise with scale and has afforded the Company the opportunity to digitize its business and expand its services portfolio and supply chain offerings. The total fair value of consideration transferred for the Merger consisted of the following: (In thousands) Cash portion attributable to common stock outstanding $ 2,476,010 Cash portion attributable to options and restricted stock units outstanding 87,375 Fair value of cash consideration 2,563,385 Common stock consideration 313,512 Series A preferred stock consideration 573,786 Fair value of equity consideration 887,298 Extinguishment of Anixter obligations, including accrued and unpaid interest 1,247,653 Total purchase consideration $ 4,698,336 Supplemental cash flow disclosure related to acquisitions: Cash paid for acquisition $ 3,811,038 Less: Cash acquired (103,463) Cash paid for acquisition, net of cash acquired $ 3,707,575 The Merger was accounted for as a business combination with Wesco acquiring Anixter in accordance with ASC 805, Business Combinations . Under the acquisition method of accounting, the purchase consideration was allocated to the identified assets acquired and liabilities assumed based on their respective acquisition date fair value, with any excess allocated to goodwill. The fair value estimates were based on income, market and cost valuation methods using primarily unobservable inputs developed by management, which are categorized as Level 3 in the fair value hierarchy. Specifically, the fair values of the identified trademark and customer relationship intangible assets were estimated using the relief-from-royalty and multi-period excess earnings methods, respectively. Significant inputs used to value these identifiable intangible assets included projected revenues and expected operating margins, customer attrition rates, discount rates, royalty rates, and applicable income tax rates. The excess purchase consideration recorded as goodwill is not deductible for income tax purposes, and has been assigned to the Company's reportable segments based on their relative fair values, as disclosed in Note 5, "Goodwill and Intangible Assets". The resulting goodwill is primarily attributable to Anixter's workforce, significant cross-selling opportunities in additional geographies, enhanced scale, and other operational efficiencies. During the second quarter of 2021, the Company finalized its allocation of the purchase consideration to the respective fair values of assets acquired and liabilities assumed in the acquisition of Anixter. As the Company obtained additional information during the measurement period, it recorded adjustments to its preliminary estimates of fair value, which were as of June 30, 2020. As presented in the table below, the net impact of these measurement period adjustments was an increase to goodwill of $16.4 million. The following table sets forth the allocation of the purchase consideration to the respective fair value of assets acquired and liabilities assumed for the acquisition of Anixter: Preliminary Fair Value Estimates (1) Measurement Period Adjustments Final Purchase Price Allocation (1) Assets (In thousands) Cash and cash equivalents $ 103,463 $ — $ 103,463 Trade accounts receivable 1,309,894 (8,928) 1,300,966 Other receivables 116,386 — 116,386 Inventories 1,424,768 (14,906) 1,409,862 Prepaid expenses and other current assets 53,462 14,202 67,664 Property, buildings and equipment 215,513 (3,792) 211,721 Operating lease assets 262,238 18,047 280,285 Intangible assets 1,832,700 5,365 1,838,065 Goodwill 1,367,981 16,356 1,384,337 Other assets 114,258 25,589 139,847 Total assets $ 6,800,663 $ 51,933 $ 6,852,596 Liabilities Accounts payable $ 920,163 $ (1,239) $ 918,924 Accrued payroll and benefit costs 69,480 — 69,480 Short-term debt and current portion of long-term debt 13,225 — 13,225 Other current liabilities 221,574 12,745 234,319 Long-term debt 77,822 (205) 77,617 Operating lease liabilities 200,286 17,017 217,303 Deferred income taxes 392,165 (15,111) 377,054 Other noncurrent liabilities 207,612 38,726 246,338 Total liabilities $ 2,102,327 $ 51,933 $ 2,154,260 Fair value of net assets acquired, including goodwill and intangible assets $ 4,698,336 $ — $ 4,698,336 (1) The preliminary fair value estimates are as of June 30, 2020. As disclosed above, the Company finalized its purchase price allocation during the measurement period. The following table sets forth the identifiable intangible assets and their estimated weighted-average useful lives: Identifiable Intangible Assets Estimated Weighted-Average Estimated Useful Life in Years (In thousands) Customer relationships $ 1,098,900 19 Trademarks 735,000 Indefinite Non-compete agreements 4,165 2 Total identifiable intangible assets $ 1,838,065 The results of operations of Anixter are included in the consolidated financial statements beginning on June 22, 2020, the acquisition date. For the years ended December 31, 2021 and 2020, the consolidated statements of income include $9.5 billion and $4.5 billion of net sales, respectively, and $580.6 million and $180.0 million of income from operations, respectively, for Anixter. For the years ended December 31, 2021 and 2020, the Company incurred costs related to the Merger of $158.5 million and $132.2 million, respectively, which primarily consist of advisory, legal, integration, separation and other costs. These costs are included in selling, general and administrative expenses for both periods. Pro Forma Financial Information The following unaudited pro forma financial information presents combined results of operations for the periods presented, as if the Company had completed the Merger on January 1, 2019. The unaudited pro forma financial information includes adjustments to amortization and depreciation for intangible assets and property, buildings and equipment, adjustments to interest expense for the additional indebtedness incurred to complete the acquisition (including the amortization of debt discount and issuance costs), transaction costs, change in control and severance costs, dividends accrued on the Series A preferred stock, compensation expense associated with the Wesco phantom stock unit awards described in Note 14, "Employee Benefit Plans", as well as the respective income tax effects of such adjustments. For the year ended December 31, 2020, adjustments totaling $7.0 million increased the unaudited pro forma net income attributable to common stockholders, and adjustments totaling $201.3 million decreased the unaudited pro forma net income attributable to common stockholders for the year ended December 31, 2019. The unaudited pro forma financial information does not reflect any cost savings, operating synergies or revenue enhancements that Wesco may achieve as a result of its acquisition of Anixter, the costs to integrate the operations of Wesco and Anixter or the costs necessary to achieve these cost savings, operating synergies and revenue enhancements. The unaudited pro forma financial information presented below is not necessarily indicative of consolidated results of operations of the combined business had the acquisition occurred at the beginning of the respective periods, nor is it necessarily indicative of future results of operations of the combined company. Year Ended (In thousands) December 31, 2020 December 31, 2019 Pro forma net sales $ 16,016,902 $ 17,204,472 Pro forma net income attributable to common stockholders 119,839 285,100 Canadian Divestitures On August 6, 2020, the Company entered into a Consent Agreement with the Competition Bureau of Canada regarding the merger with Anixter. Under the Consent Agreement, the Company was required to divest certain legacy Wesco utility and data communications businesses in Canada, which had total net sales of approximately $110 million and $120 million for the years ended December 31, 2020 and 2019, respectively. In February 2021, the Company completed such divestitures for cash consideration totaling $56.0 million. The Company recognized a net gain from the sale of these businesses of $8.9 million, which is reported as a component of selling, general and administrative expenses for the year ended December 31, 2021. These dispositions fulfilled the Company’s divestiture commitments under the Consent Agreement and the net cash proceeds were used to repay debt.

ASSETS AND LIABILITIES HELD FOR

ASSETS AND LIABILITIES HELD FOR SALE	12 Months Ended
	Dec. 31, 2021
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure	On August 6, 2020, the Company entered into a Consent Agreement with the Competition Bureau of Canada regarding the merger with Anixter. Under the Consent Agreement, the Company agreed to divest certain legacy Wesco businesses in Canada. Accordingly, the Company determined that the assets and liabilities of these legacy Wesco businesses in Canada met the held for sale criteria as of December 31, 2020. These businesses did not meet the criteria to be classified as discontinued operations. As disclosed in Note 6, "Acquisitions and Disposals", the Company completed these divestitures in February 2021. The assets and liabilities classified as held for sale were as follows: As of December 31, 2020 (In thousands) Trade accounts receivable, net $ 4,258 Inventories 16,438 Prepaid expenses and other current assets 395 Property, buildings and equipment, net 263 Operating lease assets 1,938 Intangible assets, net 5,722 Goodwill 26,059 Total assets held for sale $ 55,073 Accounts payable $ 3,639 Other current liabilities 541 Operating lease liabilities 1,537 Total liabilities held for sale $ 5,717

PROPERTY, BUILDINGS AND EQUIPME

PROPERTY, BUILDINGS AND EQUIPMENT	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
PROPERTY, BUILDINGS AND EQUIPMENT	8. PROPERTY, BUILDINGS AND EQUIPMENT The following table sets forth the components of property, buildings and equipment: As of December 31, 2021 2020 (1) (In thousands) Buildings and leasehold improvements $ 165,691 $ 169,873 Furniture, fixtures and equipment (2) 281,864 272,704 Software costs (2) 250,447 229,279 698,002 671,856 Accumulated depreciation and amortization (365,345) (312,106) 332,657 359,750 Land 25,600 26,409 Construction in progress 20,755 12,998 $ 379,012 $ 399,157 (1) The components of property, buildings and equipment as of December 31, 2020 exclude a total of $0.3 million that is classified as held for sale, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) The furniture, fixtures and equipment, and software costs components of property, buildings and equipment as of December 31, 2020 reflect a $6.4 million reclassification between the previously reported amounts of those components to conform to the current period's presentation. Depreciation expense was $61.6 million, $40.8 million and $15.9 million, and capitalized software amortization was $27.5 million, $14.3 million and $10.6 million, in 2021, 2020 and 2019, respectively. As of December 31, 2021 and 2020, unamortized software costs were $103.4 million and $117.5 million, respectively. Furniture, fixtures and equipment include finance leases of $31.9 million and $25.7 million and related accumulated depreciation of $12.4 million and $7.9 million as of December 31, 2021 and 2020, respectively. The Company capitalizes costs associated with implementing its various cloud computing arrangements. Capitalized implementation costs, which are recorded as a component of other assets in the Consolidated Balance Sheets, were $39.6 million and $8.8 million as of December 31, 2021 and 2020, respectively, and the related accumulated amortization was $2.0 million and $1.1 million, respectively.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Lessee, Operating Leases	9. LEASES Wesco leases substantially all of its real estate, as well as automobiles, trucks, information technology hardware, and other equipment under lease arrangements classified as operating. The Company's finance leases, which are recorded in the Consolidated Balance Sheets as a component of property, buildings and equipment, current portion of long-term debt and long-term debt, are not material to the consolidated financial statements and notes thereto. Accordingly, finance leases have not been disclosed herein. The following table sets forth supplemental balance sheet information related to operating leases for the periods presented: As of December 31, (In thousands) 2021 2020 (1) Operating lease assets $ 530,863 $ 534,705 Current operating lease liabilities (2) 129,881 128,322 Noncurrent operating lease liabilities 414,248 414,889 Total operating lease liabilities $ 544,129 $ 543,211 (1) Operating lease assets and liabilities of $1.9 million and $2.1 million, respectively, are classified as held for sale as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) Current operating lease liabilities are recorded as a component of other current liabilities in the Consolidated Balance Sheets. The following table sets forth the Company's total lease cost, which is recorded as a component of selling, general and administrative expenses, for the periods presented: Year Ended December 31, (In thousands) 2021 2020 2019 Operating lease cost $ 169,892 $ 127,725 $ 73,613 Short-term lease cost 3,578 494 90 Variable lease cost 49,464 36,230 23,385 Total lease cost $ 222,934 $ 164,449 $ 97,088 Variable lease cost consists of the non-lease components described in Note 2, "Accounting Policies", as well as taxes and insurance for Wesco's leased real estate. The following table sets forth supplemental cash flow information related to operating leases for the periods presented: Year Ended December 31, (In thousands) 2021 2020 2019 Operating cash flows from operating leases $ 153,626 $ 117,106 $ 75,775 Right-of-use assets obtained in exchange for new operating lease liabilities 157,523 121,207 60,586 As of December 31, 2021 and 2020, the weighted-average remaining lease term for operating leases was 6.0 years and 6.1 years, respectively. The weighted-average discount rate used to measure operating leases was 4.2% and 4.6% as of December 31, 2021 and 2020, respectively. The following table sets forth the maturities of the Company's operating lease liabilities and reconciles the respective undiscounted payments to the operating lease liabilities in the Consolidated Balance Sheet as of December 31, 2021: (In thousands) 2022 $ 152,919 2023 126,012 2024 94,494 2025 64,875 2026 48,813 Thereafter 136,123 Total undiscounted operating lease payments 623,236 Less: imputed interest (79,107) Total operating lease liabilities $ 544,129 Operating lease payments include $26.9 million related to options to extend lease terms that are reasonably certain of being exercised. As of December 31, 2021, the Company has additional leases related to facilities that have not yet commenced of $67.1 million. These operating leases, which are not recorded in the Consolidated Balance Sheet as of December 31, 2021, will commence in 2022 with lease terms of 1.5 to 10.5 years.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	The following table sets forth Wesco’s outstanding indebtedness: As of December 31, 2021 2020 (In thousands) International lines of credit $ 7,354 $ 29,575 Accounts Receivable Securitization Facility 1,270,000 950,000 Revolving Credit Facility 596,959 250,000 5.375% Senior Notes due 2021 — 500,000 5.50% Anixter Senior Notes due 2023 58,636 58,636 5.375% Senior Notes due 2024 — 350,000 6.00% Anixter Senior Notes due 2025 4,173 4,173 7.125% Senior Notes due 2025 1,500,000 1,500,000 7.250% Senior Notes due 2028, less debt discount of $8,088 and $9,332 in 2021 and 2020, respectively 1,316,912 1,315,668 Finance lease obligations 18,563 17,931 Total debt 4,772,597 4,975,983 Plus: Fair value adjustments to the Anixter Senior Notes 957 1,650 Less: Unamortized debt issuance costs (62,484) (78,850) Less: Short-term debt and current portion of long-term debt (9,528) (528,830) Total long-term debt $ 4,701,542 $ 4,369,953 International Lines of Credit Certain foreign subsidiaries of Wesco have entered into uncommitted lines of credit, some of which are overdraft facilities, to support local operations. The maximum borrowing limit varies by facility and ranges between $0.6 million and $31.0 million. The international lines of credit generally are renewable on an annual basis and certain facilities are fully and unconditionally guaranteed by Wesco Distribution. Accordingly, certain borrowings under these lines directly reduce availability under its revolving credit facility. The applicable interest rate for borrowings under these lines of credit varies by country and is governed by the applicable loan agreement. The average interest rate for these facilities was 3.35% and 3.40% at December 31, 2021 and 2020, respectively. Accounts Receivable Securitization Facility On June 22, 2020, Wesco Distribution amended its accounts receivable securitization facility (the “Receivables Facility”) pursuant to the terms and conditions of a Fifth Amended and Restated Receivables Purchase Agreement (the “Receivables Purchase Agreement”), by and among WESCO Receivables Corp. (“Wesco Receivables”), Wesco Distribution, the various purchaser groups from time to time party thereto and PNC Bank, National Association, as Administrator. The Receivables Purchase Agreement amended and restated the receivables purchase agreement entered into on September 24, 2015 (the “Prior Receivables Purchase Agreement”). The Receivables Purchase Agreement, among other things, increased the purchase limit under the Prior Receivables Purchase Agreement from $600 million to $1,025 million, with the opportunity to exercise an accordion feature that permits increases in the purchase limit up to an aggregate commitment of $1,400 million, subject to customary conditions, extended the maturity date to June 22, 2023 and added and amended certain defined terms. Borrowings under the Receivables Facility bear interest at the 30-day LIBOR rate, with a LIBOR floor, plus applicable spreads. The interest rate spread under the Receivables Purchase Agreement of 1.20% increased from 0.95% under the Prior Receivables Purchase Agreement. The Receivables Facility has a commitment fee of 0.45%. On December 14, 2020, Wesco Distribution amended its Receivables Facility pursuant to the terms and conditions of a First Amendment to the Fifth Amended and Restated Receivables Purchase Agreement (the “First Receivables Amendment”). The First Receivables Amendment amended the Receivables Purchase Agreement and permitted an increase to the purchase limit from $1,025 million to $1,200 million. The maturity date, interest rate spread, and commitment fee of the Receivables Facility remained unchanged. On June 1, 2021, Wesco Distribution amended its Receivables Facility pursuant to the terms and conditions of a Third Amendment to the Fifth Amended and Restated Receivables Purchase Agreement (the “Third Receivables Amendment”). The Third Receivables Amendment, among other things, increased the purchase limit under the Receivables Purchase Agreement from $1,200 million to $1,300 million, increased the aggregate commitment under the accordion feature from $1,400 million to $1,500 million, extended the maturity date from June 22, 2023 to June 21, 2024, decreased the LIBOR floor from 0.50% to 0.00% and decreased the interest rate spread from 1.20% to 1.15%. The commitment fee of the Receivables Facility remained unchanged. Under the Receivables Facility, Wesco sells, on a continuous basis, an undivided interest in all domestic accounts receivable to Wesco Receivables, a wholly owned special purpose entity (the “SPE”). The SPE sells, without recourse, a senior undivided interest in the receivables to financial institutions for cash while maintaining a subordinated undivided interest in the receivables, in the form of overcollateralization. Since Wesco maintains control of the transferred receivables, the transfers do not qualify for “sale” treatment. As a result, the transferred receivables remain on the balance sheet, and Wesco recognizes the related secured borrowing. Wesco has agreed to continue servicing the sold receivables for the third-party conduits and financial institutions at market rates; accordingly, no servicing asset or liability has been recorded. As of December 31, 2021 and 2020, accounts receivable eligible for securitization totaled $1,728.1 million and $1,476.1 million, respectively. The Consolidated Balance Sheets as of December 31, 2021 and 2020 include $1,270.0 million and $950.0 million, respectively, of accounts receivable balances legally sold to third parties, as well as borrowings for equal amounts. At December 31, 2021, the interest rate for this facility was approximately 1.23%. Revolving Credit Facility On June 22, 2020, Wesco, Wesco Distribution and certain other subsidiaries of Wesco entered into a $1,100 million revolving credit facility (the “Revolving Credit Facility”), as a replacement of Wesco Distribution’s revolving credit facility entered into on September 26, 2019, pursuant to the terms and conditions of a Fourth Amended and Restated Credit Agreement, dated as of June 22, 2020 (the “Revolving Credit Agreement”), among Wesco Distribution, the other U.S. borrowers party thereto (collectively, the “U.S. Borrowers”), WESCO Distribution Canada LP (“Wesco Canada”), the other Canadian borrowers party thereto (collectively, the “Canadian Borrowers”), Wesco, the lenders party thereto and Barclays Bank PLC, as the administrative agent. The Revolving Credit Facility contains a letter of credit sub-facility of up to $175 million and an accordion feature allowing Wesco Distribution to request increases to the borrowing commitments under the Revolving Credit Facility of up to $500 million in the aggregate, subject to customary conditions. The Revolving Credit Facility matures in June 2025. On December 14, 2020, Wesco Distribution and certain other subsidiaries of Wesco entered into an amendment to the Revolving Credit Facility pursuant to the terms and conditions of a First Amendment to Fourth Amended and Restated Credit Agreement, dated as of December 14, 2020 (the “Revolver Amendment”), among Wesco Distribution, the other U.S. borrowers party thereto, WESCO Distribution Canada LP, the other Canadian borrowers party thereto, Wesco, the lenders party thereto and Barclays Bank PLC, as administrative agent. The Revolver Amendment increased the revolving commitments from $1,100 million to $1,200 million and amended certain other defined terms. No other material terms were changed. The obligations of Wesco Distribution and the other U.S. Borrowers under the Revolving Credit Facility have been guaranteed by Wesco and certain of Wesco Distribution’s subsidiaries (including certain subsidiaries of Anixter). The obligations of Wesco Canada and the other Canadian Borrowers under the Revolving Credit Facility (including certain subsidiaries of Anixter) have been guaranteed by certain subsidiaries of Wesco Canada and the other Canadian Borrowers. The Revolving Credit Facility is secured by (i) substantially all assets of Wesco Distribution, the other U.S. Borrowers and certain of Wesco Distribution’s subsidiaries (including certain subsidiaries of Anixter), other than, among other things, real property and accounts receivable sold or intended to be sold pursuant to the Receivables Facility, and (ii) substantially all assets of Wesco Canada, the other Canadian Borrowers and certain of Wesco Canada’s subsidiaries, other than, among other things, real property, in each case, subject to customary exceptions and limitations. The applicable interest rate for borrowings under the Revolving Credit Facility includes interest rate spreads based on available borrowing capacity that range between 1.25% and 1.50% for LIBOR-based borrowings and 0.25% and 0.50% for prime rate-based borrowings. At December 31, 2021, the interest rate for this facility was approximately 1.54%. The Revolving Credit Agreement requires compliance with conditions that must be satisfied prior to any borrowing as well as ongoing compliance with certain customary affirmative and negative covenants. The Revolving Credit Agreement contains customary events of default. Upon the occurrence and during the continuance of an event of default, the commitments of the lenders may be terminated, and all outstanding obligations of the loan parties under the Revolving Credit Facility may be declared immediately due and payable. During 2021, Wesco borrowed $2,353.4 million under the Revolving Credit Facility and made repayments in the aggregate amount of $2,006.4 million. During 2020, aggregate borrowings and repayments under the prior and new revolving credit facilities were $1,197.9 million and $948.0 million, respectively. Wesco had $564.8 million available under the Revolving Credit facility at December 31, 2021, after giving effect to outstanding letters of credit and certain borrowings under the Company's international lines of credit, as compared to $801.5 million available under the Revolving Credit Facility at December 31, 2020, after giving effect to outstanding letters of credit and certain borrowings under the Company's international lines of credit. 5.375% Senior Notes due 2021 In November 2013, Wesco Distribution issued $500 million aggregate principal amount of 5.375% Senior Notes due 2021 (the "2021 Notes") through a private offering exempt from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”). The 2021 Notes were issued at 100% of par and were governed by an indenture (the “2021 Indenture”) entered into on November 26, 2013 between Wesco Distribution, as issuer, and U.S. Bank National Association, as trustee. The 2021 Notes were unsecured senior obligations of Wesco Distribution and were guaranteed on a senior unsecured basis by Wesco International. The 2021 Notes had a stated interest rate of 5.375% per annum, payable semi-annually in arrears on June 15 and December 15 of each year. The 2021 Notes had a maturity date of December 15, 2021 and were redeemable in whole or in part at any time. The net proceeds of the 2021 Notes were used to prepay a portion of the U.S. sub-facility of the then outstanding term loan due 2019. Under the terms of a registration rights agreement dated as of November 26, 2013 among Wesco Distribution, Wesco International and Merrill Lynch, Pierce, Fenner & Smith Incorporated, as the representative of the initial purchasers of the 2021 Notes, Wesco Distribution and Wesco International agreed to register under the Securities Act notes having terms identical in all material respects to the 2021 Notes (the “2021 Exchange Notes”) and to make an offer to exchange the 2021 Exchange Notes for the 2021 Notes. Wesco Distribution launched the exchange offer on June 12, 2014 and the exchange offer expired on July 17, 2014. On December 15, 2020, Wesco Distribution exercised its right to redeem the entire $500 million aggregate principal amount of the 2021 Notes, and U.S. Bank, National Association, as trustee under the 2021 Indenture, issued a notice of redemption to registered holders of the 2021 Notes. On January 14, 2021, Wesco Distribution redeemed the $500 million aggregate principal amount of the 2021 Notes at a redemption price equal to 100% of the principal amount plus accrued interest to, but not including, January 14, 2021. The redemption of the 2021 Notes was funded with available cash, as well as borrowings under the Company's Receivables Facility and Revolving Credit Facility. The Company recognized a loss of $1.0 million from the redemption of the 2021 Notes resulting from the write-off of unamortized debt issuance costs, which is recorded as a component of interest expense in the Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2021. 5.375% Senior Notes due 2024 In June 2016, Wesco Distribution issued $350 million aggregate principal amount of 5.375% Senior Notes due 2024 (the "2024 Notes") through a private offering exempt from the registration requirements of the Securities Act. The 2024 Notes were issued at 100% of par and were governed by an indenture (the “2024 Indenture”) entered into on June 15, 2016 among Wesco Distribution, as issuer, Wesco International, as parent guarantor, and U.S. Bank National Association, as trustee. The 2024 Notes were unsecured senior obligations of Wesco Distribution and were guaranteed on a senior unsecured basis by Wesco International. The 2024 Notes had a stated interest rate of 5.375% per annum, payable semi-annually in arrears on June 15 and December 15 of each year. The 2024 Notes had a maturity date of June 15, 2024. The Company used the net proceeds from the 2024 Notes to redeem its 6.0% Convertible Senior Debentures due 2029. Under the terms of a registration rights agreement dated as of June 15, 2016 among Wesco Distribution, as the issuer, Wesco International, as parent guarantor, and Goldman, Sachs & Co., as representative of the initial purchasers of the 2024 Notes, Wesco Distribution and Wesco International agreed to register under the Securities Act notes having terms identical in all material respects to the 2024 Notes (the “2024 Exchange Notes”) and to make an offer to exchange the 2024 Exchange Notes for the 2024 Notes. Wesco Distribution launched the exchange offer on December 28, 2016 and the exchange offer expired on January 31, 2017. On June 2, 2021, Wesco Distribution exercised its right to redeem the entire $350 million aggregate principal amount of the 2024 Notes, and U.S. Bank, National Association, as trustee under the 2024 Indenture, issued a notice of redemption to registered holders of the 2024 Notes. On July 2, 2021, Wesco Distribution redeemed the $350 million aggregate principal amount of the 2024 Notes at a redemption price equal to 101.344% of the principal amount plus accrued interest to, but not including, July 2, 2021. The redemption of the 2024 Notes was funded with borrowings under the Company's Receivables Facility and Revolving Credit Facility. The Company recognized a loss on debt extinguishment totaling $6.9 million, which included $4.7 million for the premium paid to redeem the 2024 Notes and $2.2 million for the write-off of unamortized debt issuance costs. The loss was recorded as a component of interest expense in the Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2021. 5.50% Senior Notes due 2023 6.00% Senior Notes due 2025 On April 30, 2020, in connection with the Merger, Wesco Distribution commenced offers to purchase for cash (each, a “Wesco Tender Offer” and, together the “Wesco Tender Offers”) any and all of Anixter Inc.’s outstanding (i) 5.50% Senior Notes due 2023 (the “Anixter 2023 Senior Notes”), $350.0 million aggregate principal amount, issued under the Indenture, dated as of August 18, 2015 (the “Anixter 2023 Indenture”), by and among Anixter Inc., Anixter and Wells Fargo Bank, National Association, as trustee, and (ii) 6.00% Senior Notes due 2025 (the “Anixter 2025 Senior Notes” and, together with the Anixter 2023 Senior Notes, the "Anixter Senior Notes"), $250.0 million aggregate principal amount, issued under the Indenture, dated as of November 13, 2018 (the “Anixter 2025 Indenture” and, together with the Anixter 2023 Indenture, the “Anixter Indentures”) by and among Anixter Inc., Anixter and Wells Fargo Bank, National Association, as trustee. Concurrent with the Wesco Tender Offers, Anixter Inc. commenced consent solicitations to amend the definition of "Change of Control" under the applicable Indenture to exclude the Merger and related transactions and expressly permit a merger between Anixter Inc. and Anixter (the “Anixter Consent Solicitations”). On June 23, 2020 (the "Expiration Date"), following the completion of the Merger, the Wesco Tender Offers and Anixter Consent Solicitations expired and settled. Pursuant to the terms of the Offer to Purchase and Consent Solicitation Statement, dated April 30, 2020, holders of the Anixter Senior Notes that validly tendered and did not validly withdraw prior to such date, received total tender offer consideration of $1,012.50 per $1,000 principal amount of Anixter Senior Notes, which amount, in each case, included an early tender payment of $50.00 per $1,000 principal amount of Anixter Senior Notes. Holders who validly delivered their consents at or prior to the Expiration Date received a consent fee of $2.50 per $1,000 principal amount of Anixter Senior Notes. As of December 31, 2021, $58.6 million and $4.2 million aggregate principal amount of the Anixter 2023 Senior Notes and Anixter 2025 Senior Notes, respectively, were outstanding. 7.125% Senior Notes due 2025 7.250% Senior Notes due 2028 On June 12, 2020, Wesco Distribution issued $1,500 million aggregate principal amount of 7.125% Senior Notes due 2025 (the “2025 Notes”) and $1,325 million aggregate principal amount of 7.250% Senior Notes due 2028 (the “2028 Notes” and, together with the 2025 Notes, the “Notes”). The 2025 Notes were issued at a price of 100.000% of the aggregate principal amount. The 2028 Notes were issued at a price of 99.244% of the aggregate principal amount. Wesco incurred costs related to the issuance of the 2025 Notes and 2028 Notes totaling $33.1 million and $29.3 million, respectively, which were recorded as a reduction to the carrying value of the debt and are being amortized over the respective lives of the notes. The Notes were issued pursuant to, and are governed by, an indenture (the “Notes Indenture”), dated as of June 12, 2020, between the Company, Wesco Distribution and U.S. Bank National Association, as trustee (the “Trustee”). The Notes and related guarantees were issued in a private transaction exempt from the Securities Act and have not been, and will not be, registered under the Securities Act and may not be offered or sold in the U.S. absent registration or an applicable exemption from, or in a transaction not subject to the registration requirements of the Securities Act and other applicable securities laws. The Company used the net proceeds from the issuance of the Notes, together with borrowings under its Revolving Credit Facility and Receivables Facility and existing cash on hand, to finance the Merger and the other transactions contemplated by the Merger Agreement. The use of proceeds included (i) paying the cash portion of the Merger consideration to stockholders of Anixter, (ii) refinancing certain existing indebtedness of Anixter contemplated by the Merger Agreement, including financing the satisfaction and discharge, defeasance, redemption or other repayment in full of the 5.125% Senior Notes due 2021 of Anixter Inc., a wholly owned subsidiary of Anixter, and financing payments in connection with the Anixter Consent Solicitations and Wesco Tender Offers, as described above, (iii) refinancing other indebtedness of the Company, and (iv) paying fees, costs and expenses in connection with the foregoing. The Notes are unsecured and unsubordinated obligations of Wesco Distribution and are guaranteed on an unsecured, unsubordinated basis by the Company and Anixter Inc. The 2025 Notes accrue interest at a rate of 7.125% per annum, payable semi-annually in arrears on June 15 and December 15 of each year. The 2025 Notes will mature on June 15, 2025. The 2028 Notes accrue interest at a rate of 7.250% per annum, payable semi-annually in arrears on June 15 and December 15 of each year. The 2028 Notes will mature on June 15, 2028. Wesco Distribution may redeem all or a part of the 2025 Notes at any time prior to June 15, 2022 by paying a “make-whole” premium plus accrued and unpaid interest, if any, to but excluding the redemption date. In addition, at any time prior to June 15, 2022, Wesco Distribution may redeem up to 35% of the 2025 Notes with the net cash proceeds from certain equity offerings. At any time between June 15, 2022 and June 14, 2023, Wesco Distribution may redeem all or a part of the 2025 Notes at a redemption price equal to 103.563% of the principal amount. Between June 15, 2023 and June 14, 2024, Wesco Distribution may redeem all or a part of the 2025 Notes at a redemption price equal to 101.781% of the principal amount. On and after June 15, 2024, Wesco Distribution may redeem all or a part of the 2025 Notes at a redemption price equal to 100% of the principal amount. Wesco Distribution may redeem all or a part of the 2028 Notes at any time prior to June 15, 2023 by paying a “make-whole” premium plus accrued and unpaid interest, if any, to but excluding the redemption date. In addition, at any time prior to June 15, 2023, Wesco Distribution may redeem up to 35% of the 2028 Notes with the net cash proceeds from certain equity offerings. At any time between June 15, 2023 and June 14, 2024, Wesco Distribution may redeem all or a part of the 2028 Notes at a redemption price equal to 103.625% of the principal amount. Between June 15, 2024 and June 14, 2025, Wesco Distribution may redeem all or a part of the 2028 Notes at a redemption price equal to 102.417% of the principal amount. Between June 15, 2025 and June 14, 2026, Wesco Distribution may redeem all or a part of the 2028 Notes at a redemption price equal to 101.208% of the principal amount. On and after June 15, 2026, Wesco Distribution may redeem all or a part of the 2028 Notes at a redemption price equal to 100% of the principal amount. The Notes Indenture contains certain covenants that, among other things, limit (i) the Company’s and its subsidiaries’ ability to pay dividends on or repurchase the Company’s capital stock, incur liens on assets, engage in certain sale and leaseback transactions or sell certain assets, and (ii) the Company’s and any guarantor’s ability to sell all or substantially all of its assets to, or merge or consolidate with or into, other persons, in the case of each of the foregoing, subject to certain qualifications and exceptions, including the termination of certain of these covenants upon the Notes receiving investment grade credit ratings. The Notes Indenture contains certain events of default, including, among other things, failure to make required payments, failure to comply with certain agreements or covenants, failure to pay or acceleration of certain other indebtedness, certain events of bankruptcy and insolvency, and failure to pay certain judgments. An event of default under the Notes Indenture will allow either the Trustee or the holders of at least 25% in aggregate principal amount of the applicable series of the then-outstanding Notes to accelerate, or in certain cases, will automatically cause the acceleration of the amounts due under the applicable series of Notes. As of December 31, 2021, $1,500.0 million and $1,325.0 million aggregate principal amount of the 2025 Notes and 2028 Notes, respectively, were outstanding. Debt Issuance Costs Wesco capitalizes certain costs associated with the issuance of debt and such costs are amortized over the term of the respective debt instrument on a straight-line basis. Debt issuance costs are presented in the Consolidated Balance Sheets as a direct reduction to the carrying amount of the related debt liability. Upon prepayment of debt, the Company accelerates the recognition of an appropriate amount of the costs as refinancing or extinguishment of debt. As of December 31, 2021 and 2020, unamortized debt issuance costs of $62.5 million and $78.9 million were recorded in the Consolidated Balance Sheets, respectively. Covenant Compliance Wesco’s credit agreements contain various restrictive covenants that, among other things, impose limitations on: (i) dividend payments or certain other restricted payments or investments; (ii) the incurrence of additional indebtedness and guarantees; (iii) creation of liens; (iv) mergers, consolidation or sales of substantially all of Wesco’s assets; (v) certain transactions among affiliates; (vi) payments by certain subsidiaries to Wesco, and (vii) capital expenditures. In addition, the Revolving Credit Facility and the Receivables Facility require Wesco to meet certain fixed charge coverage tests depending on availability or liquidity, respectively. Wesco was in compliance with all financial covenants contained in its debt agreements as of December 31, 2021. The following table sets forth the aggregate principal repayment requirements for all indebtedness for the next five years and thereafter, as of December 31, 2021: (In thousands) 2022 $ 9,528 2023 64,831 2024 1,272,914 2025 2,105,486 2026 2,010 Thereafter 1,325,916 Total payments on debt $ 4,780,685 Debt discount (8,088) Total debt $ 4,772,597

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
CAPITAL STOCK	Preferred Stock There are 20 million shares of preferred stock authorized at a par value of $0.01 per share; there are no shares issued or outstanding. The Board of Directors has the authority, without further action by the stockholders, to issue all authorized preferred shares in one or more series and to fix the number of shares, designations, voting powers, preferences, optional and other special rights and the restrictions or qualifications thereof. The rights, preferences, privileges and powers of each series of preferred stock may differ with respect to dividend rates, liquidation values, voting rights, conversion rights, redemption provisions and other matters. Series A Preferred Stock The Company's Board of Directors authorized 25,000 shares of fixed-rate reset cumulative perpetual preferred stock, Series A, with a liquidation preference of $25,000 per whole preferred share and a par value of $0.01 per share (the "Series A Preferred Stock"). Depositary shares, each representing a 1/1,000th interest in a share of Series A Preferred Stock, are registered under the Securities Act of 1933, as amended. In connection with the Merger, as described in Note 6, "Acquisitions and Disposals", the Company issued 21,611,534 depositary shares, representing an interest in approximately 21,612 shares of Series A Preferred Stock. Holders of shares of the Series A Preferred Stock are entitled to receive, when, as and if declared by the Company's Board of Directors, cumulative cash dividends at an initial rate of 10.625% per annum of the $25,000 liquidation preference per share. On June 22, 2025, and every five-year period thereafter, the dividend rate on the Series A Preferred Stock resets and will be equal to the Five-year U.S. Treasury Rate plus a spread of 10.325%. Holders of the Series A Preferred Stock are not entitled to convert or exchange their shares of Series A Preferred stock into shares of any of Wesco’s other classes or series of stock or into any other security of Wesco (other than upon a change of control involving the issuance of additional shares of common stock or other change of control transaction, in each case, approved by holders of common stock). The Series A Preferred Stock has no stated maturity and will not be subject to any sinking fund, retirement fund or purchase fund or any other obligation of Wesco to redeem, repurchase or retire the Series A Preferred Stock. Holders of the Series A Preferred Stock will have limited voting rights, including the right to elect two directors to the Board of Directors of the Company in the event dividends on the Series A Preferred Stock remain unpaid for the equivalent of six or more full quarterly dividend periods. Common Stock There are 210 million shares of common stock and 20 million shares of Class B common stock authorized at a par value of $0.01 per share. The Class B common stock is identical to the common stock, except for voting and conversion rights. The holders of Class B common stock have no voting rights. With certain exceptions, Class B common stock may be converted, at the option of the holder, into the same number of shares of common stock. The terms of the Revolving Credit Facility, as well as the indentures governing the 2025 Notes and 2028 Notes, place certain limits on the Company's ability to declare or pay dividends and repurchase common stock. The share repurchases in 2019, as described in Note 13, "Earnings Per Share", were made within the limits of Wesco's various credit agreements. At December 31, 2021 and 2020, no dividends had been declared and, therefore, no retained earnings were reserved for dividend payments. Treasury Stock Common stock purchased for treasury is recorded at cost. At the date of subsequent reissue, the treasury stock account is reduced by the cost of such stock, with cost determined on a weighted-average basis.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	12. INCOME TAXES The following table sets forth the components of income before income taxes by jurisdiction: Year Ended December 31, 2021 2020 2019 (In thousands) United States $ 396,769 $ 26,031 $ 198,566 Foreign 185,143 96,811 83,495 Income before income taxes $ 581,912 $ 122,842 $ 282,061 The following table sets forth the components of the provision for income taxes: Year Ended December 31, 2021 2020 2019 (In thousands) Current income taxes: Federal $ 107,919 $ 25,605 $ 31,695 State 30,206 11,322 8,616 Foreign 55,670 19,414 6,347 Total current income taxes 193,795 56,341 46,658 Deferred income taxes: Federal (62,302) (17,913) 6,774 State (12,327) (7,264) 1,846 Foreign (3,656) (8,361) 4,585 Total deferred income taxes (78,285) (33,538) 13,205 Provision for income taxes $ 115,510 $ 22,803 $ 59,863 The following table sets forth the reconciliation between the federal statutory income tax rate and the effective tax rate: Year Ended December 31, 2021 2020 2019 Federal statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal income tax benefit 2.0 1.4 3.1 Deemed repatriation of undistributed foreign earnings — — (1.3) Tax effect of intercompany financing (3.2) (13.4) (5.5) Unrecognized tax benefits 2.5 2.1 (0.4) Nondeductible expenses 0.6 5.7 0.7 Change in valuation allowance (2.8) 1.8 0.6 Other (0.2) — 3.0 Effective tax rate 19.9 % 18.6 % 21.2 % The undistributed earnings of the Company's foreign subsidiaries amounted to approximately $1,851.6 million at December 31, 2021. Most of these earnings have been taxed in the U.S. under either the one-time transition tax or the GILTI tax regime imposed by the TCJA. Future distributions of previously taxed earnings by the Company's foreign subsidiaries should, therefore, result in minimal U.S. taxation. Wesco has elected to pay the transition tax in installments over eight years. As of December 31, 2021, the Company's liability for the transition tax was $60.7 million, which is recorded as components of other current and noncurrent liabilities in the Consolidated Balance Sheet. The Company continues to assert that the remaining undistributed earnings of its foreign subsidiaries are indefinitely reinvested. The distribution of earnings by Wesco's foreign subsidiaries in the form of dividends, or otherwise, may be subject to additional taxation. The Company estimates that additional taxes of approximately $82.2 million would be payable upon the remittance of all previously undistributed foreign earnings as of December 31, 2021, based upon the laws in effect on that date. The Company believes that it is able to maintain sufficient liquidity for its domestic operations and commitments without repatriating cash from Wesco's foreign subsidiaries. The following table sets forth deferred tax assets and liabilities: As of December 31, 2021 2020 (In thousands) Assets Liabilities Assets Liabilities Accounts receivable $ 18,612 $ — $ 17,560 $ — Inventories 13,302 — 14,793 — Depreciation of property, buildings and equipment — 45,397 — 60,687 Operating leases 142,964 141,686 134,377 136,477 Amortization of intangible assets — 549,536 — 540,520 Employee benefits 36,410 — 53,040 — Stock-based compensation 12,281 — 14,061 — Prepaid royalty payments 34,866 — — — Disallowed business interest expense (1) 11,163 — 2,755 — Tax loss carryforwards 39,876 — 36,923 — Foreign tax credit carryforwards 51,632 — 55,637 — Other (1) 26,666 8,137 24,888 6,286 Deferred income taxes before valuation allowance 387,772 744,756 354,034 743,970 Valuation allowance (46,269) — (60,629) — Total deferred income taxes $ 341,503 $ 744,756 $ 293,405 $ 743,970 (1) The deferred income tax asset of $2.8 million related to disallowed business interest expense as of December 31, 2020 was previously reported as a component of Other. This amount has been reclassified to conform to the current period's presentation. Wesco had deferred tax assets of $35.5 million and $34.5 million as of December 31, 2021 and 2020, respectively, related to foreign net operating loss carryforwards. These net operating loss carryforwards expire beginning in 2022 through 2041, while some may be carried forward indefinitely. The Company has determined that certain foreign net operating loss carryforwards will not be realized before they expire. Accordingly, the Company has recorded a valuation allowance of $22.1 million and $22.3 million against deferred tax assets related to certain foreign net operating loss carryforwards at December 31, 2021 and 2020, respectively. Additionally, these foreign jurisdictions had deferred tax assets of $6.9 million and $8.2 million as of December 31, 2021 and 2020, respectively, related to other future deductible temporary differences. The Company has recorded a full valuation allowance against these amounts as of December 31, 2021 and 2020, respectively. As of December 31, 2021 and 2020, Wesco had deferred tax assets of $4.4 million and $2.4 million, respectively, related to state net operating loss carryforwards. These carryforwards expire beginning in 2024 through 2040, while some may be carried forward indefinitely. The deferred tax assets related to disallowed business interest expense as of December 31, 2021 includes $4.7 million and $6.4 million for Federal and state income tax purposes, respectively. The carryforward period for disallowed business interest expense is indefinite. As of December 31, 2021 and 2020, Wesco had deferred tax assets of $51.6 million and $55.6 million, respectively, related to foreign tax credit carryforwards. The foreign tax credit carryforwards expire beginning in 2027 through 2031. The Company has determined that certain foreign tax credit carryforwards will not be realized before they expire. Accordingly, the Company has recorded a valuation allowance of $17.3 million and $30.1 million against these deferred tax assets at December 31, 2021 and 2020, respectively. Wesco’s ability to realize its deferred tax assets related to foreign tax credit carryforwards may be impacted by U.S. tax legislation, our ability to generate sufficient foreign source taxable income, and tax planning strategies that the Company may implement. The impact of these items, if any, on Wesco's assessment of the realizability of these deferred tax assets will be recorded as a discrete item in the period in which the Company's assessment changes. The Company is under examination by tax authorities in various jurisdictions and remains subject to examination until the applicable statutes of limitation expire. The statutes of limitation for the material jurisdictions in which the Company files income tax returns remain open as follows: United States — Federal 2017 and forward United States — Material States 2017 and forward Canada 2012 and forward UK 2016 and forward Australia 2017 and forward The following table sets forth the reconciliation of gross unrecognized tax benefits: As of December 31, 2021 2020 2019 (In thousands) Beginning balance January 1 $ 68,075 $ 54 $ 1,293 Additions for current year tax positions 39,841 14,009 — Additions for prior year tax positions 8,422 — — Additions for acquired tax positions — 68,048 — Reductions for prior year tax positions (3,853) (43) — Settlements (118) — (1,290) Lapse in statute of limitations (3,837) (15,886) — Foreign currency exchange rate changes (1,239) 1,893 51 Ending balance December 31 $ 107,291 $ 68,075 $ 54 The total amount of unrecognized tax benefits were $107.3 million and $68.1 million as of December 31, 2021 and 2020, respectively. The amount of unrecognized tax benefits that would affect the effective tax rate if recognized in the consolidated financial statements for the years ended December 31, 2021, 2020 and 2019 were $36.1 million, $29.1 million, and $0.1 million, respectively. Within the next twelve months, the amount of unrecognized tax benefits is expected to decrease by $14.3 million due to the expiration of statutes of limitation. Such change would result in a $3.2 million reduction in income tax expense. The Company classifies interest related to unrecognized tax benefits as a component of interest expense, net in the Consolidated Statement of Income and Comprehensive Income. The Company recognized interest expense on unrecognized tax benefits of $0.9 million and $0.3 million for the years ended December 31, 2021 and 2020, respectively. In 2019, the Company recognized interest income on unrecognized tax benefits of $0.8 million. As of December 31, 2021 and 2020, Wesco had a liability of $6.4 million and $5.5 million, respectively, for interest expense related to unrecognized tax benefits. The Company classifies penalties related to unrecognized tax benefits as part of income tax expense. For the year ended December 31, 2021, penalties recorded in income tax expense were $3.4 million. Penalties recorded in income tax expense for 2020 and 2019 were immaterial. As of December 31, 2021 and 2020, Wesco had a liability of $4.9 million and $1.5 million, respectively, for penalties related to unrecognized tax benefits. On October 22, 2021, one of the Company's Mexican affiliates received a tax assessment from the Mexican tax authorities related to its 2012 income tax return in the amount of approximately $26.0 million. The Company believes the assessment is without merit and has appealed it. The Company expects any potential liability remaining after availing itself of available administrative and judicial appeals to be immaterial to its consolidated financial statements and, accordingly, has not recorded a reserve.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
EARNINGS PER SHARE	Basic earnings per share is computed by dividing net income attributable to common stockholders by the weighted-average number of common shares outstanding during the periods. Diluted earnings per share is computed by dividing net income attributable to common stockholders by the weighted-average common shares and common share equivalents outstanding during the periods. The dilutive effect of common share equivalents is considered in the diluted earnings per share computation using the treasury stock method, which includes consideration of equity awards. The following table sets forth the details of basic and diluted earnings per share: Year Ended December 31, 2021 2020 2019 (In thousands, except per share data) Net income attributable to WESCO International, Inc. $ 465,382 $ 100,560 $ 223,426 Less: Preferred stock dividends 57,408 30,139 — Net income attributable to common stockholders $ 407,974 $ 70,421 $ 223,426 Weighted-average common shares outstanding used in computing basic earnings per share 50,300 46,174 43,104 Common shares issuable upon exercise of dilutive equity awards 1,730 451 383 Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share 52,030 46,625 43,487 Earnings per share attributable to common stockholders Basic $ 8.11 $ 1.53 $ 5.18 Diluted $ 7.84 $ 1.51 $ 5.14 The computation of diluted earnings per share attributable to common stockholders excludes stock-based awards that would have an antidilutive effect on earnings per share. For the year ended December 31, 2021, there were no antidilutive stock-based awards, and for the years ended December 31, 2020 and 2019, there were approximately 1.8 million and 1.7 million antidilutive awards, respectively. In December 2017, the Company's Board of Directors (the "Board") authorized the repurchase of up to $300 million of the Company's common stock through December 31, 2020 (the "Repurchase Authorization"). In October 2018, the Board approved an increase to the Repurchase Authorization from $300 million to $400 million. The Company entered into certain accelerated stock repurchase agreements with a financial institution to repurchase shares of its common stock pursuant to the Repurchase Authorization. In exchange for up-front cash payments totaling $275.0 million, the Company repurchased 5,459,030 shares of common stock under the Repurchase Authorization, of which 3,455,584 shares were received during the year ended December 31, 2019. The Company did not repurchase, nor did it receive, any of its common stock during the years ended December 31, 2021 and 2020.

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2021
Postemployment Benefits [Abstract]
Retirement Benefits	Defined Contribution Plans Wesco Distribution sponsors a defined contribution retirement savings plan for the majority of its U.S. employees (the "WESCO Distribution, Inc. Retirement Savings Plan"). The Company matches contributions made by employees at an amount equal to 50% of participants' total monthly contributions up to 6% of eligible compensation. Contributions are made in cash and employees have the option to transfer balances allocated to their accounts into any of the available investment options. The Company may also make, subject to the Board of Directors' approval, a discretionary contribution to the WESCO Distribution, Inc. Retirement Savings Plan if certain predetermined profit levels are attained. Discretionary employer contribution charges of $13.1 million were incurred for the year ended December 31, 2021. There were no discretionary contributions for the years ended December 31, 2020 and 2019. Anixter Inc. sponsors a defined contribution plan covering all of its non-union U.S. employees (the "Anixter Inc. Employee Savings Plan"). The employer match for the Anixter Inc. Employee Savings Plan is equal to 50% of a participant's contribution up to 5% of the participant's compensation. Anixter Inc. will also make an annual contribution to the Anixter Inc. Employee Savings Plan on behalf of each active participant who is hired or rehired on or after July 1, 2015, or is not participating in the Anixter Inc. Pension Plan. The amount of the employer annual contribution is equal to either 2% or 2.5% of the participant’s compensation, as determined by the participant’s years of service. This contribution is in lieu of being eligible for the Anixter Inc. Pension Plan. Certain of Anixter Inc.'s foreign subsidiaries also have defined contribution plans. Contributions to these plans are based upon various levels of employee participation and legal requirements. Effective January 1, 2022, the Anixter Inc. Employee Savings Plan will be merged with and into the WESCO Distribution, Inc. Retirement Savings Plan (the "U.S. Defined Contribution Plan Merger"). On December 31, 2021, participant account balances were transferred from the Anixter Inc. Employee Savings Plan to the WESCO Distribution, Inc. Retirement Savings Plan. In connection with the U.S. Defined Contribution Plan Merger, the WESCO Distribution, Inc. Retirement Savings plan will be amended to change the employer matching contribution at an amount equal to 100% of a participant’s eligible elective deferrals up to 3% of the participant’s eligible compensation and 50% of the next 4% of eligible compensation, and to eliminate the discretionary employer contributions. WESCO Distribution Canada LP, a wholly-owned subsidiary of the Company, sponsors a defined contribution plan covering the current full-time employees of WESCO Distribution Canada LP and part-time employees meeting certain requirements for continuous service, earnings and minimum hours of employment (the "Wesco Canadian Defined Contribution Plan"). The Company makes contributions in amounts ranging from 3% to 5% of participants' eligible compensation based on years of continuous service. For employees having completed between 20 and 25 or more years of service as of January 1, 2015, the Company's contribution ranges from 5% to 7% of the respective participants' eligible compensation. Anixter Canada Inc. sponsors a defined contribution plan for certain Canadian employees (the “Anixter Canadian Defined Contribution Plan”), which provides for core employer contributions in amounts ranging from 3% to 4% of participants' eligible compensation based on years of continuous service, plus a matching contribution equal to 25% of a participant’s elective contributions up to 6% of eligible compensation (for a maximum total employer contribution equal to 5.5%). Effective January 1, 2022, the Anixter Canadian Defined Contribution Plan will be merged with and into an amended Wesco Canadian Defined Contribution Plan. The amended Wesco Canadian Defined Contribution Plan will provide a core employer contribution of 3% of a participant’s eligible compensation, plus a matching contribution equal to 50% of a participant’s elective contributions up to 4% of eligible compensation (for a maximum total employer contribution equal to 5%). The amended Wesco Canadian Defined Contribution Plan will also require employees of EECOL Electric Corp. hired on or after January 1, 2022 to join this Canadian defined contribution plan, and will permit enrollment for those not participating in the defined benefit plan described below. Wesco incurred charges of $54.7 million, $18.3 million, and $22.9 million for the years ended December 31, 2021, 2020 and 2019, respectively, for all defined contribution plans. Deferred Compensation Plans Wesco Distribution sponsors a non-qualified deferred compensation plan (the "Wesco Deferred Compensation Plan") that permits select employees to make pre-tax deferrals of salary and bonus. Employees have the option to transfer balances allocated to their accounts in the Wesco Deferred Compensation Plan into any of the available investment options. The Wesco Deferred Compensation Plan is an unfunded plan. As of December 31, 2021, the Company's obligation under the Wesco Deferred Compensation Plan was $20.9 million, which was included in other noncurrent liabilities in the Consolidated Balance Sheet. As of December 31, 2020, the Company's obligation under the Wesco Deferred Compensation Plan was $27.4 million, of which $10.1 million was included in other current liabilities and $17.3 million was in other noncurrent liabilities in the Consolidated Balance Sheet. Anixter Inc. sponsored a non-qualified deferred compensation plan (the "Anixter Deferred Compensation Plan") that permitted select employees to make pre-tax deferrals of salary and bonus. Interest was accrued monthly on the deferred compensation balances based on the average ten-year Treasury note rate for the previous three months times a factor of 1.4, and the rate was further adjusted if certain financial goals were achieved. In the fourth quarter of 2020, the Company terminated the Anixter Deferred Compensation Plan. Accordingly, a deferred compensation liability of $45.1 million was classified in other current liabilities in the Consolidated Balance Sheet at December 31, 2020. In the second quarter of 2021, the Company settled the liability for the Anixter Deferred Compensation Plan by making lump sum payments of $42.8 million directly to participants. The Company held assets in a Rabbi Trust arrangement to provide for the liability associated with the Anixter Deferred Compensation Plan. The assets were invested in marketable securities. As of December 31, 2020, the assets held in this arrangement were $39.6 million and were recorded in other current assets in the Consolidated Balance Sheet. In the second quarter of 2021, the Company liquidated this investment arrangement for approximately $39.7 million and used its proceeds plus available cash to fund the settlement of the Anixter Deferred Compensation Plan described above. Defined Benefit Plans 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. 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. The Domestic Plans are funded as required by the Employee Retirement Income Security Act of 1974 ("ERISA") and the Internal Revenue Service. The Foreign Plans are funded as required by applicable foreign laws. In the fourth quarter of 2020, the Company terminated both the Anixter Inc. Executive Benefit Plan and the Anixter SERP. Accordingly, pension liabilities totaling $18.1 million associated with the Anixter Inc. Executive Benefit Plan and the Anixter SERP were classified as current in the Consolidated Balance Sheet at December 31, 2020. During the year ended December 31, 2021, the Company settled its liabilities for the Anixter Inc. Executive Benefit Plan and Anixter SERP by making lump sum payments directly to participants totaling $17.9 million. During the fourth quarter of 2021, the Company adopted certain plan amendments to freeze the benefits provided under the Anixter Inc. Pension Plan effective December 31, 2021, to close participation in the EECOL Plan effective December 31, 2021, and to freeze the benefit accruals under the Pension Plan for Employees of Anixter Canada Inc., the EECOL Plan and the EECOL SERP, effective December 31, 2023. These amendments required the Company to remeasure the projected benefit obligations associated with these plans, resulting in a gain from curtailment totaling $36.6 million, which is recorded as a component of other non-operating income in the Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2021. The following table presents the changes in benefit obligations, plan assets and funded status for the defined benefit plans: Domestic Plans Foreign Plans Total (In thousands) 2021 2020 2021 2020 2021 2020 Change in Projected Benefit Obligation Beginning balance $ 332,484 $ — $ 486,855 $ 134,852 $ 819,339 $ 134,852 Impact of acquisition (1) — 317,893 — 301,206 — 619,099 Service cost 3,033 1,763 12,140 9,029 15,173 10,792 Interest cost 8,219 4,787 9,801 7,162 18,020 11,949 Participant contributions — — 846 728 846 728 Actuarial (gain) loss, including assumption changes (10,649) 12,911 (35,483) 14,044 (46,132) 26,955 Benefits paid from plan assets (8,988) (4,222) (11,343) (9,008) (20,331) (13,230) Benefits paid from Company assets (527) (547) (461) (448) (988) (995) Curtailment (3,900) (101) (32,680) — (36,580) (101) Plan amendment — — (104) (37) (104) (37) Settlement (17,889) — (219) (1,235) (18,108) (1,235) Foreign currency exchange rate changes — — (5,256) 30,562 (5,256) 30,562 Ending balance $ 301,783 $ 332,484 $ 424,096 $ 486,855 $ 725,879 $ 819,339 Change in Plan Assets at Fair Value Beginning balance $ 355,287 $ — $ 365,718 $ 103,385 $ 721,005 $ 103,385 Impact of acquisition (1) — 324,292 — 218,644 — 542,936 Actual return on plan assets 24,432 35,217 19,661 23,947 44,093 59,164 Participant contributions — — 846 728 846 728 Employer contributions 17,889 — 10,240 6,838 28,129 6,838 Benefits paid (8,988) (4,222) (11,343) (9,008) (20,331) (13,230) Settlement (17,889) — (218) (1,235) (18,107) (1,235) Foreign currency exchange rate changes — — (3,123) 22,419 (3,123) 22,419 Ending balance $ 370,731 $ 355,287 $ 381,781 $ 365,718 $ 752,512 $ 721,005 Funded Status $ 68,948 $ 22,803 $ (42,315) $ (121,137) $ 26,633 $ (98,334) Amounts Recognized in the Consolidated Balance Sheets Other assets $ 68,948 $ 40,921 $ 4,818 $ 179 $ 73,766 $ 41,100 Other current liabilities — (18,118) (437) (471) (437) (18,589) Other noncurrent liabilities — — (46,696) (120,845) (46,696) (120,845) Net amount recognized $ 68,948 $ 22,803 $ (42,315) $ (121,137) $ 26,633 $ (98,334) Weighted Average Assumptions Used to Determine Benefit Obligations Discount rate 2.9 % 2.6 % 2.4 % 2.0 % 2.6 % 2.2 % Rate of compensation increase — % 3.8 % 3.4 % 3.2 % 3.4 % 3.4 % (1) The Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020, as disclosed in Note 6, "Acquisitions and Disposals". For all defined benefit plans assumed as part of the merger with Anixter, the projected benefit obligation and fair value of plan assets were remeasured as of the acquisition date. The measurement date for all plans is December 31st. Accordingly, at the end of each fiscal year, the Company determines the discount rate to measure the plan liabilities at their present value. The discount rate reflects the current rate at which the pension liabilities could effectively be settled at the measurement date. This rate was estimated at the end of 2021 and 2020 using a yield curve based on corporate bond data, which the Company concluded was consistent with observable market conditions and industry standards for developing spot rate curves. At December 31, 2021 and 2020, the consolidated weighted-average discount rate of all plans was 2.6% and 2.2%, respectively, and these rates were used to measure the projected benefit obligation at the end of each respective year-end. The consolidated net funded status was $26.6 million at December 31, 2021, compared to a consolidated net unfunded status of $98.3 million at December 31, 2020. At December 31, 2021 and 2020, the Company's projected benefit obligation was $301.8 million and $332.5 million, respectively, for the Domestic Plans and $424.1 million and $486.9 million, respectively, for the Foreign Plans. The Company had 9 plans at December 31, 2021 and 13 plans at December 31, 2020 for which the projected benefit obligation was in excess of the fair value of plan assets. For these plans, the aggregate projected benefit obligation was $214.5 million and $504.8 million, respectively, and the aggregate fair value of plan assets was $167.4 million and $365.4 million, respectively. At December 31, 2021 and 2020, the Company' accumulated benefit obligation was $301.8 million and $328.2 million, respectively, for the Domestic Plans and $390.8 million and $417.6 million, respectively, for the Foreign Plans. The Company had 9 plans at December 31, 2021 and 13 plans at December 31, 2020 for which the accumulated benefit obligation was in excess of the fair value of plan assets. For these plans, the aggregate accumulated benefit obligation was $194.6 million and $435.6 million, respectively, and the aggregate fair value of plan assets was $167.4 million and $365.4 million, respectively. The following tables set forth the components of net periodic pension (benefit) cost for the Company's defined benefit plans: Domestic Plans (1) Foreign Plans (1) Total (In thousands) 2021 2020 2019 2021 2020 2019 2021 2020 2019 Components of Net Periodic Pension (Benefit) Cost Service cost $ 3,033 $ 1,763 $ — $ 12,140 $ 9,029 $ 4,602 $ 15,173 $ 10,792 $ 4,602 Interest cost 8,219 4,787 — 9,801 7,162 4,362 18,020 11,949 4,362 Expected return on plan assets (17,097) (8,395) — (17,834) (11,659) (5,695) (34,931) (20,054) (5,695) Recognized actuarial gain — — — 90 — (63) 90 — (63) Curtailment (3,900) — — (32,680) — — (36,580) — — Settlement 290 — — (59) (144) — 231 (144) — Net periodic pension (benefit) cost $ (9,455) $ (1,845) $ — $ (28,542) $ 4,388 $ 3,206 $ (37,997) $ 2,543 $ 3,206 (1) As described above, the Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020. The Company began recognizing the associated net periodic pension (benefit) cost as of the acquisition date. The service cost of $15.2 million, $10.8 million and $4.6 million for the years ended December 31, 2021, 2020 and 2019, respectively, is reported as a component of selling, general and administrative expenses. The other components of net periodic pension (benefit) cost totaling net benefits of $53.2 million, $8.2 million and $1.4 million for the years ended December 31, 2021, 2020 and 2019, respectively, are presented as components of other non-operating income ("other income, net"). The following weighted-average actuarial assumptions were used to determine net periodic pension (benefit) cost: Domestic Plans (1) Foreign Plans (1) Total 2021 2020 2019 2021 2020 2019 2021 2020 2019 Discount rate 2.6 % 2.9 % — % 2.0 % 2.2 % 4.0 % 2.3 % 2.5 % 4.0 % Expected return on plan assets 5.3 % 5.5 % — % 4.9 % 5.2 % 6.4 % 5.1 % 5.3 % 6.4 % Rate of compensation increase 3.8 % 3.8 % — % 3.2 % 3.4 % 3.8 % 3.4 % 3.5 % 3.8 % (1) As described above, the Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020. The Company began using the related assumptions as of the acquisition date. The expected long-term rate of return on plan assets reflects the average rate of earnings expected on the invested assets and future assets to be invested to provide for the benefits included in the projected benefit obligation. The Company uses historic plan asset returns combined with current market conditions to estimate the rate of return. The weighted-average expected long-term rate of return on plan assets used in the determination of net periodic pension cost for 2021 was 5.1%. As a result of the combined effect of valuation changes in both the equity and bond markets, the plan assets produced an actual gain of 6.0% in 2021. The difference between the expected return and actual return on plan assets is amortized into expense over the service lives of the plan participants. These amounts are reflected on the balance sheet through charges to accumulated other comprehensive loss, a component of stockholders’ equity. The following table sets forth the changes and the end of year components of accumulated other comprehensive (income) loss for the defined benefit plans: Year Ended December 31, (In thousands) 2021 2020 Changes to Balance: Beginning balance, before tax effect $ (3,062) $ 8,890 Prior service credit arising in current year (100) (37) Net actuarial gain arising in current year (93,064) (12,154) Recognized actuarial gain (90) — Curtailment 36,580 (101) Settlement (231) 144 Foreign currency exchange rate changes 1,179 196 Ending balance, before tax effect $ (58,788) $ (3,062) As of December 31, (In thousands) 2021 2020 Components of Balance: Prior service credit $ (137) $ (37) Net actuarial gain (58,651) (3,025) Ending balance, before tax effect (58,788) (3,062) Tax effect 13,605 562 Ending balance, after tax effect $ (45,183) $ (2,500) The following benefit payments, which reflect expected future service, are expected to be paid as follows: (In thousands) Domestic Plans Foreign Plans Total 2022 $ 11,215 $ 9,430 $ 20,645 2023 11,743 9,654 21,397 2024 12,385 10,294 22,679 2025 12,890 11,065 23,955 2026 13,508 11,525 25,033 2027 to 2031 73,410 84,171 157,581 The Company expects to contribute approximately $10.8 million to its Foreign Plans in 2022. The Company does not expect to make a contribution to its domestic qualified pension plan in 2022 due to its overfunded status. The assets of the various defined benefit plans are held in separate independent trusts and managed by independent third party advisors. The investment objective for the defined benefit plans is to ensure an adequate level of assets is available to fund the benefits owed to employees and their beneficiaries when they become payable. In meeting this objective, the Company seeks to achieve a level of absolute investment return consistent with a prudent level of portfolio risk. The Company's risk preference is to refrain from exposing the plans to higher volatility in pursuit of potential higher returns. The asset mixes and the asset allocation guidelines for the Domestic Plans and Foreign Plans are summarized as follows: Domestic Plans Allocation Guidelines December 31, 2021 Min Target Max Equities 10.8 % 5 % 10 % 15 % Debt securities: Domestic treasuries 36.1 — 34 — Corporate bonds 25.7 — 40 — Other 7.6 3 7 13 Total debt securities 69.4 81 Property/real estate 19.0 3 8 13 Other 0.8 — 1 — 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2021 Min Target Max Equities 39.2 % 25 % 39 % 48 % Debt securities: Corporate bonds 4.5 — — 37 Other 43.5 26 48 65 Total debt securities 48.0 48 Property/real estate 4.4 2 5 8 Insurance products 4.9 5 5 5 Other 3.5 3 3 13 100.0 % 100 % Domestic Plans Allocation Guidelines December 31, 2020 Min Target Max Equities 38.6 % 30 % 37 % 45 % Debt securities: Domestic treasuries 22.2 — 24 40 Corporate bonds 6.7 — 8 40 Other 15.6 9 14 19 Total debt securities 44.5 46 Property/real estate 14.8 9 16 23 Other 2.1 — 1 5 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2020 Min Target Max Equities 38.1 % 25 % 41 % 48 % Debt securities: Corporate bonds 5.9 % 1 1 37 Other 40.6 26 44 65 Total debt securities 46.5 45 Property/real estate 4.8 2 6 8 Insurance products 5.4 5 5 5 Other 5.2 3 3 12 100.0 % 100 % The plans' pension committees meet regularly to assess investment performance relative to asset allocation guidelines. The Company periodically rebalances its asset portfolios to be in line with its allocation guidelines. For 2021, the investment policy guidelines of the Domestic Plans were as follows: • Each asset class is managed by one or more active and passive investment managers • Each asset class may be invested in a commingled fund, mutual fund, or separately managed account • Investment in Exchange Traded Funds ("ETFs") is permissible • Each manager is expected to be "fully invested" with minimal cash holdings • Derivative instruments such as futures, swaps and options may be used on a limited basis; for funds that employ derivatives, the loss of invested capital to the Trust should be limited to the amount invested in the fund • The equity portfolio is diversified by sector and geography • The real assets portfolio is invested in Real Estate Investment Trusts ("REITs") and private real estate • The fixed income is invested in U.S. Treasuries, investment grade corporate debt (denominated in U.S. dollars), and other credit investments including below investment grade rated bonds and loans, securitized credit, and emerging market debt The investment policies for the Foreign Plans are the responsibility of the various trustees. Generally, the investment policy guidelines are as follows: • Make sure that the obligations to the beneficiaries of the plan can be met • Maintain funds at a level to meet the minimum funding requirements • The investment managers are expected to provide a return, within certain tracking tolerances, close to that of the relevant market’s indices The following tables set forth the fair value of assets by asset category for the Domestic Plans and Foreign Plans: December 31, 2021 (In thousands) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 40,102 $ 40,102 Debt securities: Domestic treasuries — — — 133,672 133,672 Corporate bonds — — — 95,198 95,198 Other — — — 28,246 28,246 Property/real estate — — — 70,648 70,648 Other 2,865 — — — 2,865 Total investments in Domestic Plans $ 2,865 $ — $ — $ 367,866 $ 370,731 Foreign Plans Equities $ — $ — $ — $ 149,707 $ 149,707 Debt securities: Corporate bonds — — — 17,328 17,328 Other — — — 165,863 165,863 Property/real estate — — — 16,632 16,632 Insurance products — 18,781 — — 18,781 Other 1,248 — — 12,222 13,470 Total investments in Foreign Plans $ 1,248 $ 18,781 $ — $ 361,752 $ 381,781 Total Equities $ — $ — $ — $ 189,809 $ 189,809 Debt securities: Domestic treasuries — — — 133,672 133,672 Corporate bonds — — — 112,526 112,526 Other — — — 194,109 194,109 Property/real estate — — — 87,280 87,280 Insurance products — 18,781 — — 18,781 Other 4,113 — — 12,222 16,335 Total investments $ 4,113 $ 18,781 $ — $ 729,618 $ 752,512 (1) Investments measured at fair value using the NAV per share practical expedient have not been classified in the fair value hierarchy. The amounts presented in the tables above are intended to reconcile the fair value hierarchy to the total fair value of plan assets. December 31, 2020 (In thousands) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 137,098 $ 137,098 Debt securities: Domestic treasuries — — — 78,808 78,808 Corporate bonds — — — 23,824 23,824 Other — — — 55,547 55,547 Property/real estate — — — 52,708 52,708 Other 7,302 — — — 7,302 Total investments in Domestic Plans $ 7,302 $ — $ — $ 347,985 $ 355,287 Foreign Plans Equities $ — $ — $ — $ 139,537 139,537 Debt securities: Corporate bonds — — — 21,677 21,677 Other — — — 148,469 148,469 Property/real estate — — — 17,365 17,365 Insurance products — 19,611 — — 19,611 Other 747 — — 18,312 19,059 Total investments in Foreign Plans $ 747 $ 19,611 $ — $ 345,360 $ 365,718 Total Equities $ — $ — $ — $ 276,635 $ 276,635 Debt securities: Domestic treasuries — — — 78,808 78,808 Corporate bonds — — — 45,501 45,501 Other — — — 204,016 204,016 Property/real estate — — — 70,073 70,073 Insurance products — 19,611 — — 19,611 Other 8,049 — — 18,312 26,361 Total investments $ 8,049 $ 19,611 $ — $ 693,345 $ 721,005 (1) Investments measured at fair value using the NAV per share practical expedient have not been classified in the fair value hierarchy. The amounts presented in the tables above are intended to reconcile the fair value hierarchy to the total fair value of plan assets. The assets of the Domestic Plans and Foreign Plans are measured at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities are classified in the fair value hierarchy based on the lowest level of any input that is significant to the measurement of fair value. Investments for which fair value is measured using the net asset value (NAV) per share practical expedient are not classified in the fair value hierarchy. The majority of pension assets are comprised of common/collective/pool funds (i.e., mutual funds). These funds are valued at the net asset value of shares held in the underlying funds. The fair value methods described above may not be indicative of net realizable value or reflective of future fair values. Additionally, while the Company believes the valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. Other Benefits As permitted by the Merger Agreement, Anixter granted restricted stock units prior to June 22, 2020 in the ordinary course of business to its employees and directors. These awards, for which vesting did not accelerate solely as a result of the Merger, were converted into cash-only settled Wesco phantom stock units, which vest ratably over a 3-year period. As of December 31, 2021 and 2020, the estimated fair value of these awards was $22.7 million and $22.8 million, respectively. As of December 31, 2021, the Company's liability for these awards was $17.3 million, of which $10.9 million was included in accrued payroll and benefit costs and $6.4 million was a component of other noncurrent liabilities in the Consolidated Balance Sheet. As of December 31, 2020, the Company's liability for these awards was $11.7 million, of which $6.5 million was included in accrued payroll and benefit costs and $5.2 million was a component of other noncurrent liabilities in the Consolidated Balance Sheet. The Company recognized compensation expense associated with these awards of $13.6 million and $9.2 million for the years ended December 31, 2021 and 2020, respectively, which is reported as a component of selling, general and administrative expenses.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Wesco sponsors a stock-based compensation plan. On May 27, 2021, the Company's stockholders approved the WESCO International, Inc. 2021 Omnibus Incentive Plan (the “2021 Plan”). The 2021 Plan is administered by the Compensation Committee of the Company's Board of Directors. The 2021 Plan was designed to be the successor plan to all prior stock-based compensation plans. Accordingly, no new awards may be granted under the Company’s 1999 Long-Term Incentive Plan, as amended and restated (the “1999 Plan”) or any other prior plan. Awards outstanding under any such prior plans will remain in full force and effect under such plans according to their respective terms. To the extent that any such award is forfeited, terminates, expires or lapses without being exercised, or is settled for cash, the shares subject to such award not delivered will again be available for awards under the 2021 Plan. The maximum number of shares of the Company’s common stock that may be granted pursuant to awards under the 2021 Plan is 2,150,000, less any shares issued under the 1999 Plan between March 31, 2021 and May 27, 2021. If any award granted under the 2021 Plan is forfeited, terminates, expires or lapses instead of being exercised, or is settled for cash, the shares subject to such award will again be available for grant under the 2021 Plan. Shares delivered by participants or withheld by the Company to pay all or a portion of the exercise price or withholding taxes with respect to stock option or stock appreciation right awards will not again be available for issuance. Shares delivered by participants or withheld by the Company to satisfy applicable tax withholding obligations with respect to restricted shares or restricted stock units will again be available for grant under the 2021 Plan. As of December 31, 2021, 2,138,865 shares of common stock were reserved under the 2021 Plan for future equity award grants. Stock-based employee compensation awards outstanding under Wesco's plans are comprised of stock-settled stock appreciation rights, restricted stock units and performance-based awards. Compensation cost for all stock-based awards is measured at fair value on the date of grant and compensation cost is recognized, net of estimated forfeitures, over the service period for awards expected to vest. The fair value of stock-settled stock appreciation rights is determined using the Black-Scholes model. The fair value of restricted stock units and performance-based awards with performance conditions is determined by the grant-date closing price of Wesco’s common stock. The forfeiture assumption is based on Wesco’s historical employee behavior that is reviewed on an annual basis. No dividends are assumed. For stock-settled stock appreciation rights that are exercised and for restricted stock units and performance-based awards that vest, shares are issued out of Wesco's outstanding common stock. Stock-settled stock appreciation rights vest ratably over a three-year period and terminate on the tenth anniversary of the grant date unless terminated sooner under certain conditions. Restricted stock unit awards granted in February 2020 and prior vest based on a minimum time period of three years. The special award described below vests in tranches. Restricted stock units awarded in 2021 vest ratably over a three-year period on each of the first, second and third anniversaries of the grant date. Vesting of performance-based awards is based on a three-year performance period, and the number of shares earned, if any, depends on the attainment of certain performance levels. Outstanding awards would vest upon the consummation of a change in control transaction and performance-based awards would vest at the target level. On July 2, 2020, a special award of restricted stock units was granted to certain officers of the Company. These awards vest in tranches of 30% on each of the first and second anniversaries of the grant date and 40% on the third anniversary of the grant date, subject, in each case, to continued employment through the applicable anniversary date. Performance-based awards granted in 2021, 2020 and 2019 are based on two equally-weighted performance measures: the three-year average growth rate of Wesco's net income attributable to common stockholders and the three-year cumulative return on net assets. Wesco recognized $30.8 million, $19.3 million and $19.1 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the years ended December 31, 2021, 2020 and 2019, respectively. As of December 31, 2021, there was $45.1 million of total unrecognized compensation expense related to non-vested stock-based compensation arrangements for all awards previously made of which approximately $26.4 million is expected to be recognized in 2022, $17.0 million in 2023 and $1.7 million in 2024. The aggregate intrinsic value of awards exercised during the years ended December 31, 2021, 2020, and 2019 was $69.7 million, $8.8 million, and $10.7 million, respectively. The gross deferred income tax benefit associated with the exercise of stock-based awards totaled $16.8 million, $2.0 million, and $2.5 million in 2021, 2020, and 2019, respectively. The following table sets forth a summary of stock-settled stock appreciation rights and related information for the periods presented: Year Ended December 31, 2021 2020 2019 Awards Weighted-Average Weighted-Average Aggregate Awards Weighted-Average Awards Weighted-Average Beginning of year 2,161,556 $ 60.48 2,337,049 $ 59.72 2,351,633 $ 59.26 Granted 139,592 77.05 262,091 48.32 213,618 54.63 Exercised (916,906) 60.70 (391,339) 47.11 (113,099) 35.01 Canceled (13,854) 54.42 (46,245) 65.93 (115,103) 65.27 End of year 1,370,388 62.09 6.1 $ 95,246 2,161,556 60.48 2,337,049 59.72 Exercisable at end of year 1,001,708 $ 62.79 5.3 $ 68,920 1,630,891 $ 62.72 1,723,370 $ 59.00 The following table sets forth the weighted-average assumptions used to estimate the fair value of stock-settled stock appreciation rights granted during the periods presented: Year Ended December 31, 2021 2020 2019 Stock-settled stock appreciation rights granted 139,592 262,091 213,618 Risk free interest rate 0.8% 1.4% 2.5% Expected life (in years) 7 5 5 Expected volatility 41% 30% 29% The risk-free interest rate is based on the U.S. Treasury Daily Yield Curve rate as of the grant date. The expected life is based on historical exercise experience and the expected volatility is based on the volatility of the Company's daily stock prices over the expected life preceding the grant date. The weighted-average fair value per stock-settled stock appreciation right granted was $33.19, $13.86 and $16.36 for the years ended December 31, 2021, 2020 and 2019, respectively. The following table sets forth a summary of time-based restricted stock units and related information for the periods presented: Year Ended December 31, 2021 2020 2019 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 921,495 $ 43.15 363,729 $ 60.00 327,798 $ 57.87 Granted 314,480 77.81 656,717 37.44 192,106 54.13 Vested (232,152) 44.10 (83,253) 69.17 (136,777) 46.52 Forfeited (29,661) 63.86 (15,698) 56.79 (19,398) 59.62 Unvested at end of year 974,162 $ 53.48 921,495 $ 43.15 363,729 $ 60.00 The following table sets forth a summary of performance-based awards and related information for the periods presented: Year Ended December 31, 2021 2020 2019 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 305,269 $ 52.61 195,305 $ 60.24 138,896 $ 59.33 Granted 122,812 76.76 158,756 49.56 126,874 54.64 Vested (22,371) 62.80 (25,909) 78.04 (25,696) 42.44 Forfeited (24,891) 61.26 (22,883) 69.39 (44,769) 52.11 Unvested at end of year 380,819 $ 59.23 305,269 $ 52.61 195,305 $ 60.24 Vesting of the 380,819 shares of performance-based awards in the table above is dependent upon the achievement of certain performance targets, including half that are dependent upon the three-year average growth rate of Wesco's net income attributable to common stockholders and the other half that are based upon the three-year cumulative return on net assets. These awards are accounted for as awards with performance conditions; compensation cost is recognized over the performance period based upon Wesco's determination of whether it is probable that the performance targets will be achieved.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	From time to time, a number of lawsuits and claims have been or may be asserted against the Company relating to the conduct of its business, including litigation relating to commercial, product and employment matters (including wage and hour). The outcome of any litigation cannot be predicted with certainty, and some lawsuits may be determined adversely to Wesco. However, management does not believe that the ultimate outcome of any such pending matters is likely to have a material adverse effect on Wesco's financial condition or liquidity, although the resolution in any fiscal period of one or more of these matters may have a material adverse effect on Wesco's results of operations for that period. As of December 31, 2021, the Company had $50.1 million in outstanding letters of credit and guarantees.

BUSINESS SEGMENTS

BUSINESS SEGMENTS	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
SEGMENTS AND RELATED INFORMATION	17. BUSINESS SEGMENTS The Company has operating segments that are organized around three strategic business units consisting of EES, CSS and UBS. These operating segments are equivalent to the Company's reportable segments. The Company's chief operating decision maker evaluates the performance of its operating segments based primarily on net sales, income from operations, adjusted EBITDA, adjusted EBITDA margin percentage, and total assets. The following is a description of each of the Company's reportable segments and their business activities. Electrical & Electronic Solutions The EES segment, with over 6,400 employees supporting customers in over 50 countries, supplies a broad range of products and solutions primarily to the construction, industrial and original equipment manufacturer ("OEM") markets. The product portfolio in this business includes a broad range of electrical equipment and supplies, automation and connected devices (the "Internet of Things" or "IoT"), security, lighting, wire and cable, safety, and maintenance, repair and operating ("MRO") products from industry-leading manufacturing partners. The EES service portfolio includes contractor solutions to improve project execution, direct and indirect manufacturing supply chain optimization programs, lighting and renewables advisory services, and digital and automation solutions to improve safety and productivity. Communications & Security Solutions The CSS segment, with over 3,300 employees supporting customers in over 50 countries, is a global leader in the network infrastructure and security markets. CSS sells products directly to end-users or through various channels including data communications contractors, security, network, professional audio/visual and systems integrators. In addition to the core network infrastructure and security portfolio, CSS has a broad offering of safety and energy management solutions. CSS products are often combined with supply chain services to increase efficiency and productivity, including installation enhancement, project deployment, advisory, and IoT and digital services. Utility & Broadband Solutions The UBS segment, with over 2,400 employees supporting customers primarily in the U.S. and Canada, provides products and services to investor-owned utilities, public power companies, including municipalities, as well as global service providers, wireless providers, broadband operators and the contractors that service these customers. The UBS segment also includes Wesco's integrated supply business, which provides products and services to large industrial and commercial end-users to support their MRO spend. The products sold into the utility and broadband markets include wire and cable, transformers, transmission and distribution hardware, switches, protective devices, connectors, lighting, conduit, fiber and copper cable, connectivity products, pole line hardware, racks, cabinets, safety and MRO products, and point-to-point wireless devices. The UBS segment also offers a complete set of service solutions to improve customer supply chain efficiencies. Corporate Corporate primarily incurs costs related to treasury, tax, information technology, legal and other centralized functions. The Company also has various corporate assets which are reported in corporate. Segment assets may not include jointly used assets, but segment results include depreciation expense or other allocations related to those assets. Interest expense and other non-operating items are either not allocated to the segments or reviewed on a segment basis. Corporate expenses and assets not directly identifiable with a reportable segment are reported in the tables below to reconcile the reportable segments to the consolidated financial statements. The following table sets forth financial information by reportable segment for the periods presented: (In thousands) Year Ended December 31, 2021 EES CSS UBS Corporate Total Net sales $ 7,621,263 $ 5,715,238 $ 4,881,011 $ — $ 18,217,512 Income from operations 542,059 395,343 412,740 (548,269) 801,873 Adjusted EBITDA 604,461 480,820 428,367 (337,965) 1,175,683 Adjusted EBITDA Margin % 7.9 % 8.4 % 8.8 % 6.5 % Supplemental information: Depreciation and amortization $ 55,998 $ 82,870 $ 22,447 $ 37,239 $ 198,554 Capital expenditures 4,469 3,197 5,207 41,873 54,746 Year Ended December 31, 2020 (In thousands) EES CSS UBS Corporate Total Net sales $ 5,479,760 $ 3,323,264 $ 3,522,971 $ — $ 12,325,995 Income from operations 260,207 217,163 231,702 (362,034) 347,038 Adjusted EBITDA 308,327 280,656 265,593 (194,259) 660,317 Adjusted EBITDA Margin % 5.6 % 8.4 % 7.5 % 5.4 % Supplemental information: Depreciation and amortization $ 35,811 $ 37,765 $ 22,380 $ 25,644 $ 121,600 Capital expenditures 7,081 1,495 12,834 35,261 56,671 Year Ended December 31, 2019 (In thousands) EES CSS UBS Corporate Total Net sales $ 4,860,541 $ 909,496 $ 2,588,880 $ — $ 8,358,917 Income from operations 261,788 43,835 184,931 (144,337) 346,217 Adjusted EBITDA 291,473 51,067 198,745 (110,769) 430,516 Adjusted EBITDA Margin % 6.0 % 5.6 % 7.7 % 5.2 % Supplemental information: Depreciation and amortization $ 28,569 $ 7,155 $ 13,583 $ 12,800 $ 62,107 Capital expenditures 20,405 3,093 6,460 14,109 44,067 The following table sets forth total assets by reportable segment for the periods presented: As of December 31, 2021 (In thousands) EES CSS UBS Corporate (1) Total Total assets $ 4,098,335 $ 4,601,132 $ 3,266,231 $ 652,001 $ 12,617,699 As of December 31, 2020 (In thousands) EES CSS UBS Corporate (1) Total Total assets $ 3,726,855 $ 4,275,611 $ 2,947,406 $ 930,342 $ 11,880,214 (1) Total assets for Corporate primarily consist of cash and cash equivalents, deferred income taxes, fixed assets and right-of-use assets associated with operating leases. The following table sets forth tangible long-lived assets, which include property, buildings and equipment, and operating lease assets, by geographic area: As of December 31, 2021 2020 (In thousands) United States $ 698,942 $ 693,807 Canada 141,380 146,620 Other International (1) 69,553 93,435 Total $ 909,875 $ 933,862 (1) No individual other international country's tangible long-lived assets are material. The following tables reconcile net income attributable to common stockholders to adjusted EBITDA and adjusted EBITDA margin % by segment, which are non-GAAP financial measures, for the periods presented: Year Ended December 31, 2021 (In thousands) EES CSS UBS Corporate Total Net income attributable to common stockholders $ 543,633 $ 394,031 $ 412,698 $ (942,388) $ 407,974 Net income attributable to noncontrolling interests 298 — — 722 1,020 Preferred stock dividends — — — 57,408 57,408 Provision for income taxes — — — 115,510 115,510 Interest expense, net — — — 268,073 268,073 Depreciation and amortization 55,998 82,870 22,447 37,239 198,554 Other (income) expense, net (1) (1,872) 1,312 42 (47,594) (48,112) Stock-based compensation expense (2) 6,404 2,607 2,107 14,581 25,699 Merger-related and integration costs — — — 158,484 158,484 Net gain on Canadian divestitures — — (8,927) — (8,927) Adjusted EBITDA $ 604,461 $ 480,820 $ 428,367 $ (337,965) $ 1,175,683 Adjusted EBITDA margin % 7.9 % 8.4 % 8.8 % 6.5 % (1) Corporate other non-operating income in the calculation of adjusted EBITDA for the year ended December 31, 2021 includes a $36.6 million curtailment gain resulting from the remeasurement of the Company's pension obligations in the U.S. and Canada due to amending certain terms of such defined benefit plans. (2) Stock-based compensation expense in the calculation of adjusted EBITDA for the year ended December 31, 2021 excludes $5.1 million as such amount is included in merger-related and integration costs. Year Ended December 31, 2020 (In thousands) EES CSS UBS Corporate Total Net income attributable to common stockholders $ 262,829 $ 217,211 $ 231,678 $ (641,297) $ 70,421 Net loss attributable to noncontrolling interests (842) — — 321 (521) Preferred stock dividends — — — 30,139 30,139 Provision for income taxes — — — 22,803 22,803 Interest expense, net — — — 226,591 226,591 Depreciation and amortization 35,811 37,765 22,380 25,644 121,600 Other (income) expense, net (1,780) (48) 24 (591) (2,395) Stock-based compensation expense (3)(4) 4,080 1,403 1,336 9,895 16,714 Merger-related and integration costs — — — 132,236 132,236 Merger-related fair value adjustments 15,411 22,000 6,282 — 43,693 Out-of-period adjustment (3) 12,634 2,325 3,893 — 18,852 Gain on sale of asset (19,816) — — — (19,816) Adjusted EBITDA $ 308,327 $ 280,656 $ 265,593 $ (194,259) $ 660,317 Adjusted EBITDA margin % 5.6 % 8.4 % 7.5 % 5.4 % (3) Stock-based compensation and the out-of-period adjustment by reportable segment for the year ended December 31, 2020, as previously reported in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020, have been reallocated to conform to the current period's presentation. (4) Stock-based compensation expense in the calculation of adjusted EBITDA for the year ended December 31, 2020 excludes $2.6 million as such amount is included in merger-related and integration costs. Year Ended December 31, 2019 (In thousands) EES CSS UBS Corporate Total Net income attributable to common stockholders $ 264,570 $ 43,835 $ 184,931 $ (269,910) $ 223,426 Net loss attributable to noncontrolling interests (1,228) — — — (1,228) Provision for income taxes — — — 59,863 59,863 Interest expense, net — — — 65,710 65,710 Depreciation and amortization 28,569 7,155 13,583 12,800 62,107 Other income, net (1,554) — — — (1,554) Stock-based compensation expense 1,116 77 231 17,638 19,062 Merger-related costs — — — 3,130 3,130 Adjusted EBITDA $ 291,473 $ 51,067 $ 198,745 $ (110,769) $ 430,516 Adjusted EBITDA margin % 6.0 % 5.6 % 7.7 % 5.2 % Note: Adjusted EBITDA and Adjusted EBITDA margin % are non-GAAP financial measures that provide indicators of the Company's performance and its ability to meet debt service requirements. Adjusted EBITDA is defined as earnings before interest, taxes, depreciation and amortization before foreign exchange and other non-operating expenses (income), non-cash stock-based compensation, costs and fair value adjustments associated with the merger with Anixter, an out-of-period adjustment related to inventory cost absorption accounting, and net gains on the divestiture of Wesco's legacy utility and data communications businesses in Canada and sale of an operating branch in the U.S. Adjusted EBITDA margin % is calculated by dividing Adjusted EBITDA by net sales.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II—Valuation and Qualifying Accounts Balance at Charged to Charged to Balance at of period earnings accounts (1) Deductions (2) end of period Allowance for expected credit losses (In thousands) Year Ended December 31, 2021 $ 23,909 $ 12,944 $ 13,669 $ (8,800) $ 41,722 Year Ended December 31, 2020 25,443 11,701 5,160 (18,395) 23,909 Year Ended December 31, 2019 24,468 7,006 52 (6,083) 25,443 (1) For the years ended December 31, 2021 and 2020, the amount charged to other accounts primarily relates to the acquisition of Anixter. (2) Includes a reduction in the allowance for expected credit losses due to the write-off of trade accounts receivable. Balance at Charged to Charged to Balance at of period earnings accounts (1) Deductions (2) end of period Allowance for deferred tax assets (In thousands) Year Ended December 31, 2021 $ 60,629 $ 1,115 $ 1,791 $ (17,266) $ 46,269 Year Ended December 31, 2020 5,854 1,900 52,875 — 60,629 Year Ended December 31, 2019 4,072 1,745 37 — 5,854 (1) For the year ended December 31, 2020, the amount charged to other accounts includes $59.3 million that was recorded in connection with the acquisition of Anixter. (2) For the year ended December 31, 2021, deductions primarily include a decrease in the valuation allowance recorded against deferred tax assets related to foreign tax credit carryforwards.

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Basis of Presentation The consolidated financial statements include the accounts of Wesco International and all of its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Out-of-Period Adjustment In the fourth quarter of 2020, management determined that the Company’s inventories were overstated by $60.3 million because of a misstatement in inventory cost absorption accounting, which occurred over multiple periods and also impacted inventories acquired in business combinations during those periods. Accordingly, the Consolidated Balance Sheet at December 31, 2020 reflects a reduction to inventories of $60.3 million, an increase to goodwill of $33.9 million and a decrease to deferred income tax liabilities of $12.0 million. The resulting effect of the out-of-period adjustment on the Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2020 was a $18.9 million increase to cost of goods sold, which decreased net income for the year by $14.4 million. Management concluded that this misstatement was not material to the prior year or the financial statements of any previously filed annual or interim periods. Change in Estimates During the second quarter of 2021, the Company established a new corporate brand strategy that will result in migrating certain legacy sub-brands to a master brand architecture. The Company accounts for the trademarks associated with these sub-brands as intangible assets. As of December 31, 2020, $39.1 million of the trademarks impacted by the master brand strategy had indefinite lives and $9.5 million had remaining estimated useful lives ranging from 3 to 8 years. As disclosed further below, the Company continually evaluates whether events or circumstances have occurred that would require a change to the estimated useful lives of indefinite-lived and definite lived intangible assets. When such a change is warranted, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. Accordingly, during the second quarter of 2021, the Company changed the estimated useful lives of the trademarks affected by the new corporate brand strategy to coincide with the expected period of time to migrate such sub-brands to the master brand architecture. The Company assigned remaining estimated useful lives to these trademarks, including those that previously had indefinite lives, ranging from less than one year to 5 years. The Company assessed these intangible assets for impairment prior to amortizing them over their revised estimated remaining useful lives. No impairment losses were identified as a result of these tests. For the year ended December 31, 2021, the Company recognized $32.0 million of amortization expense resulting from these changes in estimated useful lives. Reclassifications The Consolidated Statements of Cash Flows for the years ended December 31, 2020 and 2019, respectively, include certain reclassifications to previously reported amounts to conform to the current period's presentation. Such reclassifications had no impact on the totals of operating, investing and financing cash flow activities for those years. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles in the United States of America requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates are based on management’s best knowledge of current events and actions Wesco may undertake in the future, actual results may ultimately differ from the estimates. Revenue Recognition Wesco’s revenue arrangements generally consist of single performance obligations to transfer a promised good or service, or a combination of goods and services. Revenue is measured as the amount of consideration Wesco expects to receive in exchange for transferring goods or providing services. Revenue is recognized when control has transferred to the customer, which is generally when the product has shipped from a Wesco facility or directly from a supplier. However, transfer may occur at a later date depending on the agreed upon terms, such as delivery at the customer's designated location, or based on consignment terms. For products that ship directly from suppliers to customers, Wesco acts as the principal in the transaction and recognizes revenue on a gross basis. When providing services, sales are recognized over time as control transfers to the customer, which occurs as services are rendered. Wesco generally satisfies its performance obligations within a year or less. Wesco generally does not have significant financing terms associated with its contractual arrangements; payments are normally received within 60 days. There are generally no significant costs associated with obtaining customer contracts. Wesco typically passes through warranties offered by manufacturers or suppliers to its customers. Sales taxes (and value added taxes in foreign jurisdictions) collected from customers and remitted to governmental authorities are excluded from net sales. Supplier Volume Rebates Wesco receives volume rebates from certain suppliers based on contractual arrangements with such suppliers. Volume rebates are included within other receivables in the Consolidated Balance Sheets, and represent the estimated amounts due to Wesco based on forecasted purchases and the rebate provisions of the various supplier contracts. The corresponding rebate income is recorded as a reduction to cost of goods sold. Receivables under the supplier rebate program were $219.1 million at December 31, 2021 and $136.7 million at December 31, 2020. The supplier volume rebate income as a percentage of net sales was 1.4% in 2021, 1.1% in 2020 and 1.2% in 2019. Cash Equivalents Cash equivalents are defined as highly liquid investments with original maturities of 90 days or less when purchased. Allowance for Expected Credit Losses Wesco recognizes expected credit losses resulting from the inability of its customers to make required payments through an allowance account that is measured each reporting period. Wesco estimates credit losses over the life of its trade accounts receivable using a combination of historical loss data, current credit conditions, specific customer circumstances, and reasonable and supportable forecasts of future economic conditions. The allowance for expected credit losses was $41.7 million at December 31, 2021 and $23.9 million at December 31, 2020. The total amount recorded as selling, general and administrative expense related to credit losses was $12.9 million, $10.1 million and $7.0 million for 2021, 2020 and 2019, respectively. Inventories Inventories primarily consist of merchandise purchased for resale and are stated at the lower of cost and net realizable value. Cost is determined principally under the average cost method. Wesco reduces the carrying value of its inventories at the earlier of identifying an item that is considered to be obsolete or in excess of supply relative to demand, or no movement in a prescribed number of months. Reserves for excess and obsolete inventories were $50.3 million and $28.7 million at December 31, 2021 and 2020, respectively. The total expense related to excess and obsolete inventories, which is included in cost of goods sold, was $37.1 million, $15.7 million and $10.0 million for 2021, 2020 and 2019, respectively. Property, Buildings and Equipment Property, buildings and equipment are recorded at cost. Depreciation expense is determined using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized over either their respective lease terms or their estimated lives, whichever is shorter. Estimated useful lives range from five to forty years for buildings and leasehold improvements and two to ten years for furniture, fixtures and equipment. Costs incurred during the application development stage of internally developed software are capitalized and are reported at the lower of unamortized cost or net realizable value. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Capitalized costs include external direct costs of materials and services consumed in developing internal-use computer software, payroll and payroll-related costs for employees who are directly associated with and who devote time to the internal-use computer software project, as well as interest costs. Internal-use computer software is amortized using the straight-line method over its estimated useful life, typically three to seven years. Expenditures for new facilities and improvements that extend the useful life of an asset are capitalized. Ordinary repairs and maintenance are expensed as incurred. When property is retired or otherwise disposed, the cost and the related accumulated depreciation are removed from the accounts and any resulting gains or losses are recorded and reported as selling, general and administrative expenses. Of Wesco’s $379.0 million net book value of property, buildings and equipment as of December 31, 2021, $133.6 million consists of land, buildings and leasehold improvements that are geographically dispersed among Wesco’s 800 branches, warehouses and sales offices, mitigating the risk of impairment. Wesco assesses its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of any such assets may not be fully recoverable. Changes in circumstances include technological advances, changes in the business model, capital structure, economic conditions or operating performance. The evaluation is based upon, among other things, utilization, serviceability and assumptions developed by management, which are categorized as Level 3 of the fair value hierarchy, related to the estimated future undiscounted cash flows that these assets are expected to generate. When the sum of the undiscounted cash flows is less than the carrying value of the asset (asset group), an impairment loss is recognized to the extent that carrying value exceeds fair value. Management applies its best judgment when performing these evaluations. Leases The determination of whether an arrangement is, or contains, a lease is performed at the inception of the arrangement. Classification and initial measurement of the right-of-use asset and lease liability are determined at the lease commencement date. The Company elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of 12 months or less are not recorded on the balance sheet. Operating lease expense is recognized on a straight-line basis over the lease term. Operating lease assets and liabilities are recognized at the commencement date based on the present value of the future minimum lease payments. Certain leases contain rent escalation clauses that are either fixed or adjusted periodically for inflation or market rates and such clauses are factored into the Company's determination of lease payments. Wesco also has variable lease payments that do not depend on a rate or index, primarily for items such as common area maintenance and real estate taxes, which are recorded as variable expense when incurred. The operating lease asset includes advance payments and excludes incentives and initial direct costs incurred. The Company's arrangements include certain non-lease components such as common area and other maintenance for leased real estate, as well as mileage, fuel and maintenance costs related to leased automobiles and trucks. Wesco accounts for these non-lease components separately from the associated lease components. The Company does not guarantee any residual value in its lease agreements, and there are no material restrictions or covenants imposed by lease arrangements. Real estate leases typically include one or more options to extend the lease, or terminate early. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term. For most of Wesco’s leases, the discount rate implicit in the lease is not readily determinable. Accordingly, the Company uses its incremental borrowing rate based on the information available at the lease commencement date to discount lease payments to the present value. Goodwill and Indefinite-Lived Intangible Assets Goodwill and indefinite-lived intangible assets are tested for impairment annually during the fourth quarter, or more frequently if triggering events occur, indicating that their carrying value may not be recoverable. Wesco tests for goodwill impairment on a reporting unit level. The Company first assesses qualitative factors, including macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, other relevant events such as changes in key personnel, changes in the composition or carrying amount of the net assets of a reporting unit, and changes in in share price, to determine whether it is more likely than not that the fair value of Wesco's reporting units are less than their carrying values. If the qualitative assessment indicates that the fair values of the Company's reporting units may not exceed their respective carrying values, then Wesco performs a quantitative test for impairment by comparing the fair value of each reporting unit to its carrying value. The Company determines the fair values of its reporting units using a discounted cash flow analysis and consideration of market multiples. The discounted cash flow analysis uses certain assumptions, including expected operating margins supported by a combination of historical results, current forecasts, market data and recent economic events, which are categorized within Level 3 of the fair value hierarchy. The Company uses a discount rate that reflects market participants' cost of capital. Wesco evaluates the recoverability of indefinite-lived intangible assets using the relief-from-royalty method based on projected financial information. Significant inputs used in the relief-from-royalty method include projected revenues, discount rates, royalty rates, and applicable income tax rates. At December 31, 2021 and 2020, goodwill and indefinite-lived trademarks totaled $4.0 billion. The determination of fair value involves significant management judgment, particularly as it relates to the underlying assumptions and factors around expected operating margins and discount rate. Management applies its best judgment when assessing the reasonableness of financial projections. Fair values are sensitive to changes in underlying assumptions and factors. As a result, there can be no assurance that the estimates and assumptions made for purposes of the annual goodwill and indefinite-lived intangible impairment tests will prove to be an accurate prediction of future results. Definite Lived Intangible Assets Definite lived intangible assets are amortized over 1 to 20 years. Certain customer relationships are amortized using an accelerated method whereas all other definite lived intangible assets subject to amortization use a straight-line method. In either case, the amortization method reflects the pattern in which the economic benefits of the respective assets are consumed or otherwise used. Wesco continually evaluates whether events or circumstances have occurred that would indicate the remaining estimated useful lives of definite lived intangible assets require revision or that the remaining carrying value of such assets may not be recoverable. Insurance Programs Wesco uses commercial insurance for auto, workers’ compensation, casualty and health claims, and information technology as a risk-reduction strategy to minimize catastrophic losses. The Company’s strategy involves large deductible policies where Wesco must pay all costs up to the deductible amount. Wesco estimates the reserve for these programs based on historical incident rates and costs. The assumptions included in developing this accrual include the period of time between the incurrence and payment of a claim. The total liability related to insurance programs was $30.6 million and $27.9 million at December 31, 2021 and 2020, respectively. Income Taxes Wesco accounts for income taxes under the asset and liability method, which requires the recognition of deferred income taxes for events that have future tax consequences. Under this method, deferred income taxes are recognized (using enacted tax laws and rates) based on the future income tax effects of differences in the carrying amounts of assets and liabilities for financial reporting and tax purposes. The effect of a tax rate change on deferred tax assets and liabilities is recognized in income in the period of change. Wesco recognizes deferred tax assets at amounts that are expected to be realized. To make such determination, management evaluates all positive and negative evidence, including but not limited to, prior, current and future taxable income, tax planning strategies and future reversals of existing taxable temporary differences. A valuation allowance is recognized if it is “more-likely-than-not” that some or all of a deferred tax asset will not be realized. Wesco regularly assesses the realizability of deferred tax assets. Wesco accounts for uncertainty in income taxes using a "more-likely-than-not" recognition threshold. Due to the subjectivity inherent in the evaluation of uncertain tax positions, the tax benefit ultimately recognized may materially differ from the estimate recognized in the consolidated financial statements. Wesco recognizes interest and penalties related to uncertain tax benefits as part of interest expense and income tax expense, respectively. The Tax Cuts and Jobs Act of 2017 (the “TCJA”) imposed a one-time tax on the deemed repatriation of undistributed foreign earnings (the “transition tax”). Except for a portion of foreign earnings previously taxed in the U.S. that can effectively be distributed without further material U.S. or foreign taxation, the Company continues to assert that the undistributed earnings of its foreign subsidiaries are indefinitely reinvested. To the extent the earnings of the Company's foreign subsidiaries are distributed in the form of dividends, such earnings may be subject to additional taxes. The Company believes that it is able to maintain a sufficient level of liquidity for its domestic operations and commitments without incurring any material tax cost to repatriate cash held by its foreign subsidiaries. The provisions of the TCJA also introduced U.S. taxation on certain global intangible low-taxed income ("GILTI"). Wesco has elected to account for GILTI tax as a component of income tax expense. Foreign Currency The local currency is the functional currency for most of the Company's operations outside the U.S. Assets and liabilities of these operations are translated to U.S. dollars at the exchange rate in effect at the end of each period. Income statement accounts are translated at an exchange rate that approximates the average for the period. Translation adjustments arising from the use of differing exchange rates from period to period are included as a component of other comprehensive income (loss) within stockholders’ equity. Gains and losses from foreign currency transactions are included in net income for the period. Defined Benefit Pension Plan Liabilities and expenses for defined benefit pension plans are determined using actuarial methodologies and incorporate significant assumptions, including the interest rate used to discount the future estimated cash flows, the expected long-term rate of return on plan assets, and several assumptions relating to the employee workforce (salary increases, retirement age, and mortality). Unrealized gains and losses related to the Company's defined benefit pension obligations are recognized as a component of other comprehensive income (loss) within stockholders' equity. Gains or losses resulting from plan amendments, curtailments, and settlements are recognized as a component of other non-operating income and expenses ("other, net") in the period of the remeasurement. Fair Value of Financial Instruments The Company measures the fair value of assets and liabilities on a recurring and nonrecurring basis according to a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of the fair value hierarchy are as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that are accessible at the measurement date; Level 2 inputs include inputs other than Level 1 that are observable, either directly or indirectly, and Level 3 inputs are unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to measurements involving significant unobservable inputs (Level 3). The Company measures the fair values of goodwill, intangible assets and property, buildings and equipment on a nonrecurring basis if required by impairment tests applicable to these assets, as described above. Other, net Other non-operating income and expenses ("other, net") primarily includes the non-service cost components of net periodic pension cost (benefit) and foreign exchange gains and losses. Recently Adopted Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which removes certain exceptions to the general principles of Accounting Standards Codification ("ASC") Topic 740, Income Taxes , and simplifies other aspects of accounting for income taxes. The amendments in this ASU were effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption was permitted in any interim or annual period, with any adjustments reflected as of the beginning of the fiscal year of adoption. The Company adopted this ASU in the first quarter of 2021. The adoption of this guidance did not have a material impact on the consolidated financial statements and notes thereto presented herein. Recently Issued Accounting Pronouncements In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , which requires contract assets and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance with ASC Topic 606, Revenue from Contracts with Customers , as if the acquirer had originated the contracts. The amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Management is currently evaluating the impact that the adoption of this accounting standard will have on its consolidated financial statements and notes thereto. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting , which provides optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendments in this Update are effective for all entities as of March 12, 2020 through December 31, 2022. Management does not expect the replacement of London Interbank Offered Rate (LIBOR) and the related adoption of the optional guidance under this accounting standard to have a material impact on the Company's consolidated financial statements and notes thereto. Other pronouncements issued by the FASB or other authoritative accounting standards groups with future effective dates are either not applicable or are not expected to be significant to Wesco’s financial position, results of operations or cash flows.
Basis of Consolidation	Basis of Presentation The consolidated financial statements include the accounts of Wesco International and all of its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Error Correction	Out-of-Period Adjustment In the fourth quarter of 2020, management determined that the Company’s inventories were overstated by $60.3 million because of a misstatement in inventory cost absorption accounting, which occurred over multiple periods and also impacted inventories acquired in business combinations during those periods. Accordingly, the Consolidated Balance Sheet at December 31, 2020 reflects a reduction to inventories of $60.3 million, an increase to goodwill of $33.9 million and a decrease to deferred income tax liabilities of $12.0 million. The resulting effect of the out-of-period adjustment on the Consolidated Statement of Income and Comprehensive Income for the year ended December 31, 2020 was a $18.9 million increase to cost of goods sold, which decreased net income for the year by $14.4 million. Management concluded that this misstatement was not material to the prior year or the financial statements of any previously filed annual or interim periods.
Change in Accounting Estimate	Change in Estimates During the second quarter of 2021, the Company established a new corporate brand strategy that will result in migrating certain legacy sub-brands to a master brand architecture. The Company accounts for the trademarks associated with these sub-brands as intangible assets. As of December 31, 2020, $39.1 million of the trademarks impacted by the master brand strategy had indefinite lives and $9.5 million had remaining estimated useful lives ranging from 3 to 8 years. As disclosed further below, the Company continually evaluates whether events or circumstances have occurred that would require a change to the estimated useful lives of indefinite-lived and definite lived intangible assets. When such a change is warranted, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. Accordingly, during the second quarter of 2021, the Company changed the estimated useful lives of the trademarks affected by the new corporate brand strategy to coincide with the expected period of time to migrate such sub-brands to the master brand architecture. The Company assigned remaining estimated useful lives to these trademarks, including those that previously had indefinite lives, ranging from less than one year to 5 years. The Company assessed these intangible assets for impairment prior to amortizing them over their revised estimated remaining useful lives. No impairment losses were identified as a result of these tests. For the year ended December 31, 2021, the Company recognized $32.0 million of amortization expense resulting from these changes in estimated useful lives.
Reclassification, Policy [Policy Text Block]	Reclassifications The Consolidated Statements of Cash Flows for the years ended December 31, 2020 and 2019, respectively, include certain reclassifications to previously reported amounts to conform to the current period's presentation. Such reclassifications had no impact on the totals of operating, investing and financing cash flow activities for those years.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles in the United States of America requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates are based on management’s best knowledge of current events and actions Wesco may undertake in the future, actual results may ultimately differ from the estimates.
Revenue Recognition	Revenue Recognition Wesco’s revenue arrangements generally consist of single performance obligations to transfer a promised good or service, or a combination of goods and services. Revenue is measured as the amount of consideration Wesco expects to receive in exchange for transferring goods or providing services. Revenue is recognized when control has transferred to the customer, which is generally when the product has shipped from a Wesco facility or directly from a supplier. However, transfer may occur at a later date depending on the agreed upon terms, such as delivery at the customer's designated location, or based on consignment terms. For products that ship directly from suppliers to customers, Wesco acts as the principal in the transaction and recognizes revenue on a gross basis. When providing services, sales are recognized over time as control transfers to the customer, which occurs as services are rendered. Wesco generally satisfies its performance obligations within a year or less. Wesco generally does not have significant financing terms associated with its contractual arrangements; payments are normally received within 60 days. There are generally no significant costs associated with obtaining customer contracts. Wesco typically passes through warranties offered by manufacturers or suppliers to its customers. Sales taxes (and value added taxes in foreign jurisdictions) collected from customers and remitted to governmental authorities are excluded from net sales.
Cost of Goods and Service	Supplier Volume Rebates Wesco receives volume rebates from certain suppliers based on contractual arrangements with such suppliers. Volume rebates are included within other receivables in the Consolidated Balance Sheets, and represent the estimated amounts due to Wesco based on forecasted purchases and the rebate provisions of the various supplier contracts. The corresponding rebate income is recorded as a reduction to cost of goods sold. Receivables under the supplier rebate program were $219.1 million at December 31, 2021 and $136.7 million at December 31, 2020. The supplier volume rebate income as a percentage of net sales was 1.4% in 2021, 1.1% in 2020 and 1.2% in 2019.
Cash Equivalents	Cash Equivalents Cash equivalents are defined as highly liquid investments with original maturities of 90 days or less when purchased.
Allowance for Doubtful Accounts	Allowance for Expected Credit LossesWesco recognizes expected credit losses resulting from the inability of its customers to make required payments through an allowance account that is measured each reporting period. Wesco estimates credit losses over the life of its trade accounts receivable using a combination of historical loss data, current credit conditions, specific customer circumstances, and reasonable and supportable forecasts of future economic conditions. The allowance for expected credit losses was $41.7 million at December 31, 2021 and $23.9 million at December 31, 2020. The total amount recorded as selling, general and administrative expense related to credit losses was $12.9 million, $10.1 million and $7.0 million for 2021, 2020 and 2019, respectively.
Inventories	Inventories Inventories primarily consist of merchandise purchased for resale and are stated at the lower of cost and net realizable value. Cost is determined principally under the average cost method. Wesco reduces the carrying value of its inventories at the earlier of identifying an item that is considered to be obsolete or in excess of supply relative to demand, or no movement in a prescribed number of months. Reserves for excess and obsolete inventories were $50.3 million and $28.7 million at December 31, 2021 and 2020, respectively. The total expense related to excess and obsolete inventories, which is included in cost of goods sold, was $37.1 million, $15.7 million and $10.0 million for 2021, 2020 and 2019, respectively.
Property, Buildings and Equipment	Property, Buildings and Equipment Property, buildings and equipment are recorded at cost. Depreciation expense is determined using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized over either their respective lease terms or their estimated lives, whichever is shorter. Estimated useful lives range from five to forty years for buildings and leasehold improvements and two to ten years for furniture, fixtures and equipment. Costs incurred during the application development stage of internally developed software are capitalized and are reported at the lower of unamortized cost or net realizable value. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Capitalized costs include external direct costs of materials and services consumed in developing internal-use computer software, payroll and payroll-related costs for employees who are directly associated with and who devote time to the internal-use computer software project, as well as interest costs. Internal-use computer software is amortized using the straight-line method over its estimated useful life, typically three to seven years. Expenditures for new facilities and improvements that extend the useful life of an asset are capitalized. Ordinary repairs and maintenance are expensed as incurred. When property is retired or otherwise disposed, the cost and the related accumulated depreciation are removed from the accounts and any resulting gains or losses are recorded and reported as selling, general and administrative expenses. Of Wesco’s $379.0 million net book value of property, buildings and equipment as of December 31, 2021, $133.6 million consists of land, buildings and leasehold improvements that are geographically dispersed among Wesco’s 800 branches, warehouses and sales offices, mitigating the risk of impairment. Wesco assesses its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of any such assets may not be fully recoverable. Changes in circumstances include technological advances, changes in the business model, capital structure, economic conditions or operating performance. The evaluation is based upon, among other things, utilization, serviceability and assumptions developed by management, which are categorized as Level 3 of the fair value hierarchy, related to the estimated future undiscounted cash flows that these assets are expected to generate. When the sum of the undiscounted cash flows is less than the carrying value of the asset (asset group), an impairment loss is recognized to the extent that carrying value exceeds fair value. Management applies its best judgment when performing these evaluations.
Lessee, Leases	Leases The determination of whether an arrangement is, or contains, a lease is performed at the inception of the arrangement. Classification and initial measurement of the right-of-use asset and lease liability are determined at the lease commencement date. The Company elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of 12 months or less are not recorded on the balance sheet. Operating lease expense is recognized on a straight-line basis over the lease term. Operating lease assets and liabilities are recognized at the commencement date based on the present value of the future minimum lease payments. Certain leases contain rent escalation clauses that are either fixed or adjusted periodically for inflation or market rates and such clauses are factored into the Company's determination of lease payments. Wesco also has variable lease payments that do not depend on a rate or index, primarily for items such as common area maintenance and real estate taxes, which are recorded as variable expense when incurred. The operating lease asset includes advance payments and excludes incentives and initial direct costs incurred. The Company's arrangements include certain non-lease components such as common area and other maintenance for leased real estate, as well as mileage, fuel and maintenance costs related to leased automobiles and trucks. Wesco accounts for these non-lease components separately from the associated lease components. The Company does not guarantee any residual value in its lease agreements, and there are no material restrictions or covenants imposed by lease arrangements. Real estate leases typically include one or more options to extend the lease, or terminate early. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term. For most of Wesco’s leases, the discount rate implicit in the lease is not readily determinable. Accordingly, the Company uses its incremental borrowing rate based on the information available at the lease commencement date to discount lease payments to the present value.
Goodwill and Intangible Assets	Goodwill and Indefinite-Lived Intangible Assets Goodwill and indefinite-lived intangible assets are tested for impairment annually during the fourth quarter, or more frequently if triggering events occur, indicating that their carrying value may not be recoverable. Wesco tests for goodwill impairment on a reporting unit level. The Company first assesses qualitative factors, including macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, other relevant events such as changes in key personnel, changes in the composition or carrying amount of the net assets of a reporting unit, and changes in in share price, to determine whether it is more likely than not that the fair value of Wesco's reporting units are less than their carrying values. If the qualitative assessment indicates that the fair values of the Company's reporting units may not exceed their respective carrying values, then Wesco performs a quantitative test for impairment by comparing the fair value of each reporting unit to its carrying value. The Company determines the fair values of its reporting units using a discounted cash flow analysis and consideration of market multiples. The discounted cash flow analysis uses certain assumptions, including expected operating margins supported by a combination of historical results, current forecasts, market data and recent economic events, which are categorized within Level 3 of the fair value hierarchy. The Company uses a discount rate that reflects market participants' cost of capital. Wesco evaluates the recoverability of indefinite-lived intangible assets using the relief-from-royalty method based on projected financial information. Significant inputs used in the relief-from-royalty method include projected revenues, discount rates, royalty rates, and applicable income tax rates. At December 31, 2021 and 2020, goodwill and indefinite-lived trademarks totaled $4.0 billion.
Definite Lived Intangible Assets	Definite Lived Intangible Assets Definite lived intangible assets are amortized over 1 to 20 years. Certain customer relationships are amortized using an accelerated method whereas all other definite lived intangible assets subject to amortization use a straight-line method. In either case, the amortization method reflects the pattern in which the economic benefits of the respective assets are consumed or otherwise used. Wesco continually evaluates whether events or circumstances have occurred that would indicate the remaining estimated useful lives of definite lived intangible assets require revision or that the remaining carrying value of such assets may not be recoverable.
Insurance Programs	Insurance Programs Wesco uses commercial insurance for auto, workers’ compensation, casualty and health claims, and information technology as a risk-reduction strategy to minimize catastrophic losses. The Company’s strategy involves large deductible policies where Wesco must pay all costs up to the deductible amount. Wesco estimates the reserve for these programs based on historical incident rates and costs. The assumptions included in developing this accrual include the period of time between the incurrence and payment of a claim. The total liability related to insurance programs was $30.6 million and $27.9 million at December 31, 2021 and 2020, respectively.
Income Taxes	Income Taxes Wesco accounts for income taxes under the asset and liability method, which requires the recognition of deferred income taxes for events that have future tax consequences. Under this method, deferred income taxes are recognized (using enacted tax laws and rates) based on the future income tax effects of differences in the carrying amounts of assets and liabilities for financial reporting and tax purposes. The effect of a tax rate change on deferred tax assets and liabilities is recognized in income in the period of change. Wesco recognizes deferred tax assets at amounts that are expected to be realized. To make such determination, management evaluates all positive and negative evidence, including but not limited to, prior, current and future taxable income, tax planning strategies and future reversals of existing taxable temporary differences. A valuation allowance is recognized if it is “more-likely-than-not” that some or all of a deferred tax asset will not be realized. Wesco regularly assesses the realizability of deferred tax assets. Wesco accounts for uncertainty in income taxes using a "more-likely-than-not" recognition threshold. Due to the subjectivity inherent in the evaluation of uncertain tax positions, the tax benefit ultimately recognized may materially differ from the estimate recognized in the consolidated financial statements. Wesco recognizes interest and penalties related to uncertain tax benefits as part of interest expense and income tax expense, respectively. The Tax Cuts and Jobs Act of 2017 (the “TCJA”) imposed a one-time tax on the deemed repatriation of undistributed foreign earnings (the “transition tax”). Except for a portion of foreign earnings previously taxed in the U.S. that can effectively be distributed without further material U.S. or foreign taxation, the Company continues to assert that the undistributed earnings of its foreign subsidiaries are indefinitely reinvested. To the extent the earnings of the Company's foreign subsidiaries are distributed in the form of dividends, such earnings may be subject to additional taxes. The Company believes that it is able to maintain a sufficient level of liquidity for its domestic operations and commitments without incurring any material tax cost to repatriate cash held by its foreign subsidiaries. The provisions of the TCJA also introduced U.S. taxation on certain global intangible low-taxed income ("GILTI"). Wesco has elected to account for GILTI tax as a component of income tax expense.
Foreign Currency	Foreign Currency The local currency is the functional currency for most of the Company's operations outside the U.S. Assets and liabilities of these operations are translated to U.S. dollars at the exchange rate in effect at the end of each period. Income statement accounts are translated at an exchange rate that approximates the average for the period. Translation adjustments arising from the use of differing exchange rates from period to period are included as a component of other comprehensive income (loss) within stockholders’ equity. Gains and losses from foreign currency transactions are included in net income for the period.
Pension and Other Postretirement Plans, Pensions, Policy [Policy Text Block]	Defined Benefit Pension Plan Liabilities and expenses for defined benefit pension plans are determined using actuarial methodologies and incorporate significant assumptions, including the interest rate used to discount the future estimated cash flows, the expected long-term rate of return on plan assets, and several assumptions relating to the employee workforce (salary increases, retirement age, and mortality). Unrealized gains and losses related to the Company's defined benefit pension obligations are recognized as a component of other comprehensive income (loss) within stockholders' equity. Gains or losses resulting from plan amendments, curtailments, and settlements are recognized as a component of other non-operating income and expenses ("other, net") in the period of the remeasurement.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company measures the fair value of assets and liabilities on a recurring and nonrecurring basis according to a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of the fair value hierarchy are as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that are accessible at the measurement date; Level 2 inputs include inputs other than Level 1 that are observable, either directly or indirectly, and Level 3 inputs are unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to measurements involving significant unobservable inputs (Level 3). The Company measures the fair values of goodwill, intangible assets and property, buildings and equipment on a nonrecurring basis if required by impairment tests applicable to these assets, as described above.
Other Income and Expense	Other, net Other non-operating income and expenses ("other, net") primarily includes the non-service cost components of net periodic pension cost (benefit) and foreign exchange gains and losses.
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Recently Adopted Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which removes certain exceptions to the general principles of Accounting Standards Codification ("ASC") Topic 740, Income Taxes , and simplifies other aspects of accounting for income taxes. The amendments in this ASU were effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption was permitted in any interim or annual period, with any adjustments reflected as of the beginning of the fiscal year of adoption. The Company adopted this ASU in the first quarter of 2021. The adoption of this guidance did not have a material impact on the consolidated financial statements and notes thereto presented herein.
New Accounting Pronouncements, Policy	Recently Issued Accounting Pronouncements In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , which requires contract assets and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance with ASC Topic 606, Revenue from Contracts with Customers , as if the acquirer had originated the contracts. The amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Management is currently evaluating the impact that the adoption of this accounting standard will have on its consolidated financial statements and notes thereto. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting , which provides optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendments in this Update are effective for all entities as of March 12, 2020 through December 31, 2022. Management does not expect the replacement of London Interbank Offered Rate (LIBOR) and the related adoption of the optional guidance under this accounting standard to have a material impact on the Company's consolidated financial statements and notes thereto. Other pronouncements issued by the FASB or other authoritative accounting standards groups with future effective dates are either not applicable or are not expected to be significant to Wesco’s financial position, results of operations or cash flows.

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following tables disaggregate Wesco’s net sales by segment and geography for the periods presented: Year Ended December 31, (In thousands) 2021 2020 2019 Electrical & Electronic Solutions $ 7,621,263 $ 5,479,760 $ 4,860,541 Communications & Security Solutions 5,715,238 3,323,264 909,496 Utility & Broadband Solutions 4,881,011 3,522,971 2,588,880 Total by segment $ 18,217,512 $ 12,325,995 $ 8,358,917 Year Ended December 31, (In thousands) 2021 2020 2019 United States $ 13,157,866 $ 9,110,453 $ 6,234,119 Canada 2,747,187 1,892,321 1,647,066 Other International (1) 2,312,459 1,323,221 477,732 Total by geography (2) $ 18,217,512 $ 12,325,995 $ 8,358,917 (1) No individual country's net sales are greater than 10% of total net sales. (2) Wesco attributes revenues from external customers to individual countries on the basis of point of sale.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table sets forth the changes in the carrying value of goodwill by reportable segment for the periods presented: EES CSS UBS Total (In thousands) Balance as of January 1, 2020 $ 573,447 $ 235,711 $ 949,882 $ 1,759,040 Adjustments to goodwill for acquisitions (Note 6) (1) (2) (3) 264,538 868,936 250,553 1,384,027 Foreign currency exchange rate changes 15,471 10,853 17,778 44,102 Balance as of December 31, 2020 $ 853,456 $ 1,115,500 $ 1,218,213 $ 3,187,169 Adjustments to goodwill for acquisitions (Note 6) (4) 1,124 8,603 4,215 13,942 Foreign currency exchange rate changes and other 6,378 (2,391) 3,235 7,222 Balance as of December 31, 2021 $ 860,958 $ 1,121,712 $ 1,225,663 $ 3,208,333 (1) Adjustments to goodwill include the final allocation of the purchase price paid to acquire SLS, as disclosed in Note 6, "Acquisitions and Disposals", which is reflected in the EES segment. (2) Adjustments to goodwill include an increase of $33.9 million resulting from the out-of-period adjustment related to inventory cost absorption accounting, as described in Note 2, "Accounting Policies", which affected the EES, CSS and UBS segments by $20.2 million, $2.0 million, and $11.7 million, respectively. (3) Adjustments to goodwill include $26.1 million that was classified as held for sale on the UBS segment as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale". Such amount was disposed in the first quarter of 2021 as part of the Canadian divestitures disclosed in Note 6, "Acquisitions and Disposals". (4) Includes the effect on goodwill of the adjustments to the assets acquired and liabilities assumed in the merger with Anixter since their initial measurement, as described in Note 6, "Acquisitions and Disposals".
Schedule of Intangible Assets by Major Class	The components of intangible assets are as follows: December 31, 2021 December 31, 2020 Life (in years) Gross Carrying Amount (1) Accumulated Amortization (1) Net Gross Carrying Amount (1) Accumulated Amortization (1) Net (In thousands) Intangible assets: Trademarks (2) Indefinite $ 795,065 $ — $ 795,065 $ 833,793 $ — $ 833,793 Customer relationships (3) 10 - 20 1,431,251 (308,180) 1,123,071 1,434,554 (227,585) 1,206,969 Distribution agreements (3) 15 - 19 29,212 (22,714) 6,498 29,212 (21,040) 8,172 Trademarks (2)(3) 1 - 12 38,758 (20,058) 18,700 24,898 (11,415) 13,483 Non-compete agreements 2 4,300 (3,493) 807 4,462 (1,384) 3,078 $ 2,298,586 $ (354,445) $ 1,944,141 $ 2,326,919 $ (261,424) $ 2,065,495 (1) Excludes the original cost and related accumulated amortization of fully-amortized intangible assets. (2) As disclosed in Note 2, "Accounting Policies", the Company assigned remaining estimated useful lives to certain trademarks, including those that previously had indefinite lives. (3) The net carrying amount as of December 31, 2020 excluded $1.0 million of trademarks, $3.3 million of customer relationships and $1.4 million of distribution agreements that were classified as held for sale and disposed in the first quarter of 2021 as part of the Canadian divestitures disclosed in Note 7, "Assets and Liabilities Held For Sale".
Schedule of Expected Amortization Expense	The following table sets forth the remaining estimated amortization expense for intangible assets for the next five years and thereafter: For the year ending December 31, (In thousands) 2022 $ 92,593 2023 83,287 2024 80,827 2025 77,710 2026 60,834 Thereafter 753,825

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2021
Business Acquisition [Line Items]
Business Acquisition, Schedule of Consideration Transferred	The total fair value of consideration transferred for the Merger consisted of the following: (In thousands) Cash portion attributable to common stock outstanding $ 2,476,010 Cash portion attributable to options and restricted stock units outstanding 87,375 Fair value of cash consideration 2,563,385 Common stock consideration 313,512 Series A preferred stock consideration 573,786 Fair value of equity consideration 887,298 Extinguishment of Anixter obligations, including accrued and unpaid interest 1,247,653 Total purchase consideration $ 4,698,336 Supplemental cash flow disclosure related to acquisitions: Cash paid for acquisition $ 3,811,038 Less: Cash acquired (103,463) Cash paid for acquisition, net of cash acquired $ 3,707,575
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table sets forth the allocation of the purchase consideration to the respective fair value of assets acquired and liabilities assumed for the acquisition of Anixter: Preliminary Fair Value Estimates (1) Measurement Period Adjustments Final Purchase Price Allocation (1) Assets (In thousands) Cash and cash equivalents $ 103,463 $ — $ 103,463 Trade accounts receivable 1,309,894 (8,928) 1,300,966 Other receivables 116,386 — 116,386 Inventories 1,424,768 (14,906) 1,409,862 Prepaid expenses and other current assets 53,462 14,202 67,664 Property, buildings and equipment 215,513 (3,792) 211,721 Operating lease assets 262,238 18,047 280,285 Intangible assets 1,832,700 5,365 1,838,065 Goodwill 1,367,981 16,356 1,384,337 Other assets 114,258 25,589 139,847 Total assets $ 6,800,663 $ 51,933 $ 6,852,596 Liabilities Accounts payable $ 920,163 $ (1,239) $ 918,924 Accrued payroll and benefit costs 69,480 — 69,480 Short-term debt and current portion of long-term debt 13,225 — 13,225 Other current liabilities 221,574 12,745 234,319 Long-term debt 77,822 (205) 77,617 Operating lease liabilities 200,286 17,017 217,303 Deferred income taxes 392,165 (15,111) 377,054 Other noncurrent liabilities 207,612 38,726 246,338 Total liabilities $ 2,102,327 $ 51,933 $ 2,154,260 Fair value of net assets acquired, including goodwill and intangible assets $ 4,698,336 $ — $ 4,698,336 (1) The preliminary fair value estimates are as of June 30, 2020. As disclosed above, the Company finalized its purchase price allocation during the measurement period.
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination	The following table sets forth the identifiable intangible assets and their estimated weighted-average useful lives: Identifiable Intangible Assets Estimated Weighted-Average Estimated Useful Life in Years (In thousands) Customer relationships $ 1,098,900 19 Trademarks 735,000 Indefinite Non-compete agreements 4,165 2 Total identifiable intangible assets $ 1,838,065
Business Acquisition, Pro Forma Information	Pro Forma Financial Information The following unaudited pro forma financial information presents combined results of operations for the periods presented, as if the Company had completed the Merger on January 1, 2019. The unaudited pro forma financial information includes adjustments to amortization and depreciation for intangible assets and property, buildings and equipment, adjustments to interest expense for the additional indebtedness incurred to complete the acquisition (including the amortization of debt discount and issuance costs), transaction costs, change in control and severance costs, dividends accrued on the Series A preferred stock, compensation expense associated with the Wesco phantom stock unit awards described in Note 14, "Employee Benefit Plans", as well as the respective income tax effects of such adjustments. For the year ended December 31, 2020, adjustments totaling $7.0 million increased the unaudited pro forma net income attributable to common stockholders, and adjustments totaling $201.3 million decreased the unaudited pro forma net income attributable to common stockholders for the year ended December 31, 2019. The unaudited pro forma financial information does not reflect any cost savings, operating synergies or revenue enhancements that Wesco may achieve as a result of its acquisition of Anixter, the costs to integrate the operations of Wesco and Anixter or the costs necessary to achieve these cost savings, operating synergies and revenue enhancements. The unaudited pro forma financial information presented below is not necessarily indicative of consolidated results of operations of the combined business had the acquisition occurred at the beginning of the respective periods, nor is it necessarily indicative of future results of operations of the combined company. Year Ended (In thousands) December 31, 2020 December 31, 2019 Pro forma net sales $ 16,016,902 $ 17,204,472 Pro forma net income attributable to common stockholders 119,839 285,100

ASSETS AND LIABILITIES HELD F_2

ASSETS AND LIABILITIES HELD FOR SALE (Tables)	12 Months Ended
	Dec. 31, 2021
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations	The assets and liabilities classified as held for sale were as follows: As of December 31, 2020 (In thousands) Trade accounts receivable, net $ 4,258 Inventories 16,438 Prepaid expenses and other current assets 395 Property, buildings and equipment, net 263 Operating lease assets 1,938 Intangible assets, net 5,722 Goodwill 26,059 Total assets held for sale $ 55,073 Accounts payable $ 3,639 Other current liabilities 541 Operating lease liabilities 1,537 Total liabilities held for sale $ 5,717

PROPERTY, BUILDINGS AND EQUIP_2

PROPERTY, BUILDINGS AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The following table sets forth the components of property, buildings and equipment: As of December 31, 2021 2020 (1) (In thousands) Buildings and leasehold improvements $ 165,691 $ 169,873 Furniture, fixtures and equipment (2) 281,864 272,704 Software costs (2) 250,447 229,279 698,002 671,856 Accumulated depreciation and amortization (365,345) (312,106) 332,657 359,750 Land 25,600 26,409 Construction in progress 20,755 12,998 $ 379,012 $ 399,157 (1) The components of property, buildings and equipment as of December 31, 2020 exclude a total of $0.3 million that is classified as held for sale, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) The furniture, fixtures and equipment, and software costs components of property, buildings and equipment as of December 31, 2020 reflect a $6.4 million reclassification between the previously reported amounts of those components to conform to the current period's presentation.

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Lease, Cost [Table Text Block]	The following table sets forth the Company's total lease cost, which is recorded as a component of selling, general and administrative expenses, for the periods presented: Year Ended December 31, (In thousands) 2021 2020 2019 Operating lease cost $ 169,892 $ 127,725 $ 73,613 Short-term lease cost 3,578 494 90 Variable lease cost 49,464 36,230 23,385 Total lease cost $ 222,934 $ 164,449 $ 97,088
Schedule of Cash Flow, Supplemental Disclosures	The following table sets forth supplemental cash flow information related to operating leases for the periods presented: Year Ended December 31, (In thousands) 2021 2020 2019 Operating cash flows from operating leases $ 153,626 $ 117,106 $ 75,775 Right-of-use assets obtained in exchange for new operating lease liabilities 157,523 121,207 60,586
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The following table sets forth the maturities of the Company's operating lease liabilities and reconciles the respective undiscounted payments to the operating lease liabilities in the Consolidated Balance Sheet as of December 31, 2021: (In thousands) 2022 $ 152,919 2023 126,012 2024 94,494 2025 64,875 2026 48,813 Thereafter 136,123 Total undiscounted operating lease payments 623,236 Less: imputed interest (79,107) Total operating lease liabilities $ 544,129
AssetsAndLiabilitiesLesseeTableTextBlock	The following table sets forth supplemental balance sheet information related to operating leases for the periods presented: As of December 31, (In thousands) 2021 2020 (1) Operating lease assets $ 530,863 $ 534,705 Current operating lease liabilities (2) 129,881 128,322 Noncurrent operating lease liabilities 414,248 414,889 Total operating lease liabilities $ 544,129 $ 543,211 (1) Operating lease assets and liabilities of $1.9 million and $2.1 million, respectively, are classified as held for sale as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) Current operating lease liabilities are recorded as a component of other current liabilities in the Consolidated Balance Sheets.

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Debt	The following table sets forth Wesco’s outstanding indebtedness: As of December 31, 2021 2020 (In thousands) International lines of credit $ 7,354 $ 29,575 Accounts Receivable Securitization Facility 1,270,000 950,000 Revolving Credit Facility 596,959 250,000 5.375% Senior Notes due 2021 — 500,000 5.50% Anixter Senior Notes due 2023 58,636 58,636 5.375% Senior Notes due 2024 — 350,000 6.00% Anixter Senior Notes due 2025 4,173 4,173 7.125% Senior Notes due 2025 1,500,000 1,500,000 7.250% Senior Notes due 2028, less debt discount of $8,088 and $9,332 in 2021 and 2020, respectively 1,316,912 1,315,668 Finance lease obligations 18,563 17,931 Total debt 4,772,597 4,975,983 Plus: Fair value adjustments to the Anixter Senior Notes 957 1,650 Less: Unamortized debt issuance costs (62,484) (78,850) Less: Short-term debt and current portion of long-term debt (9,528) (528,830) Total long-term debt $ 4,701,542 $ 4,369,953
Schedule of Maturities of Long-term Debt	The following table sets forth the aggregate principal repayment requirements for all indebtedness for the next five years and thereafter, as of December 31, 2021: (In thousands) 2022 $ 9,528 2023 64,831 2024 1,272,914 2025 2,105,486 2026 2,010 Thereafter 1,325,916 Total payments on debt $ 4,780,685 Debt discount (8,088) Total debt $ 4,772,597

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The following table sets forth the components of income before income taxes by jurisdiction: Year Ended December 31, 2021 2020 2019 (In thousands) United States $ 396,769 $ 26,031 $ 198,566 Foreign 185,143 96,811 83,495 Income before income taxes $ 581,912 $ 122,842 $ 282,061
Schedule of Components of Income Tax Expense	The following table sets forth the components of the provision for income taxes: Year Ended December 31, 2021 2020 2019 (In thousands) Current income taxes: Federal $ 107,919 $ 25,605 $ 31,695 State 30,206 11,322 8,616 Foreign 55,670 19,414 6,347 Total current income taxes 193,795 56,341 46,658 Deferred income taxes: Federal (62,302) (17,913) 6,774 State (12,327) (7,264) 1,846 Foreign (3,656) (8,361) 4,585 Total deferred income taxes (78,285) (33,538) 13,205 Provision for income taxes $ 115,510 $ 22,803 $ 59,863
Schedule of Effective Income Tax Rate Reconciliation	The following table sets forth the reconciliation between the federal statutory income tax rate and the effective tax rate: Year Ended December 31, 2021 2020 2019 Federal statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal income tax benefit 2.0 1.4 3.1 Deemed repatriation of undistributed foreign earnings — — (1.3) Tax effect of intercompany financing (3.2) (13.4) (5.5) Unrecognized tax benefits 2.5 2.1 (0.4) Nondeductible expenses 0.6 5.7 0.7 Change in valuation allowance (2.8) 1.8 0.6 Other (0.2) — 3.0 Effective tax rate 19.9 % 18.6 % 21.2 %
Schedule of Deferred Tax Assets and Liabilities	The following table sets forth deferred tax assets and liabilities: As of December 31, 2021 2020 (In thousands) Assets Liabilities Assets Liabilities Accounts receivable $ 18,612 $ — $ 17,560 $ — Inventories 13,302 — 14,793 — Depreciation of property, buildings and equipment — 45,397 — 60,687 Operating leases 142,964 141,686 134,377 136,477 Amortization of intangible assets — 549,536 — 540,520 Employee benefits 36,410 — 53,040 — Stock-based compensation 12,281 — 14,061 — Prepaid royalty payments 34,866 — — — Disallowed business interest expense (1) 11,163 — 2,755 — Tax loss carryforwards 39,876 — 36,923 — Foreign tax credit carryforwards 51,632 — 55,637 — Other (1) 26,666 8,137 24,888 6,286 Deferred income taxes before valuation allowance 387,772 744,756 354,034 743,970 Valuation allowance (46,269) — (60,629) — Total deferred income taxes $ 341,503 $ 744,756 $ 293,405 $ 743,970
Summary of Income Tax Examinations	The Company is under examination by tax authorities in various jurisdictions and remains subject to examination until the applicable statutes of limitation expire. The statutes of limitation for the material jurisdictions in which the Company files income tax returns remain open as follows: United States — Federal 2017 and forward United States — Material States 2017 and forward Canada 2012 and forward UK 2016 and forward Australia 2017 and forward
Summary of Income Tax Contingencies	The following table sets forth the reconciliation of gross unrecognized tax benefits: As of December 31, 2021 2020 2019 (In thousands) Beginning balance January 1 $ 68,075 $ 54 $ 1,293 Additions for current year tax positions 39,841 14,009 — Additions for prior year tax positions 8,422 — — Additions for acquired tax positions — 68,048 — Reductions for prior year tax positions (3,853) (43) — Settlements (118) — (1,290) Lapse in statute of limitations (3,837) (15,886) — Foreign currency exchange rate changes (1,239) 1,893 51 Ending balance December 31 $ 107,291 $ 68,075 $ 54

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the details of basic and diluted earnings per share: Year Ended December 31, 2021 2020 2019 (In thousands, except per share data) Net income attributable to WESCO International, Inc. $ 465,382 $ 100,560 $ 223,426 Less: Preferred stock dividends 57,408 30,139 — Net income attributable to common stockholders $ 407,974 $ 70,421 $ 223,426 Weighted-average common shares outstanding used in computing basic earnings per share 50,300 46,174 43,104 Common shares issuable upon exercise of dilutive equity awards 1,730 451 383 Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share 52,030 46,625 43,487 Earnings per share attributable to common stockholders Basic $ 8.11 $ 1.53 $ 5.18 Diluted $ 7.84 $ 1.51 $ 5.14

EMPLOYEE BENEFIT PLANS - (Table

EMPLOYEE BENEFIT PLANS - (Tables)	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Schedule of Net Funded Status [Table Text Block]	The following table presents the changes in benefit obligations, plan assets and funded status for the defined benefit plans: Domestic Plans Foreign Plans Total (In thousands) 2021 2020 2021 2020 2021 2020 Change in Projected Benefit Obligation Beginning balance $ 332,484 $ — $ 486,855 $ 134,852 $ 819,339 $ 134,852 Impact of acquisition (1) — 317,893 — 301,206 — 619,099 Service cost 3,033 1,763 12,140 9,029 15,173 10,792 Interest cost 8,219 4,787 9,801 7,162 18,020 11,949 Participant contributions — — 846 728 846 728 Actuarial (gain) loss, including assumption changes (10,649) 12,911 (35,483) 14,044 (46,132) 26,955 Benefits paid from plan assets (8,988) (4,222) (11,343) (9,008) (20,331) (13,230) Benefits paid from Company assets (527) (547) (461) (448) (988) (995) Curtailment (3,900) (101) (32,680) — (36,580) (101) Plan amendment — — (104) (37) (104) (37) Settlement (17,889) — (219) (1,235) (18,108) (1,235) Foreign currency exchange rate changes — — (5,256) 30,562 (5,256) 30,562 Ending balance $ 301,783 $ 332,484 $ 424,096 $ 486,855 $ 725,879 $ 819,339 Change in Plan Assets at Fair Value Beginning balance $ 355,287 $ — $ 365,718 $ 103,385 $ 721,005 $ 103,385 Impact of acquisition (1) — 324,292 — 218,644 — 542,936 Actual return on plan assets 24,432 35,217 19,661 23,947 44,093 59,164 Participant contributions — — 846 728 846 728 Employer contributions 17,889 — 10,240 6,838 28,129 6,838 Benefits paid (8,988) (4,222) (11,343) (9,008) (20,331) (13,230) Settlement (17,889) — (218) (1,235) (18,107) (1,235) Foreign currency exchange rate changes — — (3,123) 22,419 (3,123) 22,419 Ending balance $ 370,731 $ 355,287 $ 381,781 $ 365,718 $ 752,512 $ 721,005 Funded Status $ 68,948 $ 22,803 $ (42,315) $ (121,137) $ 26,633 $ (98,334) Amounts Recognized in the Consolidated Balance Sheets Other assets $ 68,948 $ 40,921 $ 4,818 $ 179 $ 73,766 $ 41,100 Other current liabilities — (18,118) (437) (471) (437) (18,589) Other noncurrent liabilities — — (46,696) (120,845) (46,696) (120,845) Net amount recognized $ 68,948 $ 22,803 $ (42,315) $ (121,137) $ 26,633 $ (98,334) Weighted Average Assumptions Used to Determine Benefit Obligations Discount rate 2.9 % 2.6 % 2.4 % 2.0 % 2.6 % 2.2 % Rate of compensation increase — % 3.8 % 3.4 % 3.2 % 3.4 % 3.4 % (1) The Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020, as disclosed in Note 6, "Acquisitions and Disposals". For all defined benefit plans assumed as part of the merger with Anixter, the projected benefit obligation and fair value of plan assets were remeasured as of the acquisition date.
Schedule of Net Benefit Costs [Table Text Block]	The following tables set forth the components of net periodic pension (benefit) cost for the Company's defined benefit plans: Domestic Plans (1) Foreign Plans (1) Total (In thousands) 2021 2020 2019 2021 2020 2019 2021 2020 2019 Components of Net Periodic Pension (Benefit) Cost Service cost $ 3,033 $ 1,763 $ — $ 12,140 $ 9,029 $ 4,602 $ 15,173 $ 10,792 $ 4,602 Interest cost 8,219 4,787 — 9,801 7,162 4,362 18,020 11,949 4,362 Expected return on plan assets (17,097) (8,395) — (17,834) (11,659) (5,695) (34,931) (20,054) (5,695) Recognized actuarial gain — — — 90 — (63) 90 — (63) Curtailment (3,900) — — (32,680) — — (36,580) — — Settlement 290 — — (59) (144) — 231 (144) — Net periodic pension (benefit) cost $ (9,455) $ (1,845) $ — $ (28,542) $ 4,388 $ 3,206 $ (37,997) $ 2,543 $ 3,206 (1) As described above, the Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020. The Company began recognizing the associated net periodic pension (benefit) cost as of the acquisition date.
Defined Benefit Plan, Assumptions [Table Text Block]	The following weighted-average actuarial assumptions were used to determine net periodic pension (benefit) cost: Domestic Plans (1) Foreign Plans (1) Total 2021 2020 2019 2021 2020 2019 2021 2020 2019 Discount rate 2.6 % 2.9 % — % 2.0 % 2.2 % 4.0 % 2.3 % 2.5 % 4.0 % Expected return on plan assets 5.3 % 5.5 % — % 4.9 % 5.2 % 6.4 % 5.1 % 5.3 % 6.4 % Rate of compensation increase 3.8 % 3.8 % — % 3.2 % 3.4 % 3.8 % 3.4 % 3.5 % 3.8 % (1) As described above, the Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020. The Company began using the related assumptions as of the acquisition date.
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)	The following table sets forth the changes and the end of year components of accumulated other comprehensive (income) loss for the defined benefit plans: Year Ended December 31, (In thousands) 2021 2020 Changes to Balance: Beginning balance, before tax effect $ (3,062) $ 8,890 Prior service credit arising in current year (100) (37) Net actuarial gain arising in current year (93,064) (12,154) Recognized actuarial gain (90) — Curtailment 36,580 (101) Settlement (231) 144 Foreign currency exchange rate changes 1,179 196 Ending balance, before tax effect $ (58,788) $ (3,062) As of December 31, (In thousands) 2021 2020 Components of Balance: Prior service credit $ (137) $ (37) Net actuarial gain (58,651) (3,025) Ending balance, before tax effect (58,788) (3,062) Tax effect 13,605 562 Ending balance, after tax effect $ (45,183) $ (2,500)
Schedule of Expected Benefit Payments [Table Text Block]	The following benefit payments, which reflect expected future service, are expected to be paid as follows: (In thousands) Domestic Plans Foreign Plans Total 2022 $ 11,215 $ 9,430 $ 20,645 2023 11,743 9,654 21,397 2024 12,385 10,294 22,679 2025 12,890 11,065 23,955 2026 13,508 11,525 25,033 2027 to 2031 73,410 84,171 157,581
Defined Benefit Plan, Plan Assets, Allocation [Table Text Block]	The asset mixes and the asset allocation guidelines for the Domestic Plans and Foreign Plans are summarized as follows: Domestic Plans Allocation Guidelines December 31, 2021 Min Target Max Equities 10.8 % 5 % 10 % 15 % Debt securities: Domestic treasuries 36.1 — 34 — Corporate bonds 25.7 — 40 — Other 7.6 3 7 13 Total debt securities 69.4 81 Property/real estate 19.0 3 8 13 Other 0.8 — 1 — 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2021 Min Target Max Equities 39.2 % 25 % 39 % 48 % Debt securities: Corporate bonds 4.5 — — 37 Other 43.5 26 48 65 Total debt securities 48.0 48 Property/real estate 4.4 2 5 8 Insurance products 4.9 5 5 5 Other 3.5 3 3 13 100.0 % 100 % Domestic Plans Allocation Guidelines December 31, 2020 Min Target Max Equities 38.6 % 30 % 37 % 45 % Debt securities: Domestic treasuries 22.2 — 24 40 Corporate bonds 6.7 — 8 40 Other 15.6 9 14 19 Total debt securities 44.5 46 Property/real estate 14.8 9 16 23 Other 2.1 — 1 5 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2020 Min Target Max Equities 38.1 % 25 % 41 % 48 % Debt securities: Corporate bonds 5.9 % 1 1 37 Other 40.6 26 44 65 Total debt securities 46.5 45 Property/real estate 4.8 2 6 8 Insurance products 5.4 5 5 5 Other 5.2 3 3 12 100.0 % 100 %
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	The following tables set forth the fair value of assets by asset category for the Domestic Plans and Foreign Plans: December 31, 2021 (In thousands) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 40,102 $ 40,102 Debt securities: Domestic treasuries — — — 133,672 133,672 Corporate bonds — — — 95,198 95,198 Other — — — 28,246 28,246 Property/real estate — — — 70,648 70,648 Other 2,865 — — — 2,865 Total investments in Domestic Plans $ 2,865 $ — $ — $ 367,866 $ 370,731 Foreign Plans Equities $ — $ — $ — $ 149,707 $ 149,707 Debt securities: Corporate bonds — — — 17,328 17,328 Other — — — 165,863 165,863 Property/real estate — — — 16,632 16,632 Insurance products — 18,781 — — 18,781 Other 1,248 — — 12,222 13,470 Total investments in Foreign Plans $ 1,248 $ 18,781 $ — $ 361,752 $ 381,781 Total Equities $ — $ — $ — $ 189,809 $ 189,809 Debt securities: Domestic treasuries — — — 133,672 133,672 Corporate bonds — — — 112,526 112,526 Other — — — 194,109 194,109 Property/real estate — — — 87,280 87,280 Insurance products — 18,781 — — 18,781 Other 4,113 — — 12,222 16,335 Total investments $ 4,113 $ 18,781 $ — $ 729,618 $ 752,512 (1) Investments measured at fair value using the NAV per share practical expedient have not been classified in the fair value hierarchy. The amounts presented in the tables above are intended to reconcile the fair value hierarchy to the total fair value of plan assets. December 31, 2020 (In thousands) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 137,098 $ 137,098 Debt securities: Domestic treasuries — — — 78,808 78,808 Corporate bonds — — — 23,824 23,824 Other — — — 55,547 55,547 Property/real estate — — — 52,708 52,708 Other 7,302 — — — 7,302 Total investments in Domestic Plans $ 7,302 $ — $ — $ 347,985 $ 355,287 Foreign Plans Equities $ — $ — $ — $ 139,537 139,537 Debt securities: Corporate bonds — — — 21,677 21,677 Other — — — 148,469 148,469 Property/real estate — — — 17,365 17,365 Insurance products — 19,611 — — 19,611 Other 747 — — 18,312 19,059 Total investments in Foreign Plans $ 747 $ 19,611 $ — $ 345,360 $ 365,718 Total Equities $ — $ — $ — $ 276,635 $ 276,635 Debt securities: Domestic treasuries — — — 78,808 78,808 Corporate bonds — — — 45,501 45,501 Other — — — 204,016 204,016 Property/real estate — — — 70,073 70,073 Insurance products — 19,611 — — 19,611 Other 8,049 — — 18,312 26,361 Total investments $ 8,049 $ 19,611 $ — $ 693,345 $ 721,005 (1) Investments measured at fair value using the NAV per share practical expedient have not been classified in the fair value hierarchy. The amounts presented in the tables above are intended to reconcile the fair value hierarchy to the total fair value of plan assets.

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights Award Activity	The following table sets forth a summary of stock-settled stock appreciation rights and related information for the periods presented: Year Ended December 31, 2021 2020 2019 Awards Weighted-Average Weighted-Average Aggregate Awards Weighted-Average Awards Weighted-Average Beginning of year 2,161,556 $ 60.48 2,337,049 $ 59.72 2,351,633 $ 59.26 Granted 139,592 77.05 262,091 48.32 213,618 54.63 Exercised (916,906) 60.70 (391,339) 47.11 (113,099) 35.01 Canceled (13,854) 54.42 (46,245) 65.93 (115,103) 65.27 End of year 1,370,388 62.09 6.1 $ 95,246 2,161,556 60.48 2,337,049 59.72 Exercisable at end of year 1,001,708 $ 62.79 5.3 $ 68,920 1,630,891 $ 62.72 1,723,370 $ 59.00
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following table sets forth the weighted-average assumptions used to estimate the fair value of stock-settled stock appreciation rights granted during the periods presented: Year Ended December 31, 2021 2020 2019 Stock-settled stock appreciation rights granted 139,592 262,091 213,618 Risk free interest rate 0.8% 1.4% 2.5% Expected life (in years) 7 5 5 Expected volatility 41% 30% 29%
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	The following table sets forth a summary of time-based restricted stock units and related information for the periods presented: Year Ended December 31, 2021 2020 2019 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 921,495 $ 43.15 363,729 $ 60.00 327,798 $ 57.87 Granted 314,480 77.81 656,717 37.44 192,106 54.13 Vested (232,152) 44.10 (83,253) 69.17 (136,777) 46.52 Forfeited (29,661) 63.86 (15,698) 56.79 (19,398) 59.62 Unvested at end of year 974,162 $ 53.48 921,495 $ 43.15 363,729 $ 60.00 The following table sets forth a summary of performance-based awards and related information for the periods presented: Year Ended December 31, 2021 2020 2019 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 305,269 $ 52.61 195,305 $ 60.24 138,896 $ 59.33 Granted 122,812 76.76 158,756 49.56 126,874 54.64 Vested (22,371) 62.80 (25,909) 78.04 (25,696) 42.44 Forfeited (24,891) 61.26 (22,883) 69.39 (44,769) 52.11 Unvested at end of year 380,819 $ 59.23 305,269 $ 52.61 195,305 $ 60.24

BUSINESS SEGMENTS (Tables)

BUSINESS SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table sets forth financial information by reportable segment for the periods presented: (In thousands) Year Ended December 31, 2021 EES CSS UBS Corporate Total Net sales $ 7,621,263 $ 5,715,238 $ 4,881,011 $ — $ 18,217,512 Income from operations 542,059 395,343 412,740 (548,269) 801,873 Adjusted EBITDA 604,461 480,820 428,367 (337,965) 1,175,683 Adjusted EBITDA Margin % 7.9 % 8.4 % 8.8 % 6.5 % Supplemental information: Depreciation and amortization $ 55,998 $ 82,870 $ 22,447 $ 37,239 $ 198,554 Capital expenditures 4,469 3,197 5,207 41,873 54,746 Year Ended December 31, 2020 (In thousands) EES CSS UBS Corporate Total Net sales $ 5,479,760 $ 3,323,264 $ 3,522,971 $ — $ 12,325,995 Income from operations 260,207 217,163 231,702 (362,034) 347,038 Adjusted EBITDA 308,327 280,656 265,593 (194,259) 660,317 Adjusted EBITDA Margin % 5.6 % 8.4 % 7.5 % 5.4 % Supplemental information: Depreciation and amortization $ 35,811 $ 37,765 $ 22,380 $ 25,644 $ 121,600 Capital expenditures 7,081 1,495 12,834 35,261 56,671 Year Ended December 31, 2019 (In thousands) EES CSS UBS Corporate Total Net sales $ 4,860,541 $ 909,496 $ 2,588,880 $ — $ 8,358,917 Income from operations 261,788 43,835 184,931 (144,337) 346,217 Adjusted EBITDA 291,473 51,067 198,745 (110,769) 430,516 Adjusted EBITDA Margin % 6.0 % 5.6 % 7.7 % 5.2 % Supplemental information: Depreciation and amortization $ 28,569 $ 7,155 $ 13,583 $ 12,800 $ 62,107 Capital expenditures 20,405 3,093 6,460 14,109 44,067 The following table sets forth total assets by reportable segment for the periods presented: As of December 31, 2021 (In thousands) EES CSS UBS Corporate (1) Total Total assets $ 4,098,335 $ 4,601,132 $ 3,266,231 $ 652,001 $ 12,617,699 As of December 31, 2020 (In thousands) EES CSS UBS Corporate (1) Total Total assets $ 3,726,855 $ 4,275,611 $ 2,947,406 $ 930,342 $ 11,880,214 (1) Total assets for Corporate primarily consist of cash and cash equivalents, deferred income taxes, fixed assets and right-of-use assets associated with operating leases.
Long-lived Assets by Geographic Areas	The following table sets forth tangible long-lived assets, which include property, buildings and equipment, and operating lease assets, by geographic area: As of December 31, 2021 2020 (In thousands) United States $ 698,942 $ 693,807 Canada 141,380 146,620 Other International (1) 69,553 93,435 Total $ 909,875 $ 933,862 (1) No individual other international country's tangible long-lived assets are material.
Reconciliation of Assets from Segment to Consolidated	The following table sets forth total assets by reportable segment for the periods presented: As of December 31, 2021 (In thousands) EES CSS UBS Corporate (1) Total Total assets $ 4,098,335 $ 4,601,132 $ 3,266,231 $ 652,001 $ 12,617,699 As of December 31, 2020 (In thousands) EES CSS UBS Corporate (1) Total Total assets $ 3,726,855 $ 4,275,611 $ 2,947,406 $ 930,342 $ 11,880,214

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Tables)	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Allowance for Doubtful Accounts	Balance at Charged to Charged to Balance at of period earnings accounts (1) Deductions (2) end of period Allowance for expected credit losses (In thousands) Year Ended December 31, 2021 $ 23,909 $ 12,944 $ 13,669 $ (8,800) $ 41,722 Year Ended December 31, 2020 25,443 11,701 5,160 (18,395) 23,909 Year Ended December 31, 2019 24,468 7,006 52 (6,083) 25,443 (1) For the years ended December 31, 2021 and 2020, the amount charged to other accounts primarily relates to the acquisition of Anixter. (2) Includes a reduction in the allowance for expected credit losses due to the write-off of trade accounts receivable. Balance at Charged to Charged to Balance at of period earnings accounts (1) Deductions (2) end of period Allowance for deferred tax assets (In thousands) Year Ended December 31, 2021 $ 60,629 $ 1,115 $ 1,791 $ (17,266) $ 46,269 Year Ended December 31, 2020 5,854 1,900 52,875 — 60,629 Year Ended December 31, 2019 4,072 1,745 37 — 5,854 (1) For the year ended December 31, 2020, the amount charged to other accounts includes $59.3 million that was recorded in connection with the acquisition of Anixter. (2) For the year ended December 31, 2021, deductions primarily include a decrease in the valuation allowance recorded against deferred tax assets related to foreign tax credit carryforwards.

Accounting Policies (Details)

Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)branches	Dec. 31, 2020USD ($)		Dec. 31, 2019USD ($)
Nontrade Receivables	$ 219,100	$ 136,700
Accounts Receivable, Allowance for Credit Loss, Current	41,700	23,900
Accounts Receivable, Credit Loss Expense (Reversal)	12,900	10,100		$ 7,000
Inventory Valuation Reserves	50,300	28,700
Inventory Write-down	37,100	15,700		$ 10,000
Intangible Assets, Net (Including Goodwill)	4,000,000
Self Insurance Reserve	$ 30,600	$ 27,900
Change in Accounting Estimate, Description	As of December 31, 2020, $39.1 million of the trademarks impacted by the master brand strategy had indefinite lives and $9.5 million had remaining estimated useful lives ranging from 3 to 8 years. As disclosed further below, the Company continually evaluates whether events or circumstances have occurred that would require a change to the estimated useful lives of indefinite-lived and definite lived intangible assets. When such a change is warranted, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. Accordingly, during the second quarter of 2021, the Company changed the estimated useful lives of the trademarks affected by the new corporate brand strategy to coincide with the expected period of time to migrate such sub-brands to the master brand architecture. The Company assigned remaining estimated useful lives to these trademarks, including those that previously had indefinite lives, ranging from less than one year to 5 years.
Supplier volume rebate income percentage	1.40%	1.10%		1.20%
Number of Locations | branches	800
Property, buildings and equipment, net	$ 379,012	$ 399,157	[1]
Finite-Lived Intangible Assets, Amortization Expense	119,600	66,500		$ 35,500
Intangible Assets, Amortization Period
Finite-Lived Intangible Assets, Amortization Expense	$ 32,000
Leasehold Improvements
Property, Plant and Equipment, Estimated Useful Lives	five to forty years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Estimated Useful Lives	two to ten years
Software and Software Development Costs [Member]
Property, Plant and Equipment, Estimated Useful Lives	three to seven years
Land, Buildings and Improvements
Property, buildings and equipment, net	$ 133,600
Cost of Goods Sold
Out-of-Period Adjustment		18,900
Net Income
Out-of-Period Adjustment		14,400
Inventories
Out-of-Period Adjustment		60,300
Goodwill
Out-of-Period Adjustment		33,900
Deferred Income Tax Liability
Out-of-Period Adjustment		$ 12,000
Minimum
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year
Maximum
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	20 years
[1]	The components of property, buildings and equipment as of December 31, 2020 exclude a total of $0.3 million that is classified as held for sale, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) The furniture, fixtures and equipment, and software costs components of property, buildings and equipment as of December 31, 2020 reflect a $6.4 million reclassification between the previously reported amounts of those components to conform to the current period's presentation.

REVENUE (Details)

REVENUE (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	[1]	$ 18,217,512	$ 12,325,995	$ 8,358,917
Selling, general and administrative expense		2,791,641	1,859,028	1,173,137
Contract with Customer, Asset, before Allowance for Credit Loss		33,400	19,400
Deferred Revenue		35,500	24,300
EES
Disaggregation of Revenue [Line Items]
Net sales		7,621,263	5,479,760	4,860,541
CSS
Disaggregation of Revenue [Line Items]
Net sales		5,715,238	3,323,264	909,496
UBS
Disaggregation of Revenue [Line Items]
Net sales		4,881,011	3,522,971	2,588,880
UNITED STATES
Disaggregation of Revenue [Line Items]
Net sales		13,157,866	9,110,453	6,234,119
Canada
Disaggregation of Revenue [Line Items]
Net sales		2,747,187	1,892,321	1,647,066
Other International
Disaggregation of Revenue [Line Items]
Net sales	[2]	2,312,459	1,323,221	477,732
Shipping and Handling [Member]
Disaggregation of Revenue [Line Items]
Selling, general and administrative expense		$ 248,300	$ 149,300	$ 71,700
[1]	(2) Wesco attributes revenues from external customers to individual countries on the basis of point of sale.
[2]	(1) No individual country's net sales are greater than 10% of total net sales.

REVENUE Variable Consideration

REVENUE Variable Consideration (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue, Information Used to Assess Variable Consideration Constraint	433.4 million	269.5 million	106.6 million
Contract with Customer, Refund Liability	$ 38.8	$ 38.9
Disaggregation of Revenue [Line Items]
Contract with Customer, Refund Liability	$ 38.8	$ 38.9

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Notional Amount	$ 188.6	$ 111.9
Senior Notes [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	2,880.7	3,730.1
Long-term Debt, Fair Value	$ 3,118	$ 4,084.7

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - TEXTUALS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-Lived Intangible Assets, Amortization Expense	$ 119,600	$ 66,500	$ 35,500
Goodwill [Line Items]
Disposal Group, Intangible Assets	5,722
Trademarks
Goodwill [Line Items]
Disposal Group, Intangible Assets	1,000
Customer Relationships
Goodwill [Line Items]
Disposal Group, Intangible Assets	3,300
Distribution agreements
Goodwill [Line Items]
Disposal Group, Intangible Assets	$ 1,400

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF GOODWILL (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Beginning balance January 1	$ 3,187,169	$ 1,759,040
Ending balance December 31	3,208,333	3,187,169
Goodwill, Acquired During Period	13,942	1,384,027
Goodwill, Foreign Currency Translation Gain (Loss)	7,222	44,102
Disposal Group, Including Discontinued Operation, Goodwill, Current	26,100
Goodwill
Goodwill [Roll Forward]
Out-of-Period Adjustment		33,900
EES
Goodwill [Roll Forward]
Beginning balance January 1	853,456	573,447
Ending balance December 31	860,958	853,456
Goodwill, Acquired During Period	1,124	264,538
Goodwill, Foreign Currency Translation Gain (Loss)	6,378	15,471
Goodwill, Period Increase (Decrease)	20,200
UBS
Goodwill [Roll Forward]
Beginning balance January 1	1,218,213	949,882
Ending balance December 31	1,225,663	1,218,213
Goodwill, Acquired During Period	4,215	250,553
Goodwill, Foreign Currency Translation Gain (Loss)	3,235	17,778
Goodwill, Period Increase (Decrease)	11,700
CSS
Goodwill [Roll Forward]
Beginning balance January 1	1,115,500	235,711
Ending balance December 31	1,121,712	1,115,500
Goodwill, Acquired During Period	8,603	868,936
Goodwill, Foreign Currency Translation Gain (Loss)	(2,391)	$ 10,853
Goodwill, Period Increase (Decrease)	$ 2,000

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF INTANGIBLE ASSETS BY MAJOR CLASS (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization		$ (354,445)	$ (261,424)
Intangible Assets Gross Excluding Goodwill		2,298,586	2,326,919
Intangible Assets, Net (Excluding Goodwill)		1,944,141	2,065,495
Finite-Lived Intangible Assets, Amortization Expense		119,600	66,500	$ 35,500
Intangible Assets, Amortization Period
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense		32,000
Trademarks
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	38,758	24,898
Finite-Lived Intangible Assets, Accumulated Amortization	[1]	(20,058)	(11,415)
Finite-Lived Intangible Assets, Net	[1]	18,700	13,483
Customer relationships
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	1,431,251	1,434,554
Finite-Lived Intangible Assets, Accumulated Amortization	[1]	(308,180)	(227,585)
Finite-Lived Intangible Assets, Net	[1]	1,123,071	1,206,969
Distribution agreements
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	29,212	29,212
Finite-Lived Intangible Assets, Accumulated Amortization	[1]	(22,714)	(21,040)
Finite-Lived Intangible Assets, Net	[1]	6,498	8,172
Non-compete agreements
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		4,300	4,462
Finite-Lived Intangible Assets, Accumulated Amortization		(3,493)	(1,384)
Finite-Lived Intangible Assets, Net		807	3,078
Trademarks
Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Gross		$ 795,065	$ 833,793
Minimum
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		1 year
Minimum | Trademarks
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		1 year
Minimum | Customer relationships
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		10 years
Minimum | Distribution agreements
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		15 years
Maximum
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		20 years
Maximum | Trademarks
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		12 years
Maximum | Customer relationships
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		20 years
Maximum | Distribution agreements
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		19 years
Maximum | Non-compete agreements
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		2 years
[1]	The net carrying amount as of December 31, 2020 excluded $1.0 million of trademarks, $3.3 million of customer relationships and $1.4 million of distribution agreements that were classified as held for sale and disposed in the first quarter of 2021 as part of the Canadian divestitures disclosed in Note 7, "Assets and Liabilities Held For Sale".

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF EXPECTED AMORTIZATION EXPENSE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2021	$ 92,593
2022	83,287
2023	80,827
2024	77,710
2025	60,834
Thereafter	753,825
Finite-Lived Intangible Assets, Amortization Expense	$ 119,600	$ 66,500	$ 35,500

ACQUISITIONS (Details)

ACQUISITIONS (Details)	12 Months Ended
	Dec. 31, 2021USD ($)countriesnumberOfCities$ / sharesshares	Dec. 31, 2020USD ($)shares	Jun. 22, 2020USD ($)$ / sharesshares	Dec. 31, 2019shares	Dec. 31, 2018shares
Business Acquisition [Line Items]
Preferred stock, shares issued | shares	21,612	21,612		0	0
Preferred stock, par value | $ / shares	$ 0.01
Number of Cities in which an Entity Operates | numberOfCities	300
Anixter International [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Jun. 22, 2020
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period	$ 8,000,000,000
Common stock, shares issued | shares			0.2397
Preferred stock, shares issued | shares			0.6356
Common Stock			$ 0.01
Preferred Stock, Dividend Rate, Percentage	10.625%
Preferred stock, par value | $ / shares			$ 25,000
Business Acquisition, Description of Acquired Entity	Anixter was a leading distributor of network and security solutions, electrical and electronic solutions, and utility power solutions with locations in over 300 cities across approximately 50 countries, and 2019 annual sales of more than $8 billion.
Business Combination, Reason for Business Combination	The Merger brought together two companies with highly compatible capabilities and characteristics. The combination of Wesco and Anixter created an enterprise with scale and has afforded the Company the opportunity to digitize its business and expand its services portfolio and supply chain offerings.
Additional countries (in countries) | countries	50
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 9,500,000,000	$ 4,500,000,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	580,600,000	180,000,000
Business Acquisition, Transaction Costs	$ 158,500,000	$ 132,200,000
Anixter International [Member] | Cash [Member]
Business Acquisition [Line Items]
Business Acquisition, Share Price | $ / shares			$ 72.82

SCHEDULE OF CONSIDERATION TRANS

SCHEDULE OF CONSIDERATION TRANSFERRED (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 0	$ 3,707,575	$ 27,597
Anixter International [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	3,811,038
Payment to Acquire Business, Fair Value of Cash Consideration	2,563,385
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	887,298
Payment for Debt Extinguishment or Debt Prepayment Cost	1,247,653
Business Combination, Consideration Transferred	4,698,336
Cash Acquired from Acquisition	103,463
Payments to Acquire Businesses, Net of Cash Acquired	3,707,575
Anixter International [Member] | Common Stock
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	2,476,010
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	313,512
Anixter International [Member] | Restricted Stock
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	87,375
Anixter International [Member] | Preferred Stock
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	$ 573,786

SCHEDULE OF ASSUMED ASSETS AND

SCHEDULE OF ASSUMED ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Jun. 22, 2021	Dec. 31, 2020	Jun. 22, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 3,208,333		$ 3,187,169		$ 1,759,040
Business Combination, Goodwill Recognized, Description	During the second quarter of 2021, the Company finalized its allocation of the purchase consideration to the respective fair values of assets acquired and liabilities assumed in the acquisition of Anixter. As the Company obtained additional information during the measurement period, it recorded adjustments to its preliminary estimates of fair value, which were as of June 30, 2020. As presented in the table below, the net impact of these measurement period adjustments was an increase to goodwill of $16.4 million.
Anixter International [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		$ 103,463		$ 103,463
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables		1,300,966		1,309,894
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other		116,386		116,386
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory		(14,906)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory		1,409,862		1,424,768
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets		14,202
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment		(3,792)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets		67,664		53,462
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		211,721		215,513
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Operating Lease Assets		18,047
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Operating Lease Assets		280,285		262,238
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles		5,365
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		1,838,065		1,832,700
Goodwill, Purchase Accounting Adjustments		16,356
Goodwill		1,384,337		1,367,981
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsNoncurrentAssets		25,589
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets		139,847		114,258
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAssets		51,933
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		6,852,596		6,800,663
wcc:BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable		(1,239)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable		918,924		920,163
Business Combination, Recongized Identifiable Assets Acquired and Liabilities Assumed, Accrued Payroll and Benefit Costs		69,480		69,480
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt		13,225		13,225
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCurrentLiabilitiesOther		12,745
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other		234,319		221,574
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNoncurrentLiabilitiesLongTermDebt		(205)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt		77,617		77,822
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Operating Lease Liabilities		17,017
Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation		217,303		200,286
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Income Taxes		(15,111)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities		377,054		392,165
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Noncurrent Liabilities		38,726
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other		246,338		207,612
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsLiabilities		51,933
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		2,154,260		2,102,327
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net		4,698,336		$ 4,698,336
wcc:BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsReceivable		$ (8,928)

ANIXTER IDENTIFIABLE INTANGIBLE

ANIXTER IDENTIFIABLE INTANGIBLES (Details) - Anixter International [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Jun. 22, 2021	Jun. 22, 2020
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 1,838,065	$ 1,832,700
Trademarks
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets		735,000
Customer-Related Intangible Assets
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		1,098,900
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	19 years
Noncompete Agreements [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ 4,165
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	2 years

ACQUISITIONS - Anixter Pro Form

ACQUISITIONS - Anixter Pro Forma (Details) - Anixter International [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	$ 119,839	$ 285,100
Business Acquisition, Pro Forma Revenue	16,016,902	$ 17,204,472
Revenue
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Revenue	7,000
Net Income
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	$ 201,300

ACQUISITIONS AND DISPOSALS - Ca

ACQUISITIONS AND DISPOSALS - Canadian Divestitures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Disposal Group, Revenue		$ 110,000	$ 120,000
Proceeds from Divestiture of Businesses	$ 56,000
Gain (Loss) on Disposition of Business	(8,927)	(19,816)	$ 0
Anixter International [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Revenue	16,016,902	17,204,472
Business Acquisition, Pro Forma Net Income (Loss)	119,839	285,100
Business Acquisition, Transaction Costs	158,500	$ 132,200
Anixter International [Member] | Revenue
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Revenue	7,000
Anixter International [Member] | Net Income
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	$ 201,300

ACQUISITIONS AND DISPOSALS- SYL

ACQUISITIONS AND DISPOSALS- SYLVANIA (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)countries
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 0	$ 3,707,575	$ 27,597
Sylvania Lighting Services Corp. [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition			Mar. 5, 2019
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period			$ 100,000
Number of Employees Employed by the Entity | countries			220
Business Acquisition, Goodwill, Expected Tax Deductible Amount			$ 11,600
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets			34,812
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			7,070
Payments to Acquire Businesses, Net of Cash Acquired			$ 27,742

ASSET AND LIABILITIES HELD FOR

ASSET AND LIABILITIES HELD FOR SALE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Revenue	$ 110,000	$ 120,000
Disposal Group, Accounts, Notes and Loans Receivable, Net			$ 4,258
Disposal Group, Inventory			16,438
Disposal Group, Prepaid and Other Assets			395
Disposal Group, Property, Plant and Equipment	$ 300		263
Disposal Group, Operating Lease Assets			1,938
Disposal Group, Intangible Assets			5,722
Disposal Group, Goodwill			26,059
Disposal Group, Assets			55,073
Disposal Group, Accounts Payable			3,639
Disposal Group, Other Liabilities, Current			541
Disposal Group, Operating Lease Liabilities			1,537
Disposal Group, Liabilities			$ 5,717

PROPERTY, BUILDINGS AND EQUIP_3

PROPERTY, BUILDINGS AND EQUIPMENT - SCHEDULE OF PROPERTY, BUILDINGS AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ (365,345)	$ (312,106)	[1]
Property, buildings and equipment, net	379,012	399,157	[1]
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, before Accumulated Amortization	39,600	2,000
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization	8,800	1,100
Disposal Group, Property, Plant and Equipment	263	300
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	165,691	169,873	[1]
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	281,864	272,704	[1]
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	250,447	229,279	[1]
Depreciable [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	698,002	671,856	[1]
Property, buildings and equipment, net	332,657	359,750	[1]
Land
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	25,600	26,409	[1]
Construction in progress
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	$ 20,755	$ 12,998	[1]
[1]	The components of property, buildings and equipment as of December 31, 2020 exclude a total of $0.3 million that is classified as held for sale, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) The furniture, fixtures and equipment, and software costs components of property, buildings and equipment as of December 31, 2020 reflect a $6.4 million reclassification between the previously reported amounts of those components to conform to the current period's presentation.

PROPERTY, BUILDINGS AND EQUIP_4

PROPERTY, BUILDINGS AND EQUIPMENT - PROPERTY, BUILDINGS AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 61,600	$ 40,800		$ 15,900
Capitalized software amortization	27,500	14,300		$ 10,600
Unamortized software cost	103,400	117,500
Property, Plant and Equipment [Line Items]
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, before Accumulated Amortization	39,600	2,000
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization	8,800	1,100
Finance Lease, Right-of-Use Asset, Accumulated Amortization	12,400	7,900
Finance Lease, Right-of-Use Asset, before Accumulated Amortization	31,900	25,700
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	$ 250,447	229,279	[1]
Software and Software Development Costs [Member] | Revision of Prior Period, Reclassification, Adjustment
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross		$ 6,400
[1]	The components of property, buildings and equipment as of December 31, 2020 exclude a total of $0.3 million that is classified as held for sale, as disclosed in Note 7, "Assets and Liabilities Held For Sale". (2) The furniture, fixtures and equipment, and software costs components of property, buildings and equipment as of December 31, 2020 reflect a $6.4 million reclassification between the previously reported amounts of those components to conform to the current period's presentation.

LEASES (Details)

LEASES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	6 years	6 years 1 month 6 days
Operating Lease, Weighted Average Discount Rate, Percent	4.20%	4.60%
Option to Extend Lessee's Operating Lease, Lease Payments	$ 26.9
Lessee, Operating Lease, Lease Not yet Commenced, Payments	$ 67.1
Lessee, Operating Lease, Lease Not yet Commenced, Description	These operating leases, which are not recorded in the Consolidated Balance Sheet as of December 31, 2021, will commence in 2022 with lease terms of 1.5 to 10.5 year

LEASES Supplemental balance she

LEASES Supplemental balance sheet information (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset		$ 530,863	$ 534,705	[1]
Operating Lease, Liability, Noncurrent		414,248	414,889	[1]
Operating Lease, Liability		544,129	543,211	[1]
Disposal Group, Operating Lease Assets		$ 1,938
Disposal Group, Including Discontinued Operation, ST and LT Operating Lease Liabilities			$ 2,100
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	[2]	Other Liabilities, Current	Other Liabilities, Current	[1]
[1]	Operating lease assets and liabilities of $1.9 million and $2.1 million, respectively, are classified as held for sale as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale".
[2]	Current operating lease liabilities are recorded as a component of other current liabilities in the Consolidated Balance Sheets.

LEASES Lease, Cost (Details)

LEASES Lease, Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 169,892	$ 127,725	$ 73,613
Short-term Lease, Cost	3,578	494	90
Variable Lease, Cost	49,464	36,230	23,385
Lease, Cost	$ 222,934	$ 164,449	$ 97,088

LEASES Supplemental Cash Flow I

LEASES Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating Lease, Payments	$ 153,626	$ 117,106	$ 75,775
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 157,523	$ 121,207	$ 60,586

LEASES Lessee, Operating Lease,

LEASES Lessee, Operating Lease, Liability, Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	[1]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 152,919
Lessee, Operating Lease, Liability, Payments, Due Year Two	126,012
Lessee, Operating Lease, Liability, Payments, Due Year Three	94,494
Lessee, Operating Lease, Liability, Payments, Due Year Four	64,875
Lessee, Operating Lease, Liability, Payments, Due Year Five	48,813
Lessee, Operating Lease, Liability, Payments, Due after Year Five	136,123
Lessee, Operating Lease, Liability, Payments, Due	623,236
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(79,107)
Operating Lease, Liability	$ 544,129	$ 543,211
[1]	Operating lease assets and liabilities of $1.9 million and $2.1 million, respectively, are classified as held for sale as of December 31, 2020, as disclosed in Note 7, "Assets and Liabilities Held For Sale".

DEBT - SCHEDULE OF DEBT (Detail

DEBT - SCHEDULE OF DEBT (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	$ 8,088
Total debt	4,772,597	$ 4,975,983
Debt Instrument, Unamortized Premium	957	1,650
Debt Issuance Costs, Net	(62,484)	(78,850)
Less current and short-term portion	(9,528)	(528,830)
Total Long-term Debt, Excluding Current Maturities	$ 4,701,542	$ 4,369,953
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Total Long-term Debt, Excluding Current Maturities	Total Long-term Debt, Excluding Current Maturities
Foreign Line of Credit [Member]
Debt Instrument [Line Items]
Long-term debt	$ 7,354	$ 29,575
Accounts receivable securitization facility
Debt Instrument [Line Items]
Long-term debt	1,270,000	950,000
Revolving credit facility
Debt Instrument [Line Items]
Long-term debt	596,959	250,000
Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	0	500,000
Senior Notes Due 2023
Debt Instrument [Line Items]
Long-term debt	58,636	58,636
Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	0	350,000
Senior Notes Due 2025
Debt Instrument [Line Items]
Long-term debt	4,173	4,173
A7125 Senior Notes Due 2025
Debt Instrument [Line Items]
Long-term debt	1,500,000	1,500,000
A7250 Senior Notes Due 2028
Debt Instrument [Line Items]
Long-term debt	1,316,912	1,315,668
Debt Instrument, Unamortized Discount	$ 8,088	$ 9,332

DEBT (Details)

DEBT (Details) - USD ($)	12 Months Ended							24 Months Ended
	Jun. 14, 2026	Jun. 14, 2025	Jun. 14, 2024	Jun. 14, 2023	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 14, 2028	Dec. 14, 2020
Debt Instrument [Line Items]
Characteristics of Securitizations or Asset-backed Financing Arrangements that are Accounted for as Sale					Under the Receivables Facility, Wesco sells, on a continuous basis, an undivided interest in all domestic accounts receivable to Wesco Receivables, a wholly owned special purpose entity (the “SPE”). The SPE sells, without recourse, a senior undivided interest in the receivables to financial institutions for cash while maintaining a subordinated undivided interest in the receivables, in the form of overcollateralization. Since Wesco maintains control of the transferred receivables, the transfers do not qualify for “sale” treatment. As a result, the transferred receivables remain on the balance sheet, and Wesco recognizes the related secured borrowing. Wesco has agreed to continue servicing the sold receivables for the third-party conduits and financial institutions at market rates; accordingly, no servicing asset or liability has been recorded.
Accounts Receivable from Securitization					$ 1,270,000,000	$ 950,000,000
Percentage of principal amount of Senior Notes accelerated under default					0.25
Debt Issuance Costs, Net					(62,484,000)	$ (78,850,000)
Long-term Debt, Gross					$ 4,780,685,000
Foreign Line of Credit [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate					3.35%	3.40%
Long-term debt					$ 7,354,000	$ 29,575,000
Accounts Receivable Securitization Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date					Jun. 22, 2023
Debt Instrument, Basis Spread on Variable Rate					1.20%		0.95%
Accounts Receivable Eligible for Securitization					$ 1,728,100,000	1,476,100,000
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate					1.23%
Line of Credit Facility, Opportunity to Increase Borrowing Capacity						1,400,000,000
Debt Instrument, Unused Borrowing Capacity, Amount					$ 1,200,000,000	1,025,000,000	$ 600,000,000
Long-term debt					$ 1,270,000,000	950,000,000
Debt Instrument, Interest Rate, Stated Percentage					0.50%
Commitment Fee							0.45%
Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date					Jun. 15, 2024
Long-term debt					$ 0	350,000,000
Debt Instrument, Interest Rate, Stated Percentage					5.375%
Debt Instrument, Face Amount					$ 350,000,000
Debt Instrument, Redemption Price, Percentage					101.344%
Gain (Loss) on Extinguishment of Debt					$ 6,900,000
Gain (Loss) on Extinguishment of Debt, before Write off of Debt Issuance Cost					4,700,000
Write off of Deferred Debt Issuance Cost					2,200,000
5.50% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt					$ 58,600,000
Debt Instrument, Interest Rate, Stated Percentage					5.50%
Debt Instrument, Face Amount					$ 350,000,000
Senior Notes tender offer consideration per $1,000 principal amount					50
6.00% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt					$ 4,200,000
Debt Instrument, Interest Rate, Stated Percentage					6.00%
Debt Instrument, Face Amount					$ 250,000,000
Senior Notes consent fee per $1,000 principal amount					2.50
Senior Notes tender offer consideration per $1,000 principal amount					$ 1,012.5
A7125 Senior Notes Due 2025
Debt Instrument [Line Items]
Debt Instrument, Maturity Date					Jun. 15, 2025
Debt Instrument, Issuance Date					Jun. 12, 2020
Long-term debt					$ 1,500,000,000	1,500,000,000
Debt Instrument, Interest Rate, Stated Percentage					7.125%
Debt Instrument, Face Amount					$ 1,500,000,000
Discount percentage of par value					100.00%
Deferred Finance Costs, Gross					$ 33,100,000
Debt Instrument, Redemption Price, Percentage					35.00%
A7125 Senior Notes Due 2025 | Forecast [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		100.00%	101.781%	103.563%
A7250 Senior Notes Due 2028
Debt Instrument [Line Items]
Debt Instrument, Maturity Date					Jun. 15, 2028
Debt Instrument, Issuance Date					Jun. 12, 2020
Long-term debt					$ 1,316,912,000	1,315,668,000
Debt Instrument, Interest Rate, Stated Percentage					7.25%
Debt Instrument, Face Amount					$ 1,325,000,000
Discount percentage of par value					99.244%
Deferred Finance Costs, Gross					$ 29,300,000
Debt Instrument, Redemption Price, Percentage					35.00%
Long-term Debt, Gross					$ 1,325,000,000
A7250 Senior Notes Due 2028 | Forecast [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	101.208%	102.417%	103.625%					100.00%
Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date					Dec. 15, 2021
Long-term debt					$ 0	500,000,000
Debt Instrument, Interest Rate, Stated Percentage					5.375%
Debt Instrument, Face Amount					$ 500,000,000
Debt Instrument, Redemption Price, Percentage					100.00%
Write off of Deferred Debt Issuance Cost					$ 1,000,000
Revolving credit facility
Debt Instrument [Line Items]
Line of Credit Facility, Opportunity to Increase Borrowing Capacity					500,000,000
Debt Instrument, Unused Borrowing Capacity, Amount					$ 1,100,000,000				$ 1,200,000,000
Debt Instrument, Interest Rate During Period					1.54%
Debt Instrument, Increase, Additional Borrowings					$ 2,353,400,000	1,197,900,000
Debt Instrument, Decrease, Repayments					2,006,400,000	948,000,000
Long-term debt					596,959,000	250,000,000
Line of Credit Facility, Remaining Borrowing Capacity					564,800,000	801,500,000
Revolving credit facility | Letter of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Unused Borrowing Capacity, Amount					$ 175,000,000
Accounts Receivable Securitization Facility Amended
Debt Instrument [Line Items]
Debt Instrument, Maturity Date					Jun. 21, 2024
Debt Instrument, Basis Spread on Variable Rate					1.15%
Line of Credit Facility, Opportunity to Increase Borrowing Capacity						$ 1,500,000,000
Debt Instrument, Unused Borrowing Capacity, Amount					$ 1,300,000,000
Debt Instrument, Interest Rate, Stated Percentage					0.00%
Minimum | Foreign Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity					$ 600,000
Maximum | Foreign Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity					$ 31,000,000
London Interbank Offered Rate (LIBOR) [Member] | Minimum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					1.25%
London Interbank Offered Rate (LIBOR) [Member] | Maximum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					1.50%
Prime Rate [Member] | Minimum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					0.25%
Prime Rate [Member] | Maximum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					0.50%

DEBT - SCHEDULE OF MATURITIES O

DEBT - SCHEDULE OF MATURITIES OF LONG-TERM DEBT (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
2021	$ 9,528
2022	64,831
2023	1,272,914
2024	2,105,486
2025	2,010
Thereafter	1,325,916
Total payments on debt	4,780,685
Debt discount on convertible debentures	(8,088)
Debt and Lease Obligation	$ 4,772,597	$ 4,975,983

STOCKHOLDERS' EQUITY (Details)

STOCKHOLDERS' EQUITY (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	20,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred stock, shares issued	21,612	21,612	0	0
Common Stock
Class of Stock [Line Items]
Common Stock, Shares Authorized	210,000,000	210,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Class B
Class of Stock [Line Items]
Common Stock, Shares Authorized	20,000,000	20,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Series A Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	25,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred Stock, Dividend Payment Rate, Variable	10.325
Preferred Stock, Liquidation Preference Per Share	$ 25,000
Preferred Stock, Dividend Rate, Percentage	10.625%
Preferred stock, shares issued	21,612
Depositary Share [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	21,611,534

INCOME TAXES - ADDITIONAL INFOR

INCOME TAXES - ADDITIONAL INFORMATION (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Amortization of intangible assets	$ 549,536	$ 540,520
Deferred Tax Assets, Tax Deferred Expense, Other	6,900	8,200
Deferred Tax Assets, Operating Loss Carryforwards	39,876	36,923
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	51,632	55,637
Deferred Tax Assets, Valuation Allowance	46,269	60,629
Unrecognized Tax Benefits	107,291	68,075	$ 54	$ 1,293
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	36,100	29,100	100
Decrease in Unrecognized Tax Benefits is Reasonably Possible	14,300
Interest related to uncertain tax positions	900	300	$ (800)
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	6,400	5,500
Undistributed Earnings of Foreign Subsidiaries	1,851,600
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries	82,200
Unrecognized Tax Benefits, Income Tax Penalties Accrued	4,900	1,500
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability	60,700
Deferred Tax Asset, Interest Carryforward	11,163	2,755
Unrecognized Tax Benefits, Income Tax Penalties Expense	$ 3,400
Income Tax Examination, Description	On October 22, 2021, one of the Company's Mexican affiliates received a tax assessment from the Mexican tax authorities related to its 2012 income tax return in the amount of approximately $26.0 million. The Company believes the assessment is without merit and has appealed it. The Company expects any potential liability remaining after availing itself of available administrative and judicial appeals to be immaterial to its consolidated financial statements and, accordingly, has not recorded a reserve
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 17,300	30,100
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	4,400	2,400
Deferred Tax Asset, Interest Carryforward	6,400
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	3,200
Deferred Tax Asset, Interest Carryforward	4,700
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	35,500	34,500
Operating Loss Carryforwards, Valuation Allowance	22,100	22,300
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 51,600	$ 55,600

INCOME TAXES - SCHEDULE OF INCO

INCOME TAXES - SCHEDULE OF INCOME BEFORE INCOME TAX, DOMESTIC AND FOREIGN (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
United States	$ 396,769	$ 26,031	$ 198,566
Foreign	185,143	96,811	83,495
Income before income taxes	$ 581,912	$ 122,842	$ 282,061

INCOME TAXES - SCHEDULE OF COMP

INCOME TAXES - SCHEDULE OF COMPONENTS OF INCOME TAX EXPENSE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current taxes
Federal	$ 107,919	$ 25,605	$ 31,695
State	30,206	11,322	8,616
Foreign	55,670	19,414	6,347
Total current	193,795	56,341	46,658
Deferred taxes
Federal	(62,302)	(17,913)	6,774
State	(12,327)	(7,264)	1,846
Foreign	(3,656)	(8,361)	4,585
Total deferred	(78,285)	(33,538)	13,205
Income tax expense	$ 115,510	$ 22,803	$ 59,863

INCOME TAXES - SCHEDULE OF EFFE

INCOME TAXES - SCHEDULE OF EFFECTIVE INCOME TAX RATE RECONCILIATION (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal tax benefit	2.00%	1.40%	3.10%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent	0.00%	0.00%	(1.30%)
Effective Income Tax Rate Reconciliation, Deduction, Percent	(3.20%)	(13.40%)	(5.50%)
Unrecognized tax benefits	2.50%	2.10%	(0.40%)
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent	0.60%	5.70%	0.70%
Foreign Income Tax Expense (Benefit), Continuing Operations	(2.80%)	1.80%	0.60%
Other	(0.20%)	0.00%	3.00%
Effective income tax rate	19.90%	18.60%	21.20%

INCOME TAXES - SCHEDULE OF DEFE

INCOME TAXES - SCHEDULE OF DEFERRED TAX ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred Tax Assets, Net [Abstract]
Accounts receivable	$ 18,612	$ 17,560
Deferred Tax Assets, Inventory	13,302	14,793
Deferred Tax Assets, Property, Plant and Equipment	0	0
Deferred Tax Assets, Property, Plant and Equipment	142,964	134,377
Deferred Tax Assets, Goodwill and Intangible Assets	0	0
Employee benefits	36,410	53,040
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	12,281	14,061
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Reserves	34,866	0
Deferred Tax Asset, Interest Carryforward	11,163	2,755
Tax loss carryforwards	39,876	36,923
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	51,632	55,637
Other	26,666	24,888
Deferred taxes, Assets	341,503	293,405
Deferred Tax Liabilities [Abstract]
Depreciation	45,397	60,687
Deferred Tax Liabilities, Leasing Arrangements	141,686	136,477
Amortization of intangible assets	549,536	540,520
Other	8,137	6,286
Deferred Tax Assets, Gross	387,772	354,034
Deferred Tax Assets, Valuation Allowance	(46,269)	(60,629)
Deferred Tax Liabilities, Gross	744,756	743,970
State and Local Jurisdiction [Member]
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset, Interest Carryforward	6,400
Tax loss carryforwards	$ 4,400	$ 2,400

INCOME TAXES - SCHEDULE OF IN_2

INCOME TAXES - SCHEDULE OF INCOME TAX CONTINGENCIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Additions for tax positions of prior years	$ 8,422	$ 0	$ 0
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	1,239
Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation		1,893	51
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance January 1	68,075	54	1,293
Additions based on tax positions related to the current year	39,841	14,009	0
Unrecognized Tax Benefits, Increase Resulting from Acquisition	0	68,048	0
Reductions for tax positions of prior years	(3,853)	(43)	0
Settlements	(118)	0	(1,290)
Lapse in statute of limitations	(3,837)	(15,886)	0
Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation		1,893	51
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	(1,239)
Ending balance December 31	$ 107,291	$ 68,075	$ 54

EARNINGS PER SHARE - SCHEDULE O

EARNINGS PER SHARE - SCHEDULE OF EARNINGS PER SHARE, BASIC AND DILUTED (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2021
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock	$ 0	$ 0	$ 150,000
Stock Repurchase Program, Authorized Amount	$ 400,000	300,000	$ 300,000
Stock Repurchase Program Expiration Date	Dec. 31, 2020
Treasury Stock, Shares, Acquired			3,455,584
Preferred Stock Dividends, Income Statement Impact	$ 57,408	$ 30,139	$ 0
Weighted average common shares outstanding used in computing basic earnings per share	50,300,000	46,174,000	43,104,000
Common shares issuable upon exercise of dilutive stock options	1,730,000	451,000	383,000
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share	52,030,000	46,625,000	43,487,000
Earnings Per Share attributable to WESCO International, Inc.
Basic	$ 8.11	$ 1.53	$ 5.18
Diluted	$ 7.84	$ 1.51	$ 5.14
Net Income (Loss) Available to Common Stockholders, Basic	$ 407,974	$ 70,421	$ 223,426
Net Income attributable to WESCO International, Inc.	$ 465,382	100,560	$ 223,426
Treasury Stock, Common [Member]
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock		$ 275,000
Treasury Stock, Common, Shares				3,455,584
Treasury Stock, Shares, Acquired		5,459,030

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Payments for Repurchase of Common Stock	$ 0	$ 0	$ 150,000
Treasury Stock, Shares, Acquired			3,455,584
Stock Appreciation Rights (SARs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share	0	1,800,000	1,700,000
Treasury Stock, Common [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Treasury Stock, Common, Shares				3,455,584
Payments for Repurchase of Common Stock		$ 275,000
Treasury Stock, Shares, Acquired		5,459,030

EMPLOYEE BENEFIT PLANS TEXTUALS

EMPLOYEE BENEFIT PLANS TEXTUALS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)numberOfPlans	Dec. 31, 2020USD ($)numberOfPlans	Dec. 31, 2019USD ($)
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

EMPLOYEE BENEFIT PLANS Benefit

EMPLOYEE BENEFIT PLANS Benefit Obligations, Plan Assets, and Funded Status (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation		$ 725,879	$ 819,339	$ 134,852
Defined Benefit Plan, Benefit Obligation, Business Combination	[1]	0	619,099
Service Cost		15,173	10,792	4,602
Interest cost		18,020	11,949	4,362
Participant contributions		846	728
Actuarial (gain) loss		(46,132)	26,955
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(20,331)	(13,230)
DefinedBenefitPlanBenefitsPaidFromCompanyAssets		(988)	(995)
Curtailment		(36,580)	(101)
Plan Amendment		(104)	(37)
Settlement		(18,108)	(1,235)
Foreign Currency Translation Gain (Loss)		(5,256)	30,562
Defined Benefit Plan, Plan Assets, Amount		752,512	721,005	103,385
Defined Benefit Plan, Plan Assets, Business Combination	[1]	0	542,936
Actual return on plan assets		44,093	59,164
Participant contributi		846	728
Company contributions		28,129	6,838
Defined Benefit Plan, Plan Assets, Benefits Paid		(20,331)	(13,230)
Settlement		(18,107)	(1,235)
Foreign Currency Translation Gain (Loss)		(3,123)	22,419
Funded status		26,633	(98,334)
Assets for Plan Benefits, Defined Benefit Plan		73,766	41,100
Current liabilities		(437)	(18,589)
Non-current liabilities		$ (46,696)	$ (120,845)
Discount rate		2.60%	2.20%
Average salary increases		3.40%	3.40%
United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation		$ 301,783	$ 332,484	0
Defined Benefit Plan, Benefit Obligation, Business Combination	[1]	0	317,893
Service Cost		3,033	1,763	0
Interest cost		8,219	4,787	0
Participant contributions		0	0
Actuarial (gain) loss		(10,649)	12,911
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(8,988)	(4,222)
DefinedBenefitPlanBenefitsPaidFromCompanyAssets		(527)	(547)
Curtailment		(3,900)	(101)
Plan Amendment		0	0
Settlement		(17,889)	0
Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Plan Assets, Amount		370,731	355,287	0
Defined Benefit Plan, Plan Assets, Business Combination	[1]	0	324,292
Actual return on plan assets		24,432	35,217
Participant contributi		0	0
Company contributions		17,889	0
Defined Benefit Plan, Plan Assets, Benefits Paid		(8,988)	(4,222)
Settlement		(17,889)	0
Foreign Currency Translation Gain (Loss)		0	0
Funded status		68,948	22,803
Assets for Plan Benefits, Defined Benefit Plan		68,948	40,921
Current liabilities		0	(18,118)
Non-current liabilities		$ 0	$ 0
Discount rate		2.90%	2.60%
Average salary increases		0.00%	3.80%
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation		$ 424,096	$ 486,855	134,852
Defined Benefit Plan, Benefit Obligation, Business Combination	[1]	0	301,206
Service Cost		12,140	9,029	4,602
Interest cost		9,801	7,162	4,362
Participant contributions		846	728
Actuarial (gain) loss		(35,483)	14,044
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(11,343)	(9,008)
DefinedBenefitPlanBenefitsPaidFromCompanyAssets		(461)	(448)
Curtailment		(32,680)	0
Plan Amendment		(104)	(37)
Settlement		(219)	(1,235)
Foreign Currency Translation Gain (Loss)		(5,256)	30,562
Defined Benefit Plan, Plan Assets, Amount		381,781	365,718	$ 103,385
Defined Benefit Plan, Plan Assets, Business Combination	[1]	0	218,644
Actual return on plan assets		19,661	23,947
Participant contributi		846	728
Company contributions		10,240	6,838
Defined Benefit Plan, Plan Assets, Benefits Paid		(11,343)	(9,008)
Settlement		(218)	(1,235)
Foreign Currency Translation Gain (Loss)		(3,123)	22,419
Funded status		(42,315)	(121,137)
Assets for Plan Benefits, Defined Benefit Plan		4,818	179
Current liabilities		(437)	(471)
Non-current liabilities		$ (46,696)	$ (120,845)
Discount rate		2.40%	2.00%
Average salary increases		3.40%	3.20%
[1]	he Company assumed the Domestic Plans and certain foreign plans in connection with the acquisition of Anixter on June 22, 2020, as disclosed in Note 6, "Acquisitions and Disposals". For all defined benefit plans assumed as part of the merger with Anixter, the projected benefit obligation and fair value of plan assets were remeasured as of the acquisition date.

EMPLOYEE BENEFIT PLANS Pension

EMPLOYEE BENEFIT PLANS Pension Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Service Cost	$ 15,173	$ 10,792	$ 4,602
Interest cost	18,020	11,949	4,362
Expected return on plan assets	(34,931)	(20,054)	(5,695)
Recognized actuarial gain	90	0	(63)
Defined Benefit Plan, Amortization of Gain (Loss)	(90)	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	(36,580)	0	0
Settlement	231	(144)	0
Total net periodic pension (benefit) cost	(37,997)	2,543	3,206
United States
Defined Benefit Plan Disclosure
Service Cost	3,033	1,763	0
Interest cost	8,219	4,787	0
Expected return on plan assets	(17,097)	(8,395)	0
Recognized actuarial gain	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	(3,900)	0	0
Settlement	290	0	0
Total net periodic pension (benefit) cost	(9,455)	(1,845)	0
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Service Cost	12,140	9,029	4,602
Interest cost	9,801	7,162	4,362
Expected return on plan assets	(17,834)	(11,659)	(5,695)
Recognized actuarial gain	90	0	(63)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	(32,680)	0	0
Settlement	(59)	(144)	0
Total net periodic pension (benefit) cost	$ (28,542)	$ 4,388	$ 3,206

EMPLOYEE BENEFIT PLANS Assumpti

EMPLOYEE BENEFIT PLANS Assumptions (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate	2.30%	2.50%	4.00%
Expected Long-term Rate of Return on Plan Assets	5.10%	5.30%	6.40%
Rate of Compensation Increase	3.40%	3.50%	3.80%
Foreign Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate	2.00%	2.20%	4.00%
Expected Long-term Rate of Return on Plan Assets	4.90%	5.20%	6.40%
Rate of Compensation Increase	3.20%	3.40%	3.80%
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate	2.60%	2.90%	0.00%
Expected Long-term Rate of Return on Plan Assets	5.30%	5.50%	0.00%
Rate of Compensation Increase	3.80%	3.80%	0.00%

EMPLOYEE BENEFIT PLANS - AOCI (

EMPLOYEE BENEFIT PLANS - AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	$ (58,788)	$ (3,062)	$ 8,890
Prior Service Cost (Credit), before Tax	(100)	(37)
Defined Benefit Plan, Amortization of Gain (Loss)	(90)	0
Actuarial (Gain) Loss Arising During Period, before Tax	(93,064)	(12,154)
Curtailment	36,580	(101)
Settlement	(231)	144
Foreign currency translation Gain Loss	1,179	196
Prior Service Cost (Credit), before Tax	(137)	(37)
Actuarial (Gain) Loss, before Tax	(58,651)	(3,025)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	13,605	562
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	$ (45,183)	$ (2,500)

EMPLOYEE BENEFIT PLANS Benefi_2

EMPLOYEE BENEFIT PLANS Benefit payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One	$ 20,645
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	21,397
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	22,679
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	23,955
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	25,033
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	157,581
Defined Benefit Plan, Plan Assets, Payment for Settlement	18,107	$ 1,235
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One		18,100
Defined Benefit Plan, Plan Assets, Payment for Settlement	17,900
United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One	11,215
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	11,743
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	12,385
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	12,890
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	13,508
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	73,410
Defined Benefit Plan, Plan Assets, Payment for Settlement	17,889	0
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One	9,430
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	9,654
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	10,294
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	11,065
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	11,525
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	84,171
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 218	$ 1,235

EMPLOYEE BENEFIT PLANS Asset al

EMPLOYEE BENEFIT PLANS Asset allocations (Details)	Dec. 31, 2021	Dec. 31, 2020
United States
Defined Benefit Plan Disclosure
Total investments	100.00%	100.00%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100.00%	100.00%
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	100.00%	100.00%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100.00%	100.00%
Defined Benefit Plan, Equity Securities | United States
Defined Benefit Plan Disclosure
Total investments	10.80%	38.60%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	10.00%	37.00%
Defined Benefit Plan, Equity Securities | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%	30.00%
Defined Benefit Plan, Equity Securities | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	15.00%	45.00%
Defined Benefit Plan, Equity Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	39.20%	38.10%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	39.00%	41.00%
Defined Benefit Plan, Equity Securities | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	25.00%	25.00%
Defined Benefit Plan, Equity Securities | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	48.00%	48.00%
US Treasury and Government | United States
Defined Benefit Plan Disclosure
Total investments	36.10%	22.20%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	34.00%	24.00%
US Treasury and Government | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	0.00%
US Treasury and Government | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	40.00%
Corporate Debt Securities | United States
Defined Benefit Plan Disclosure
Total investments	25.70%	6.70%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	40.00%	8.00%
Corporate Debt Securities | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	0.00%
Corporate Debt Securities | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	40.00%
Corporate Debt Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4.50%	5.90%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	1.00%
Corporate Debt Securities | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	1.00%
Corporate Debt Securities | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	37.00%	37.00%
Other Debt Obligations | United States
Defined Benefit Plan Disclosure
Total investments	7.60%	15.60%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	7.00%	14.00%
Other Debt Obligations | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	3.00%	9.00%
Other Debt Obligations | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	13.00%	19.00%
Other Debt Obligations | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	43.50%	40.60%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	48.00%	44.00%
Other Debt Obligations | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	26.00%	26.00%
Other Debt Obligations | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	65.00%	65.00%
Defined Benefit Plan, Debt Security | United States
Defined Benefit Plan Disclosure
Total investments	69.40%	44.50%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	81.00%	46.00%
Defined Benefit Plan, Debt Security | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	48.00%	46.50%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	48.00%	45.00%
Real Estate Funds | United States
Defined Benefit Plan Disclosure
Total investments	19.00%	14.80%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	8.00%	16.00%
Real Estate Funds | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	3.00%	9.00%
Real Estate Funds | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	13.00%	23.00%
Real Estate Funds | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4.40%	4.80%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%	6.00%
Real Estate Funds | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	2.00%	2.00%
Real Estate Funds | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	8.00%	8.00%
Other Investments [Member] | United States
Defined Benefit Plan Disclosure
Total investments	0.80%	2.10%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1.00%	1.00%
Other Investments [Member] | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	0.00%
Other Investments [Member] | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%	5.00%
Other Investments [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	3.50%	5.20%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	3.00%	3.00%
Other Investments [Member] | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	3.00%	3.00%
Other Investments [Member] | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	13.00%	12.00%
Insurance product | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4.90%	5.40%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%	5.00%
Insurance product | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%	5.00%
Insurance product | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%	5.00%

EMPLOYEE BENEFIT PLANS Fair val

EMPLOYEE BENEFIT PLANS Fair value plan assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 752,512		$ 721,005		$ 103,385
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	100.00%		100.00%
Defined Benefit Plan, Plan Assets, Amount	$ 381,781		$ 365,718		103,385
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100.00%		100.00%
United States
Defined Benefit Plan Disclosure
Total investments	100.00%		100.00%
Defined Benefit Plan, Plan Assets, Amount	$ 370,731		$ 355,287		$ 0
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100.00%		100.00%
Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 4,113		$ 8,049
Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	1,248		747
Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	2,865		7,302
Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	18,781		19,611
Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	18,781		19,611
Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	729,618	[1]	693,345	[2]
Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	361,752	[1]	345,360	[2]
Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	367,866	[1]	347,985	[2]
Other Investments [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 16,335		$ 26,361
Other Investments [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	3.50%		5.20%
Defined Benefit Plan, Plan Assets, Amount	$ 13,470		$ 19,059
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	3.00%		3.00%
Other Investments [Member] | United States
Defined Benefit Plan Disclosure
Total investments	0.80%		2.10%
Defined Benefit Plan, Plan Assets, Amount	$ 2,865		$ 7,302
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1.00%		1.00%
Other Investments [Member] | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 4,113		$ 8,049
Other Investments [Member] | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	1,248		747
Other Investments [Member] | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	2,865		7,302
Other Investments [Member] | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Investments [Member] | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Investments [Member] | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Investments [Member] | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Investments [Member] | Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Investments [Member] | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Investments [Member] | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	12,222	[1]	18,312	[2]
Other Investments [Member] | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	12,222	[1]	18,312	[2]
Other Investments [Member] | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	[1]	0	[2]
Defined Benefit Plan, Equity Securities
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 189,809		$ 276,635
Defined Benefit Plan, Equity Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	39.20%		38.10%
Defined Benefit Plan, Plan Assets, Amount	$ 149,707		$ 139,537
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	39.00%		41.00%
Defined Benefit Plan, Equity Securities | United States
Defined Benefit Plan Disclosure
Total investments	10.80%		38.60%
Defined Benefit Plan, Plan Assets, Amount	$ 40,102		$ 137,098
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	10.00%		37.00%
Defined Benefit Plan, Equity Securities | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
Defined Benefit Plan, Equity Securities | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Defined Benefit Plan, Equity Securities | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	189,809	[1]	276,635	[2]
Defined Benefit Plan, Equity Securities | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	149,707	[1]	139,537	[2]
Defined Benefit Plan, Equity Securities | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	40,102	[1]	137,098	[2]
US Treasury and Government
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 133,672		$ 78,808
US Treasury and Government | United States
Defined Benefit Plan Disclosure
Total investments	36.10%		22.20%
Defined Benefit Plan, Plan Assets, Amount	$ 133,672		$ 78,808
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	34.00%		24.00%
US Treasury and Government | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
US Treasury and Government | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
US Treasury and Government | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
US Treasury and Government | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
US Treasury and Government | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
US Treasury and Government | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
US Treasury and Government | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	133,672	[1]	78,808	[2]
US Treasury and Government | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	133,672	[1]	78,808	[2]
Corporate Debt Securities
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 112,526		$ 45,501
Corporate Debt Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4.50%		5.90%
Defined Benefit Plan, Plan Assets, Amount	$ 17,328		$ 21,677
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0.00%		1.00%
Corporate Debt Securities | United States
Defined Benefit Plan Disclosure
Total investments	25.70%		6.70%
Defined Benefit Plan, Plan Assets, Amount	$ 95,198		$ 23,824
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	40.00%		8.00%
Corporate Debt Securities | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
Corporate Debt Securities | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Corporate Debt Securities | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	112,526	[1]	45,501	[2]
Corporate Debt Securities | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	17,328	[1]	21,677	[2]
Corporate Debt Securities | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	95,198	[1]	23,824	[2]
Other Debt Obligations
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 194,109		$ 204,016
Other Debt Obligations | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	43.50%		40.60%
Defined Benefit Plan, Plan Assets, Amount	$ 165,863		$ 148,469
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	48.00%		44.00%
Other Debt Obligations | United States
Defined Benefit Plan Disclosure
Total investments	7.60%		15.60%
Defined Benefit Plan, Plan Assets, Amount	$ 28,246		$ 55,547
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	7.00%		14.00%
Other Debt Obligations | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
Other Debt Obligations | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Other Debt Obligations | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	194,109	[1]	204,016	[2]
Other Debt Obligations | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	165,863	[1]	148,469	[2]
Other Debt Obligations | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	28,246	[1]	55,547	[2]
Real Estate Funds
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 87,280		$ 70,073
Real Estate Funds | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4.40%		4.80%
Defined Benefit Plan, Plan Assets, Amount	$ 16,632		$ 17,365
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%		6.00%
Real Estate Funds | United States
Defined Benefit Plan Disclosure
Total investments	19.00%		14.80%
Defined Benefit Plan, Plan Assets, Amount	$ 70,648		$ 52,708
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	8.00%		16.00%
Real Estate Funds | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
Real Estate Funds | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Real Estate Funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	87,280	[1]	70,073	[2]
Real Estate Funds | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	16,632	[1]	17,365	[2]
Real Estate Funds | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	70,648	[1]	52,708	[2]
Insurance product
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 18,781		$ 19,611
Insurance product | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4.90%		5.40%
Defined Benefit Plan, Plan Assets, Amount	$ 18,781		$ 19,611
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	5.00%		5.00%
Insurance product | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
Insurance product | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Insurance product | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	18,781		19,611
Insurance product | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	18,781		19,611
Insurance product | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Insurance product | Level 3 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0		0
Insurance product | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	[1]	0	[2]
Insurance product | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0	[1]	$ 0	[2]
[1]	Investments measured at fair value using the NAV per share practical expedient have not been classified in the fair value hierarchy. The amounts presented in the tables above are intended to reconcile the fair value hierarchy to the total fair value of plan assets.
[2]	Investments measured at fair value using the NAV per share practical expedient have not been classified in the fair value hierarchy. The amounts presented in the tables above are intended to reconcile the fair value hierarchy to the total fair value of plan assets.

EMPLOYEE BENEFIT PLANS - Other

EMPLOYEE BENEFIT PLANS - Other Benefits (Details) - Phantom Share Units (PSUs) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure
Other Deferred Compensation Arrangements, Liability, Classified, Noncurrent	$ 22,700	$ 22,800
Share-based Payment Arrangement, Expense	13,600	9,200
Deferred Compensation Cash-based Arrangements, Liability, Current	10,900	6,500
Deferred Compensation Cash-based Arrangements, Liability, Current and Noncurrent	17,300	11,700
Deferred Compensation Cash-based Arrangements, Liability, Classified, Noncurrent	$ 6,400	$ 5,200
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years

STOCK-BASED COMPENSATION (Detai

STOCK-BASED COMPENSATION (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase to Number of Shares Authorized to be Issued				2,150,000
Stock-based compensation expense				$ 30,821	$ 19,279	$ 19,062
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value				$ 69,700	8,800	10,700
Common Stock, Capital Shares Reserved for Future Issuance				2,138,865
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized				$ 45,100
Share-based Payment Arrangement, Expense, Tax Benefit				$ 16,800	$ 2,000	$ 2,500
Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				30.00%
Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				30.00%
Share-based Payment Arrangement, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				40.00%
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 33.19	$ 13.86	$ 16.36
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number				974,162	921,495	363,729	327,798
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 77.81	$ 37.44	$ 54.13
Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 30,800	$ 19,300	$ 19,100
Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,700	$ 17,000	$ 26,400

STOCK-BASED COMPENSATION - SCHE

STOCK-BASED COMPENSATION - SCHEDULE OF SHARE-BASED COMPENSATION, STOCK OPTIONS AND STOCK APPRECIATION RIGHTS AWARD ACTIVITY (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangements By Share Based Payment Award, Options and Stock Appreciation Rights Outstanding [Roll Forward]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 60.70	$ 47.11	$ 35.01
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	380,819	305,269	195,305	138,896
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 76.76	$ 49.56	$ 54.64
Share Based Compensation Arrangements By Share Based Payment Award, Options and Stock Appreciation Rights Outstanding [Roll Forward]
Stock-settled appreciation rights granted	122,812	158,756	126,874
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 33.19	$ 13.86	$ 16.36
Share Based Compensation Arrangements By Share Based Payment Award, Options and Stock Appreciation Rights Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Exercised	916,906	391,339	113,099
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures	13,854	46,245	115,103
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 54.42	$ 65.93	$ 65.27
Weighted Average Remaining Contractual Term, Outstanding	6 years 1 month 6 days
Weighted Average Remaining Contractual Term, Exercisable	5 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 95,246
Aggregate Intrinsic Value, Exercisable	$ 68,920
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	1,001,708	1,630,891	1,723,370
Stock-settled appreciation rights granted	139,592	262,091	213,618
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 62.79	$ 62.72	$ 59
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 62.09	$ 60.48	$ 59.72	$ 59.26
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	1,370,388	2,161,556	2,337,049	2,351,633
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 77.05	$ 48.32	$ 54.63

STOCK-BASED COMPENSATION - SUMM

STOCK-BASED COMPENSATION - SUMMARY OF RESTRICTED STOCK UNITS AND PERFORMANCE-BASED AWARDS (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Shares	380,819	305,269	195,305	138,896
Granted	122,812	158,756	126,874
Vested in Period	(22,371)	(25,909)	(25,696)
Unvested, Weighted Average Fair Value	$ 59.23	$ 52.61	$ 60.24	$ 59.33
Granted, Weighted Average Fair Value	76.76	49.56	54.64
Vested in Period, Weighted Average Fair Value	$ 62.80	$ 78.04	$ 42.44
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(24,891)	(22,883)	(44,769)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 61.26	$ 69.39	$ 52.11
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Shares	974,162	921,495	363,729	327,798
Granted	314,480	656,717	192,106
Vested in Period	(232,152)	(83,253)	(136,777)
Unvested, Weighted Average Fair Value	$ 53.48	$ 43.15	$ 60	$ 57.87
Granted, Weighted Average Fair Value	77.81	37.44	54.13
Vested in Period, Weighted Average Fair Value	$ 44.10	$ 69.17	$ 46.52
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(29,661)	(15,698)	(19,398)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 63.86	$ 56.79	$ 59.62

STOCK-BASED COMPENSATION - SC_2

STOCK-BASED COMPENSATION - SCHEDULE OF SHARE-BASED PAYMENT AWARDS, VALUATION ASSUMPTIONS (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	0.80%	1.40%	2.50%
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-settled appreciation rights granted	139,592	262,091	213,618
Expected life (in years)	7 years	5 years	5 years
Expected volatility	41.00%	30.00%	29.00%

STOCK-BASED COMPENSATION - SC_3

STOCK-BASED COMPENSATION - SCHEDULE OF SHARE-BASED PAYMENT AWARD, PERFORMANCE-BASED AWARDS, VALUATION ASSUMPTIONS (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.80%	1.40%	2.50%

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	Dec. 31, 2021USD ($)
Other Commitments [Line Items]
Letters of Credit Outstanding, Amount	$ 50.1

BUSINESS SEGMENTS (Details)

BUSINESS SEGMENTS (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2021USD ($)Employeessegmentcountries		Dec. 31, 2020USD ($)		Dec. 31, 2019USD ($)
Segment Reporting [Abstract]
Net sales	[1]	$ 18,217,512		$ 12,325,995		$ 8,358,917
Operating Income (Loss)		801,873		347,038		346,217
Segment Reporting Information [Line Items]
Net sales	[1]	18,217,512		12,325,995		8,358,917
Operating Income (Loss)		801,873		347,038		346,217
Adjusted EBITDA		$ 1,175,683		$ 660,317		$ 430,516
Adjusted EBITDA Margin Percentage		6.50%		5.40%		5.20%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		$ 36,600
Depreciation and amortization		198,554		$ 121,600		$ 62,107
Other, net		(48,112)		(2,395)		(1,554)
Stock-based compensation expense (EBITDA)		25,699	[2]	16,714	[3]	19,062
Stock-based compensation expense		30,821		19,279		19,062
Business Combination, Integration Related Costs		158,484		132,236		3,130
Merger-related Inventory Fair Value Adjustments				43,693
Segment Reporting Information Out-of-period Adjustment				18,852
Gain (Loss) on Disposition of Assets				(19,816)
Gain (Loss) on Disposition of Business		(8,927)		(19,816)		0
Payments for (Proceeds from) Productive Assets		54,746		56,671		44,067
Net Income (Loss) Available to Common Stockholders, Basic		407,974		70,421		223,426
Net loss attributable to noncontrolling interest		1,020		(521)		(1,228)
Preferred Stock Dividends, Income Statement Impact		57,408		30,139		0
Income Tax Expense (Benefit)		115,510		22,803		59,863
Interest expense, net		268,073		226,591		65,710
Segment Reporting, Asset Reconciling Item [Line Items]
Assets		$ 12,617,699		11,880,214
Number of Reportable Segments | segment		3
EES
Segment Reporting [Abstract]
Net sales		$ 7,621,263		5,479,760		4,860,541
Operating Income (Loss)		542,059		260,207		261,788
Segment Reporting Information [Line Items]
Net sales		7,621,263		5,479,760		4,860,541
Operating Income (Loss)		542,059		260,207		261,788
Adjusted EBITDA		$ 604,461		$ 308,327		$ 291,473
Adjusted EBITDA Margin Percentage		7.90%		5.60%		6.00%
Depreciation and amortization		$ 55,998		$ 35,811		$ 28,569
Other, net		1,872		1,780		1,554
Stock-based compensation expense (EBITDA)		6,404		4,080	[4]	1,116
Business Combination, Integration Related Costs		0		0		0
Merger-related Inventory Fair Value Adjustments				15,411
Segment Reporting Information Out-of-period Adjustment				12,634
Gain (Loss) on Disposition of Assets				(19,816)
Gain (Loss) on Disposition of Business		0
Payments for (Proceeds from) Productive Assets		4,469		7,081		20,405
Net Income (Loss) Available to Common Stockholders, Basic		543,633		262,829		264,570
Net loss attributable to noncontrolling interest		298		(842)		(1,228)
Preferred Stock Dividends, Income Statement Impact		0		0
Income Tax Expense (Benefit)		$ 0		0		0
Entity Number of Employees | Employees		6,400
Additional countries (in countries) | countries		50
Interest expense, net		$ 0		0		0
Segment Reporting, Asset Reconciling Item [Line Items]
Assets		4,098,335		3,726,855
CSS
Segment Reporting [Abstract]
Net sales		5,715,238		3,323,264		909,496
Operating Income (Loss)		395,343		217,163		43,835
Segment Reporting Information [Line Items]
Net sales		5,715,238		3,323,264		909,496
Operating Income (Loss)		395,343		217,163		43,835
Adjusted EBITDA		$ 480,820		$ 280,656		$ 51,067
Adjusted EBITDA Margin Percentage		8.40%		8.40%		5.60%
Depreciation and amortization		$ 82,870		$ 37,765		$ 7,155
Other, net		(1,312)		48		0
Stock-based compensation expense (EBITDA)		2,607		1,403	[4]	77
Business Combination, Integration Related Costs		0		0		0
Merger-related Inventory Fair Value Adjustments				22,000
Segment Reporting Information Out-of-period Adjustment				2,325
Gain (Loss) on Disposition of Assets				0
Gain (Loss) on Disposition of Business		0
Payments for (Proceeds from) Productive Assets		3,197		1,495		3,093
Net Income (Loss) Available to Common Stockholders, Basic		394,031		217,211		43,835
Net loss attributable to noncontrolling interest		0		0		0
Preferred Stock Dividends, Income Statement Impact		0		0
Income Tax Expense (Benefit)		$ 0		0		0
Entity Number of Employees | Employees		3,300
Additional countries (in countries) | countries		50
Interest expense, net		$ 0		0		0
Segment Reporting, Asset Reconciling Item [Line Items]
Assets		4,601,132		4,275,611
UBS
Segment Reporting [Abstract]
Net sales		4,881,011		3,522,971		2,588,880
Operating Income (Loss)		412,740		231,702		184,931
Segment Reporting Information [Line Items]
Net sales		4,881,011		3,522,971		2,588,880
Operating Income (Loss)		412,740		231,702		184,931
Adjusted EBITDA		$ 428,367		$ 265,593		$ 198,745
Adjusted EBITDA Margin Percentage		8.80%		7.50%		7.70%
Depreciation and amortization		$ 22,447		$ 22,380		$ 13,583
Other, net		(42)		(24)		0
Stock-based compensation expense (EBITDA)		2,107		1,336	[4]	231
Business Combination, Integration Related Costs		0		0		0
Merger-related Inventory Fair Value Adjustments				6,282
Segment Reporting Information Out-of-period Adjustment				3,893
Gain (Loss) on Disposition of Assets				0
Gain (Loss) on Disposition of Business		8,927
Payments for (Proceeds from) Productive Assets		5,207		12,834		6,460
Net Income (Loss) Available to Common Stockholders, Basic		412,698		231,678		184,931
Net loss attributable to noncontrolling interest		0		0		0
Preferred Stock Dividends, Income Statement Impact		0		0
Income Tax Expense (Benefit)		$ 0		0		0
Entity Number of Employees | Employees		2,400
Interest expense, net		$ 0		0		0
Segment Reporting, Asset Reconciling Item [Line Items]
Assets		3,266,231		2,947,406
Corporate Segment
Segment Reporting [Abstract]
Net sales		0		0		0
Operating Income (Loss)		(548,269)		(362,034)		(144,337)
Segment Reporting Information [Line Items]
Net sales		0		0		0
Operating Income (Loss)		(548,269)		(362,034)		(144,337)
Adjusted EBITDA		(337,965)		(194,259)		(110,769)
Merger-related Stock-based compensation expense		(5,100)		(2,600)
Depreciation and amortization		37,239		25,644		12,800
Other, net		47,594	[5]	591		0
Stock-based compensation expense (EBITDA)		14,581		9,895	[4]	17,638
Business Combination, Integration Related Costs		158,484		132,236		3,130
Merger-related Inventory Fair Value Adjustments				0
Segment Reporting Information Out-of-period Adjustment				0
Gain (Loss) on Disposition of Assets				0
Gain (Loss) on Disposition of Business		0
Payments for (Proceeds from) Productive Assets		41,873		35,261		14,109
Net Income (Loss) Available to Common Stockholders, Basic		(942,388)		(641,297)		(269,910)
Net loss attributable to noncontrolling interest		722		321		0
Preferred Stock Dividends, Income Statement Impact		57,408		30,139
Income Tax Expense (Benefit)		115,510		22,803		59,863
Interest expense, net		(268,073)		(226,591)		$ (65,710)
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	[6]	$ 652,001		$ 930,342
[1]	(2) Wesco attributes revenues from external customers to individual countries on the basis of point of sale.
[2]	(2) Stock-based compensation expense in the calculation of adjusted EBITDA for the year ended December 31, 2021 excludes $5.1 million as such amount is included in merger-related and integration costs.
[3]	(4) Stock-based compensation expense in the calculation of adjusted EBITDA for the year ended December 31, 2020 excludes $2.6 million as such amount is included in merger-related and integration costs.
[4]	(3) Stock-based compensation and the out-of-period adjustment by reportable segment for the year ended December 31, 2020, as previously reported in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020, have been reallocated to conform to the current period's presentation.
[5]	(1) Corporate other non-operating income in the calculation of adjusted EBITDA for the year ended December 31, 2021 includes a $36.6 million curtailment gain resulting from the remeasurement of the Company's pension obligations in the U.S. and Canada due to amending certain terms of such defined benefit plans.
[6]	Total assets for Corporate primarily consist of cash and cash equivalents, deferred income taxes, fixed assets and right-of-use assets associated with operating leases.

SEGMENTS AND RELATED INFORMATIO

SEGMENTS AND RELATED INFORMATION - SCHEDULE OF REVENUE FROM EXTERNAL CUSTOMERS AND LONG LIVED ASSETS, BY GEOGRAPHICAL AREAS (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets		$ 909,875	$ 933,862
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets		698,942	693,807
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets		141,380	146,620
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	[1]	$ 69,553	$ 93,435
[1]	No individual other international country's tangible long-lived assets are material.The following tables reconcile net income attributable to common stockholders to adjusted EBITDA and adjusted EBITDA margin % by segment, which are non-GAAP financial measures, for the periods presented:

Schedule II - Valuation and Q_3

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Anixter International [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Charged to Other Accounts		$ 59,300
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount		41,722		$ 23,909		$ 25,443		$ 24,468
Valuation Allowances and Reserves, Charged to Cost and Expense		12,944		11,701		7,006
Valuation Allowances and Reserves, Charged to Other Accounts		13,669	[1]	5,160	[1]	52
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[2]	(8,800)		(18,395)		(6,083)
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount		46,269		60,629		5,854	$ 4,072
Valuation Allowances and Reserves, Charged to Cost and Expense		1,115		1,900		1,745
Valuation Allowances and Reserves, Charged to Other Accounts		1,791		52,875	[3]	37
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction		$ (17,266)		$ 0		$ 0
[1]	For the years ended December 31, 2021 and 2020, the amount charged to other accounts primarily relates to the acquisition of Anixter.
[2]	Includes a reduction in the allowance for expected credit losses due to the write-off of trade accounts receivable.
[3]	For the year ended December 31, 2020, the amount charged to other accounts includes $59.3 million that was recorded in connection with the acquisition of Anixter. (2) For the year ended December 31, 2021, deductions primarily include a decrease in the valuation allowance recorded against deferred tax assets related to foreign tax credit carryforwards.