WESCO International (WCC) 10-K 20 Feb 24 2023 FY Annual report Financial data

COVER PAGE

COVER PAGE - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2023	Feb. 16, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
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, Address Line One	225 West Station Square Drive
Entity Address, Address Line Two	Suite 700
Entity Address, Postal Zip Code	15219
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			$ 9.1
Entity Common Stock, Shares Outstanding		50,953,600
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 2024 Annual Meeting of Stockholders.
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Financial Statement Error Correction [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 1/1,000th 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, 2023
Auditor [Line Items]
Auditor Location	Pittsburgh, Pennsylvania
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 524.1	$ 527.3
Trade accounts receivable	3,639.5	3,662.7
Other accounts receivable	430.5	435.7
Inventories	3,572.1	3,498.8
Prepaid expenses and other current assets	225.4	206
Total current assets	8,391.6	8,330.5
Property, buildings and equipment, net	423.6	402.7
Operating Lease, Right-of-Use Asset	761.2	625.1
Intangible assets, net	1,857.6	1,943.4
Goodwill	3,262.3	3,240.9
Deferred Income Taxes	42.3	34.2
Other assets	322.3	234.9
Total assets	15,060.9	14,811.7
Current Liabilities:
Accounts payable	2,431.5	2,728.2
Accrued payroll and benefit costs	191.7	269.1
Short-term debt and current portion of long-term debt	8.6	70.5
Other current liabilities	756.6	749.6
Total current liabilities	3,388.4	3,817.3
Long-term Debt, Excluding Current Maturities	5,313.1	5,346
Operating Lease, Liability, Noncurrent	641.7	510.4
Deferred Income Tax Liabilities, Net	451.9	460.7
Other noncurrent liabilities	233.9	227.6
Total liabilities	10,029	10,362.1
Commitments and contingencies
Stockholders' Equity:
Additional capital	2,037.1	2,005.4
Retained earnings	4,391.7	3,795
Treasury stock, at cost	(1,060.4)	(969.2)
Accumulated other comprehensive income (loss)	(332)	(377.8)
Total stockholders' equity	5,037.1	4,454.2
Noncontrolling interest	(5.2)	(4.7)
Total WESCO International stockholders' equity	5,031.9	4,449.6
Total liabilities and stockholders' equity	15,060.9	14,811.7
Common Stock
Stockholders' Equity:
Common Stock	0.7	0.7
Common Class B
Stockholders' Equity:
Common Stock	0	0
Preferred Stock
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	0	0
Series A Preferred Stock
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	$ 0	$ 0

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Net sales	$ 22,385,200	$ 21,420,100	$ 18,217,500
Cost of goods sold (excluding depreciation and amortization below)	17,541,500	16,758,800	14,425,400
Selling, general and administrative expense	3,256,000	3,044,200	2,791,600
Depreciation and amortization	181,300	179,000	198,600
Income from operations	1,406,400	1,438,100	801,900
Interest expense, net	389,300	294,400	268,100
Other, net	25,100	7,000	(48,100)
Income before income taxes	992,000	1,136,700	581,900
Provision for income taxes	225,900	274,500	115,500
Net income	766,100	862,100	466,400
Net loss attributable to noncontrolling interest	600	1,700	1,000
Net Income attributable to WESCO International, Inc.	765,500	860,500	465,400
Preferred Stock Dividends, Income Statement Impact	57,400	57,400	57,400
Net Income (Loss) Available to Common Stockholders, Basic	708,100	803,100	408,000
Comprehensive Income:
Foreign currency translation adjustment	57,100	(127,000)	(15,600)
Benefit plan adjustments, net of tax	(11,300)	(14,700)	42,700
Comprehensive income attributable to WESCO International, Inc.	$ 753,900	$ 661,300	$ 435,100
Earnings per share :
Basic	$ 13.86	$ 15.83	$ 8.11
Diluted	$ 13.54	$ 15.33	$ 7.84

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Total	Common Class B	Common Stock	Common Stock Common Class B	Preferred Stock	Additional Capital	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest	Treasury Stock, Common [Member]
Common stock, shares issued			67,596,515	4,339,431
Preferred stock, shares issued					21,612
Treasury Stock, Common, Shares										21,870,961
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 3,336,500,000		$ 700,000	$ 0	$ 0	$ 1,942,800,000	$ 2,601,700,000	$ (263,100,000)	$ (7,300,000)	$ (938,300,000)
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	17,900,000		$ 0							$ (17,900,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			662,261							155,961
APIC, Share-based Payment Arrangement, Recognition and Exercise						0
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture	30,800,000					30,800,000
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(9,200,000)		$ 0			4,300,000	4,900,000
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			96,479
Net Income attributable to WESCO International, Inc.	465,400,000						465,400,000
Dividends, Preferred Stock	(57,400,000)						(57,400,000)
Translation adjustment	(15,600,000)							(15,600,000)
Benefit plan adjustments, tax	13,000,000
Benefit plan adjustments, net of tax	42,700,000							42,700,000
Net loss attributable to noncontrolling interest	1,000,000								1,000,000
Common stock, shares issued			68,162,297	4,339,431
Preferred stock, shares issued					21,612
Treasury Stock, Common, Shares										22,026,922
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	3,776,200,000		$ 700,000	$ 0	$ 0	1,969,300,000	3,004,700,000	(236,000,000)	(6,300,000)	$ (956,200,000)
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	1,900,000		$ 0							$ (1,900,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			569,112							1,229
APIC, Share-based Payment Arrangement, Recognition and Exercise						0
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture	46,400,000					46,400,000
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(23,000,000)		$ 0			10,100,000	12,900,000
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			195,705
Net Income attributable to WESCO International, Inc.	860,500,000						860,500,000
Dividends, Preferred Stock	(57,400,000)						(57,400,000)
Stockholders' Equity, Other						(200,000)	100,000			$ 0
Translation adjustment	(127,100,000)							(127,000,000)
Benefit plan adjustments, tax	(3,400,000)
Benefit plan adjustments, net of tax	(14,700,000)							(14,700,000)
Net loss attributable to noncontrolling interest	1,700,000								1,700,000
Treasury Stock, Value, Acquired, Cost Method	(11,100,000)									$ (11,100,000)
Treasury Stock, Shares, Acquired										(87,502)
Common Stock		$ 0
Common stock, shares issued		4,339,431	68,535,704	4,339,431
Preferred stock, shares issued					21,612
Additional capital	2,005,400,000
Retained earnings	3,795,000,000
Treasury stock, at cost	(969,200,000)
Noncontrolling interest	(4,700,000)
Accumulated other comprehensive income (loss)	$ (377,800,000)
Treasury Stock, Common, Shares	22,115,653									22,115,653
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 4,449,600,000		$ 700,000	$ 0	$ 0	2,005,400,000	3,795,000,000	(377,800,000)	(4,700,000)	$ (969,200,000)
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	15,800,000		$ 0							$ (16,200,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			1,054,608							100,998
APIC, Share-based Payment Arrangement, Recognition and Exercise						400,000
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture	48,100,000					48,100,000
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(52,000,000)		$ 0			16,900,000	35,100,000
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			311,635
Net Income attributable to WESCO International, Inc.	765,500,000						765,500,000
Dividends, Preferred Stock	(57,400,000)						(57,400,000)
Stockholders' Equity, Other						100,000	300,000
Translation adjustment	57,500,000							57,100,000
Benefit plan adjustments, tax	(7,400,000)
Benefit plan adjustments, net of tax	(11,300,000)							(11,300,000)
Net loss attributable to noncontrolling interest	600,000								600,000
Treasury Stock, Value, Acquired, Cost Method	(75,000,000)									$ (75,000,000)
Treasury Stock, Shares, Acquired										(504,335)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(1,100,000)								(1,100,000)
Dividends, Common Stock	(76,600,000)						(76,600,000)
Common Stock		$ 0
Common stock, shares issued		4,339,431	69,278,677	4,339,431
Preferred stock, shares issued					21,612
Additional capital	2,037,100,000
Retained earnings	4,391,700,000
Treasury stock, at cost	(1,060,400,000)
Noncontrolling interest	(5,200,000)
Accumulated other comprehensive income (loss)	$ (332,000,000)
Treasury Stock, Common, Shares	22,720,986									22,720,986
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 5,031,900,000		$ 700,000	$ 0	$ 0	$ 2,037,100,000	$ 4,391,700,000	$ (332,000,000)	$ (5,200,000)	$ (1,060,400,000)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parentheticals) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stockholders' Equity Parenthetical [Abstract]
Benefit plan adjustments, tax	$ (7,400,000)	$ (3,400,000)	$ 13,000,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net income	$ 766,100	$ 862,100	$ 466,400
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	181,300	179,000	198,600
Stock-based compensation expense	48,100	46,400	30,800
Amortization of Debt Issuance Costs and Discounts	14,800	15,200	19,200
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	0	0	(36,600)
Gain (Loss) on Disposition of Business	0	0	(8,900)
Other operating activities, net	(500)	3,700	7,400
Deferred income taxes	(7,900)	(1,200)	(78,300)
Changes in assets and liabilities
Increase (Decrease) in Accounts Receivable	52,200	(690,600)	(531,800)
Increase (Decrease) in Accounts and Other Receivables	3,600	(54,800)	(136,700)
Inventories	(68,400)	(817,000)	(530,700)
Increase (Decrease) in Other Operating Assets	(60,600)	(153,200)	(56,300)
Accounts payable	319,700	(552,900)	(449,600)
Accrued payroll and benefit costs	(92,300)	(63,100)	84,200
Other current and noncurrent liabilities	(23,500)	131,600	190,300
Net cash provided by operating activities	493,200	11,000	67,100
Investing Activities:
Capital expenditures	(92,300)	(99,400)	(54,700)
Acquisition payments, net of cash acquired	0	(186,800)	0
Proceeds from Divestiture of Businesses, Net of Cash Divested	0	0	56,000
Proceeds from sale of assets	600	200	5,200
Other investing activities, net	2,100	2,400	(3,900)
Net cash used in investing activities	(89,600)	(283,600)	2,500
Financing Activities:
Proceeds from Short-Term Debt	17,100	19,500	14,500
Repayments of Short-Term Debt	(22,700)	(19,500)	(34,800)
Proceeds from issuance of long-term debt	3,290,200	4,470,000	3,231,400
Repayments of Long-term Debt	(3,346,000)	(3,772,300)	(2,565,100)
Payment, Tax Withholding, Share-based Payment Arrangement	(68,300)	(25,800)	(27,200)
Payments for Repurchase of Common Stock	(75,000)	(11,100)	0
Payments of Ordinary Dividends, Common Stock	(76,600)	0	0
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	(57,400)	(57,400)	(57,400)
Payments of Ordinary Dividends, Noncontrolling Interest	(1,100)	0	0
Other financing activities, net	5,500	19,500	17,500
Net cash provided (used) by financing activities	(403,900)	584,000	(310,800)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	(2,900)	3,300	4,600
Net change in cash and cash equivalents	(3,200)	314,800	(236,600)
Cash and cash equivalents at the beginning of period	527,300	212,600	449,100
Cash and cash equivalents at the end of period	524,100	527,300	212,600
Supplemental disclosures:
Cash paid for interest	386,800	272,400	249,700
Cash paid for taxes	207,900	292,900	118,200
Repayment of 5.375% Senior Notes due 2021
Financing Activities:
Repayments of Senior Debt	0	0	500,000
Repayment of 5.375% Senior Notes due 2024
Financing Activities:
Repayments of Senior Debt	$ 0	$ 0	$ 354,700

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
5.50% Senior Notes due 2023 [Member]
Repayments of Senior Debt	$ (58.6)	$ 0	$ 0

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss	$ 55.9	$ 46.5
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ 43	$ 57.9
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	20,000,000
Treasury Stock, Common, Shares	22,720,986	22,115,653
Preferred Stock
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares outstanding	0	0
Series A Preferred Stock
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	25,000
Preferred stock, shares issued	21,612
Common Stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	210,000,000	210,000,000
Common stock, shares issued	69,278,677	68,535,704
Common stock, shares outstanding	50,897,122	50,759,482
Common Class B
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

ORGANIZATION

ORGANIZATION	12 Months Ended
	Dec. 31, 2023
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.

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2023
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. In the first quarter of the fiscal year ended December 31, 2023, we changed our presentation in tables from thousands to millions. Certain amounts as of December 31, 2023 and 2022 and for the years ended December 31, 2023, 2022 and 2021 in the consolidated financial statements and associated notes may not foot or recalculate due to rounding. Reclassifications The Consolidated Statements of Cash Flows and the reconciliation between the federal statutory income tax rate and the effective tax rate in Note 11, “Income Taxes” for the years ended December 31, 2022 and 2021, 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 or the effective tax rates 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 generally 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 $233.1 million at December 31, 2023 and $246.2 million at December 31, 2022. Supplier volume rebate income as a percentage of net sales was 1.4% in 2023, 1.6% in 2022 and 1.4% in 2021. Supplier Finance Programs The Company has supplier finance programs that are administered by intermediaries. Under these arrangements, participating suppliers may elect to receive early payment of invoices that have been confirmed by the Company, less an interest deduction or fees paid by the supplier, which is paid to the supplier by third-party finance providers. Wesco agrees to pay the stated amount of confirmed invoices in full on the original due date of the invoices, which is typically within 45 to 180 days of the invoice date, regardless of whether the supplier elects to receive early payment from the third-party finance providers. The Company does not provide assets pledged as security or other forms of guarantees to the finance providers or intermediaries under these arrangements. As of December 31, 2023 and 2022, the amounts due to suppliers that participate in the Company's supplier finance programs were approximately $ 32.6 million 30.7 million Cash and Cash Equivalents Cash equivalents are defined as highly liquid investments with original maturities of 90 days or less when purchased. Cash and cash equivalents in the Consolidated Balance Sheets include $21.9 million and $21.2 million as of December 31, 2023 and 2022, respectively, that is restricted from use to fund operations. 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 $55.9 million at December 31, 2023 and $46.5 million at December 31, 2022. The total amount recorded as selling, general and administrative expense related to credit losses was $18.6 million, $18.0 million and $12.9 million for 2023, 2022 and 2021, respectively. Inventories Inventories primarily consist of merchandise purchased for resale and are stated at the lower of cost or 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. The carrying value of inventories reflect reductions for excess and obsolescence of $113.4 million and $70.0 million at December 31, 2023 and 2022, respectively. The total expense related to excess and obsolete inventories, which is included in cost of goods sold, was $63.1 million, $43.2 million and $37.1 million for 2023, 2022 and 2021, 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 three to eight 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 $423.6 million net book value of property, buildings and equipment as of December 31, 2023, $152.8 million consists of land, buildings and leasehold improvements that are geographically dispersed among Wesco’s nearly 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, among others, 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 has elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of twelve 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 on a secured basis 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 as of October 1, 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 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, 2023 and 2022, goodwill and indefinite-lived trademarks totaled $4.1 billion and $4.0 billion, respectively. The determination of fair value involves significant management judgment, particularly as it relates to the underlying assumptions and factors around future 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 5 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. Cloud Computing Arrangements 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 $195.4 million and $104.1 million as of December 31, 2023 and 2022, respectively, and the related accumulated amortization was $15.5 million and $6.1 million, respectively. 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 $28.1 million and $28.0 million at December 31, 2023 and 2022, 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 consistent with amounts 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 functional currency for most of the Company's operations outside the U.S. is generally the applicable local currency. 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. The Company may re-evaluate the functional currencies of certain operations outside the U.S. if there are significant changes to operations that indicate that a change in functional currency may be necessary. Defined Benefit Pension Plans 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 expense (income), 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 expense (income), net”) primarily includes the non-service cost components of net periodic pension cost (benefit) and foreign exchange gains and losses. Recently Adopted and Recently Issued Accounting Standards In September 2022, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2022-04, Supplier Finance Programs (Subtopic 405-50): Disclosure of Supplier Finance Program Obligations , which requires that a buyer in a supplier finance program disclose sufficient information about the program to allow a user of financial statements to understand the program's nature, activity during the period, changes from period to period, and potential magnitude. The amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, except for the amendment on rollforward information, which is effective for fiscal years beginning after December 15, 2023. The Company adopted this ASU in the first quarter of 2023, except for the amendment on rollforward information, which the Company will begin disclosing in its Annual Report on Form 10-K for the fiscal year ending December 31, 2024. The adoption of this ASU resulted in additional disclosure of the Company's supplier finance programs. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances prior reportable segment disclosure requirements in part by requiring entities to disclose significant expenses related to their reportable segments. The amendments in this ASU are effective on a retrospective basis for annual periods beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. Management is currently evaluating the impact that this accounting standard will have on its consolidated financial statements and notes thereto. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this ASU are effective for annual periods beginning after December 15, 2024 on a prospective basis. Management is currently evaluating the impact that this accounting standard will have on its 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.
Reclassifications	Reclassifications The Consolidated Statements of Cash Flows and the reconciliation between the federal statutory income tax rate and the effective tax rate in Note 11, “Income Taxes” for the years ended December 31, 2022 and 2021, 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 or the effective tax rates for those years.
Supplier Finance Program	Supplier Finance Programs The Company has supplier finance programs that are administered by intermediaries. Under these arrangements, participating suppliers may elect to receive early payment of invoices that have been confirmed by the Company, less an interest deduction or fees paid by the supplier, which is paid to the supplier by third-party finance providers. Wesco agrees to pay the stated amount of confirmed invoices in full on the original due date of the invoices, which is typically within 45 to 180 days of the invoice date, regardless of whether the supplier elects to receive early payment from the third-party finance providers. The Company does not provide assets pledged as security or other forms of guarantees to the finance providers or intermediaries under these arrangements. As of December 31, 2023 and 2022, the amounts due to suppliers that participate in the Company's supplier finance programs were approximately $ 32.6 million 30.7 million

REVENUE

REVENUE	12 Months Ended
	Dec. 31, 2023
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 countries. The following tables disaggregate Wesco’s net sales by segment and geography for the periods presented: Year Ended December 31, (In millions) 2023 2022 2021 Electrical & Electronic Solutions $ 8,610.3 $ 8,823.3 $ 7,621.3 Communications & Security Solutions 7,152.2 6,401.5 5,715.2 Utility & Broadband Solutions 6,622.7 6,195.3 4,881.0 Total by segment $ 22,385.2 $ 21,420.1 $ 18,217.5 Year Ended December 31, (In millions) 2023 2022 2021 United States $ 16,609.1 $ 15,857.3 $ 13,157.9 Canada 2,968.2 3,021.4 2,747.2 Other International (1) 2,807.9 2,541.4 2,312.5 Total by geography (2) $ 22,385.2 $ 21,420.1 $ 18,217.5 (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, 2023 and 2022, $111.9 million and $99.6 million, respectively, of deferred revenue was recorded as a component of other current liabilities in the Consolidated Balance Sheets. The Company recognized $74.0 million of revenue during 2023 that was included in the deferred revenue balance as of December 31, 2022. The amount of revenue recognized during 2022 and 2021 that was deferred as of December 31, 2021 and 2020, respectively, was not material. 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, 2023 and 2022, the Company had contract assets of $35.4 million and $27.5 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 as necessary. Variable consideration reduced revenue for the years ended December 31, 2023, 2022 and 2021 by approximately $427.8 million, $417.1 million and $360.6 million, respectively. As of December 31, 2023 and 2022, the Company's estimated product return obligation was $41.3 million and $46.5 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 $306.8 million, $302.3 million and $248.3 million for the years ended December 31, 2023, 2022 and 2021, respectively.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2023
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 13, “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 $2,823.7 million and $2,881.2 million as of December 31, 2023 and 2022, respectively. The estimated fair value of this debt was $2,880.3 million and $2,929.5 million as of December 31, 2023 and 2022, 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, 2023 and 2022. The Company purchases foreign currency forward contracts to reduce the effect of fluctuations in 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 reduce the effect of fluctuations in 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.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	5. GOODWILL AND INTANGIBLE ASSETS 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 millions) Balance as of December 31, 2021 $ 861.0 $ 1,121.7 $ 1,225.7 $ 3,208.3 Adjustments to goodwill for acquisitions (1) — 97.4 — 97.4 Foreign currency exchange rate changes (35.5) (10.2) (19.1) (64.8) Balance as of December 31, 2022 $ 825.5 $ 1,208.9 $ 1,206.5 $ 3,240.9 Adjustments to goodwill for acquisitions (1) — 0.9 — 0.9 Foreign currency exchange rate changes 12.6 1.8 6.1 20.5 Balance as of December 31, 2023 $ 838.1 $ 1,211.6 $ 1,212.6 $ 3,262.3 (1) Adjustments to goodwill reflect the preliminary allocation of the purchase price paid to acquire Rahi Systems, which is part of the CSS segment, and adjustments to the assets acquired and liabilities assumed since their initial measurement, as disclosed in Note 6, “Acquisitions and Disposals”. The components of intangible assets are as follows: December 31, 2023 December 31, 2022 Life (in years) Gross Carrying Amount (1) Accumulated Amortization (1) Net Gross Carrying Amount (1) Accumulated Amortization (1) Net (In millions) Intangible assets: Trademarks Indefinite $ 793.0 $ — $ 793.0 $ 792.1 $ — $ 792.1 Customer relationships 10 - 20 1,519.9 (464.4) 1,055.5 1,516.0 (377.6) 1,138.3 Distribution agreements 15 and 19 29.2 (26.0) 3.2 29.2 (24.4) 4.8 Trademarks 5 and 12 15.5 (9.6) 5.9 15.5 (7.4) 8.1 $ 2,357.6 $ (500.0) $ 1,857.6 $ 2,352.8 $ (409.4) $ 1,943.4 (1) Excludes the original cost and related accumulated amortization of fully-amortized intangible assets. Amortization expense related to intangible assets totaled $88.6 million, $92.9 million and $119.6 million for the years ended December 31, 2023, 2022 and 2021, respectively. 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 millions) 2024 $ 86.3 2025 83.2 2026 77.8 2027 74.9 2028 73.2 Thereafter 669.2 The Company performed its annual impairment tests of goodwill and indefinite-lived intangible assets during the fourth quarter of 2023 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 not necessary. 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, 2023
Business Combinations [Abstract]
ACQUISITIONS	Rahi Systems Holdings, Inc. On November 1, 2022, through its wholly-owned subsidiary WESCO Distribution, Inc. (“Wesco Distribution”), the Company acquired 100% of the equity securities of Rahi Systems Holdings, Inc. (“Rahi Systems” or “Rahi”). Headquartered in Fremont, California, Rahi Systems is a leading provider of global hyperscale data center solutions with over 900 employees in 25 countries. Rahi's expertise with complex information technology projects and global presence strengthen Wesco's data center solution offerings. Wesco Distribution funded the purchase price paid at closing with cash on hand as well as borrowings under its accounts receivable securitization and revolving credit facilities. The total fair value of consideration transferred for the acquisition of Rahi Systems consisted of the following: (In millions) Purchase price $ 217.0 Adjustments to purchase price 25.9 Total cash consideration 242.9 Extinguishment of Rahi Systems obligations 12.6 Total purchase consideration $ 255.4 Supplemental cash flow disclosure related to acquisitions: Cash paid for acquisition $ 255.4 Less: Cash acquired (68.6) Cash paid for acquisition, net of cash acquired $ 186.8 The purchase consideration was allocated to the identified assets acquired and liabilities assumed based on their respective acquisition date fair value, with the excess allocated to goodwill. The Company identified a customer relationship intangible asset and estimated its fair value using an income valuation method. The excess purchase consideration recorded as goodwill is not deductible for income tax purposes, and has been assigned to the Company's CSS reportable segment, as disclosed in Note 5, “Goodwill and Intangible Assets”. The resulting goodwill is primarily attributable to Rahi’s workforce and cross-selling opportunities in additional geographies. The estimated fair values of assets acquired and liabilities assumed were based on preliminary calculations and valuations using estimates and assumptions at the time of acquisition. During the fourth quarter of 2023, the Company finalized its allocation of the purchase consideration to the respective fair values of assets acquired and liabilities assumed in the acquisition of Rahi. As the Company obtained additional information during the measurement period, it recorded adjustments to its preliminary estimates of fair value, which were as of November 1, 2022. As presented in the table below, the net impact of these measurement period adjustments was an increase to goodwill of $0.9 million. The results of operations of Rahi Systems are included in the consolidated financial statements beginning on November 1, 2022, the acquisition date. For the years ended December 31, 2023 and 2022, the Consolidated Statements of Income and Comprehensive Income include $543.9 million and $111.5 million of net sales, respectively, and an immaterial amount of income from operations for Rahi Systems. The Company has not presented supplemental pro forma revenue and earnings of the combined business as the acquisition of Rahi Systems is not material to Wesco's consolidated financial statements. The following table sets forth the allocation of the purchase consideration to the respective fair values of assets acquired, liabilities assumed for the acquisition of Rahi Systems: Preliminary Fair Value Estimates (1) Measurement Period Adjustments Final Purchase Price Allocation (1) Assets (In millions) Cash and cash equivalents $ 68.6 $ — $ 68.6 Trade accounts receivable 52.6 — 52.6 Inventories 49.4 19.6 69.0 Intangible assets (2) 105.8 — 105.8 Goodwill 97.4 0.9 98.3 Other current and noncurrent assets 41.1 6.4 47.5 Total assets $ 415.0 $ 26.9 $ 441.8 Liabilities Accounts payable $ 58.0 $ 28.0 $ 86.0 Operating lease liabilities 20.1 — 20.1 Deferred income taxes 25.0 (7.2) 17.8 Other current and noncurrent liabilities 56.4 6.1 62.5 Total liabilities $ 159.5 $ 26.9 $ 186.4 Fair value of net assets acquired, including goodwill and intangible assets $ 255.4 $ — $ 255.4 (1) The preliminary fair value estimates are as of November 1, 2022. As disclosed above, the Company finalized its purchase price allocation during the measurement period. (2) Consists of a customer relationship intangible asset with an estimated weighted-average useful life of 17 years. Canadian Divestitures On August 6, 2020, the Company entered into a Consent Agreement with the Competition Bureau of Canada regarding the merger with Anixter International Inc. (“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 for the year ended December 31, 2020. 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.

PROPERTY, BUILDINGS AND EQUIPME

PROPERTY, BUILDINGS AND EQUIPMENT	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
PROPERTY, BUILDINGS AND EQUIPMENT	7. PROPERTY, BUILDINGS AND EQUIPMENT The following table sets forth the components of property, buildings and equipment: As of December 31, 2023 2022 (In millions) Buildings and leasehold improvements $ 202.6 $ 169.5 Furniture, fixtures and equipment 359.9 304.7 Software costs 292.6 272.6 855.1 746.7 Accumulated depreciation and amortization (502.5) (425.8) 352.6 320.9 Land 25.0 24.6 Construction in progress 46.0 57.1 Property, buildings and equipment, net $ 423.6 $ 402.7 Depreciation expense was $56.3 million, $47.8 million and $51.4 million, and capitalized software amortization was $36.4 million, $38.3 million and $27.5 million, in 2023, 2022 and 2021, respectively. As of December 31, 2023 and 2022, unamortized software costs were $78.2 million and $89.2 million, respectively. Furniture, fixtures and equipment include finance leases of $51.9 million and $38.8 million and related accumulated depreciation of $19.9 million and $17.1 million as of December 31, 2023 and 2022, respectively.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Lessee, Operating Leases	8. 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 millions) 2023 2022 Operating lease assets $ 761.2 $ 625.1 Current operating lease liabilities (1) 156.7 129.5 Noncurrent operating lease liabilities 641.7 510.4 Total operating lease liabilities $ 798.4 $ 640.0 (1) 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 millions) 2023 2022 2021 Operating lease cost $ 197.0 $ 175.8 $ 169.9 Short-term lease cost 8.9 4.8 3.6 Variable lease cost 53.2 45.7 49.5 Total lease cost $ 259.1 $ 226.4 $ 222.9 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 millions) 2023 2022 2021 Operating cash flows from operating leases $ 174.5 $ 171.7 $ 153.6 Right-of-use assets obtained in exchange for new operating lease liabilities (1) 296.9 267.1 157.5 (1) The year ended December 31, 2022 includes $20.1 million of operating lease liabilities acquired in the business combination with Rahi Systems, as disclosed in Note 6, “Acquisitions and Disposals”. As of December 31, 2023 and 2022, the weighted-average remaining lease term for operating leases was approximately 6 years. The weighted-average discount rate used to measure operating leases was 4.3% and 4.0% as of December 31, 2023 and 2022, respectively. The following table sets forth the maturities of the Company's operating lease liabilities and reconciles the respective undiscounted payments to the total operating lease liabilities in the Consolidated Balance Sheet as of December 31, 2023: (In millions) 2024 $ 191.2 2025 172.3 2026 146.7 2027 119.0 2028 87.4 Thereafter 188.8 Total undiscounted operating lease payments 905.4 Less: imputed interest (107.0) Total operating lease liabilities $ 798.4 Operating lease payments include $14.1 million related to options to extend real estate lease terms that are reasonably certain of being exercised. As of December 31, 2023, the Company has additional leases related to facilities that have not yet commenced totaling $45.7 million. These operating leases, which are not recorded in the Consolidated Balance Sheet as of December 31, 2023, will commence in 2024 with lease terms of 1 to 10 years.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	The following table sets forth Wesco’s outstanding indebtedness: As of December 31, 2023 2022 (In millions) International lines of credit $ 1.0 $ 7.1 Accounts Receivable Securitization Facility 1,550.0 1,535.0 Revolving Credit Facility 953.0 1,023.6 5.50% Anixter Senior Notes due 2023 — 58.6 6.00% Anixter Senior Notes due 2025 4.2 4.2 7.125% Senior Notes due 2025 1,500.0 1,500.0 7.250% Senior Notes due 2028, less debt discount of $5.6 and $6.8 in 2023 and 2022, respectively 1,319.4 1,318.2 Finance lease obligations 31.4 20.6 Total debt 5,359.0 5,467.3 Plus: Fair value adjustments to the Anixter Senior Notes 0.1 0.3 Less: Unamortized debt issuance costs (37.4) (51.1) Less: Short-term debt and current portion of long-term debt (1) (8.6) (70.5) Total long-term debt $ 5,313.1 $ 5,346.0 (1) As of December 31, 2022, short-term debt and current portion of long-term debt included the $58.6 million aggregate principal amount of the Company's 5.50% Anixter Senior Notes due 2023, which matured on March 1, 2023. 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 $10.0 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 the Company's 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 0.85% and 4.84% at December 31, 2023 and 2022, respectively. Accounts Receivable Securitization Facility Wesco Distribution has an 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, dated as of June 22, 2020. The Receivables Purchase Agreement amended and restated the receivables purchase agreement entered into on September 24, 2015 (the “Prior Receivables Purchase Agreement”). As of December 31, 2023, the Receivables Facility has a purchase limit of $1,625 million, with the opportunity to exercise an accordion feature that permits increases in the purchase limit up to an aggregate commitment of $1,750 million, subject to customary conditions, and a maturity date of March 1, 2025. The Receivables Facility has an interest rate spread of 1.05% and a commitment fee of 0.45%. As of December 31, 2023 and 2022, accounts receivable eligible for securitization totaled $2,146.9 million and $2,028.2 million, respectively. The Consolidated Balance Sheets as of December 31, 2023 and 2022 include $1,550.0 million and $1,535.0 million, respectively, of senior undivided interests in accounts receivable balances sold to third parties, as well as borrowings for equal amounts. At December 31, 2023, the interest rate for this facility was approximately 6.23%. Under the Receivables Facility, Wesco Distribution 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 Company's balance sheet, and Wesco recognizes the related secured borrowing. Wesco has agreed to continue servicing the receivables for the third-party conduits and financial institutions at market rates; accordingly, no servicing asset or liability has been recorded. On October 31, 2022, Wesco Distribution amended its Receivables Facility pursuant to the terms and conditions of a Sixth Amendment to Fifth Amended and Restated Receivables Purchase Agreement (the “Sixth Receivables Amendment”). The Sixth Receivables Amendment amended the Receivables Purchase Agreement to increase its purchase limit from $1,525 million to $1,625 million. The maturity date, interest rate spread and commitment fee of the Receivables Facility remained unchanged. On August 2, 2022, Wesco Distribution amended its Receivables Facility pursuant to the terms and conditions of a Fifth Amendment to Fifth Amended and Restated Receivables Purchase Agreement (the “Fifth Receivables Amendment”). The Fifth Receivables Amendment amended the Receivables Purchase Agreement to, among other things, increase the purchase limit under the Receivables Facility from $1,400 million to $1,525 million and to decrease the interest rate spread from 1.10% to 1.05%. The maturity date and commitment fee of the Receivables Facility remained unchanged. On March 1, 2022, Wesco Distribution amended its Receivables Facility pursuant to the terms and conditions of a Fourth Amendment to Fifth Amended and Restated Receivables Purchase Agreement (the “Fourth Receivables Amendment”). The Fourth Receivables Amendment, among other things, (i) increased the purchase limit under the Receivables Facility from $1,300 million to $1,400 million, (ii) increased the aggregate commitment under the accordion feature from $1,500 million to $1,750 million, and (iii) extended the maturity date from June 21, 2024 to March 1, 2025. Additionally, the Fourth Receivables Amendment replaced the LIBOR interest rate option with Secured Overnight Financing Rate-based (“SOFR”) interest rate options, including term SOFR and daily simple SOFR, and decreased the interest rate spread from 1.15% to 1.10%. The 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. 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. 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%. Revolving Credit Facility Wesco, Wesco Distribution and certain other subsidiaries of Wesco entered into a 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. As of December 31, 2023, the Revolving Credit Facility has revolving commitments of $1,725 million, a letter of credit sub-facility of up to $175 million, an accordion feature allowing Wesco Distribution to request increases to the borrowing commitments under the Revolving Credit Facility of up to $450 million in the aggregate, subject to customary conditions, and a sub-facility for loans denominated in Canadian dollars of $625 million. The Revolving Credit Facility has a maturity date of March 1, 2027 and permits the Company to declare and pay an aggregate amount of common stock dividends of up to $80 million per year. The applicable interest rate for borrowings under the Revolving Credit Facility, as amended, includes interest rate spreads based on available borrowing capacity that range from 1.00% to 1.50% for SOFR-based borrowings and from 0.00% to 0.50% for prime rate-based borrowings. At December 31, 2023, the interest rate for this facility was approximately 6.89%. During 2023, Wesco borrowed $2,997.2 million under the Revolving Credit Facility and made repayments in the aggregate amount of $3,067.5 million. During 2022, aggregate borrowings and repayments under the Revolving Credit Facility were $3,990.0 million and $3,557.1 million, respectively. Wesco had $736.0 million available under the Revolving Credit Facility at December 31, 2023, after giving effect to outstanding letters of credit and certain borrowings under the Company's international lines of credit, as compared to $664.9 million available under the Revolving Credit Facility at December 31, 2022, after giving effect to outstanding letters of credit and certain borrowings under the Company's international lines of credit. On October 31, 2022, Wesco Distribution amended its Revolving Credit Facility pursuant to the terms and conditions of a Fourth Amendment to Fourth Amended and Restated Credit Agreement (the “Fourth Revolver Amendment”). The Fourth Revolver Amendment amended the Revolving Credit Agreement to, among other things, increase the revolving commitments from $1,525 million to $1,725 million, increase the sub-facility for loans denominated in Canadian dollars from $600 million to $625 million, decrease the capacity to request increases in the aggregate revolving commitments from $650 million to $450 million, and increase the aggregate amount of common stock dividends that the Company may declare and pay from $50 million per year to $80 million per year. The maturity date and interest rate spreads of the Revolving Credit Facility remained unchanged. On August 2, 2022, Wesco Distribution amended its Revolving Credit Facility pursuant to the terms and conditions of a Third Amendment to Fourth Amended and Restated Credit Agreement (the “Third Revolver Amendment”). The Third Revolver Amendment amended the Revolving Credit Agreement to, among other things, increase the revolving commitments under the Revolving Credit Facility from $1,350 million to $1,525 million and to increase the sub-facility for loans denominated in Canadian dollars from $550 million to $600 million. The maturity date and interest rate spreads of the Revolving Credit Facility remained unchanged. On March 1, 2022, Wesco Distribution amended its Revolving Credit Facility pursuant to the terms and conditions of a Second Amendment to Fourth Amended and Restated Credit Agreement (the “Second Revolver Amendment”). The Second Revolver Amendment, among other things, (i) increased the revolving commitments under the Revolving Credit Facility from $1,200 million to $1,350 million, (ii) increased the sub-facility for loans denominated in Canadian dollars from $500 million to $550 million, (iii) increased the capacity to request increases in the aggregate revolving commitments from $400 million to $650 million, (iv) modified certain negative covenants to provide for additional flexibility, and (v) extended the maturity date from June 22, 2025 to March 1, 2027. Additionally, the Second Revolver Amendment replaced the LIBOR-based interest rate option with SOFR-based interest rate options, including term SOFR and daily simple SOFR. 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 “First 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 First 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 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. 5.50% Senior Notes due 2023 6.00% Senior Notes due 2025 On April 30, 2020, in connection with the merger with Anixter, 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. The Anixter 2023 Senior Notes matured on March 1, 2023, on which date Wesco Distribution repaid the $58.6 million aggregate principal amount of its Anixter 2023 Senior Notes plus accrued interest up to, but not including, the maturity date. The repayment was funded with borrowings under the Company's Revolving Credit Facility and had no impact on the Company's results of operations. The Anixter 2025 Senior Notes will mature on December 1, 2025. 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 with Anixter 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 with Anixter, 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. 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 of 1933, as amended (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 with Anixter and the other transactions contemplated by the Agreement and Plan of Merger dated January 10, 2020 (the “Merger Agreement”). The use of proceeds included (i) paying the cash portion of the 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. 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. 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. 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, 2023 and 2022, unamortized debt issuance costs of $37.4 million and $51.1 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, 2023. The following table sets forth the aggregate principal repayment requirements for all indebtedness for the next five years and thereafter, as of December 31, 2023: (In millions) 2024 $ 8.6 2025 3,063.6 2026 6.4 2027 957.3 2028 1,327.2 Thereafter 1.5 Total payments on debt $ 5,364.6 Debt discount (5.6) Total debt $ 5,359.0

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2023
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 Company's 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. In connection with the Company’s merger with Anixter, 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. On June 22, 2025, Wesco may redeem the Series A Preferred Stock, in whole or in part, for cash at a redemption price of $25,000 per share, plus all accrued and unpaid dividends. 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. These restrictions are based on availability, as defined in the respective credit agreements, as well as Wesco's compliance with certain fixed charge coverage tests. At December 31, 2023 and 2022, no dividends had been declared that remained unpaid 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. Share Repurchases On May 31, 2022, the Company's Board of Directors adopted a resolution authorizing the repurchase of up to $1 billion of the Company's common stock and Series A Preferred Stock. The share repurchase authorization has no expiration date and may be modified, suspended, or terminated at any time without prior notice. During the years ended December 31, 2023 and 2022, the Company entered into spot repurchase transactions through a broker to purchase 504,335 and 87,502 shares, respectively, of its common stock in the open market for cash totaling $75.0 million and $11.1 million, respectively. Wesco funded the repurchases with available cash and borrowings under its revolving credit facility and the repurchases were made within the limits described above. Dividends The Company's dividends on common stock are declared at the discretion of the Board of Directors. During the fiscal year ended December 31, 2023, the Board of Directors declared and the Company paid quarterly cash dividends totaling $76.6 million to common stockholders. The following table is a summary of cash dividends declared and paid on the Company's common stock for the year ended December 31, 2023: Date Declared Record Date Payment Date Amount per share Dividend Payment March 3, 2023 March 15, 2023 March 31, 2023 $ 0.375 $19.2 million June 1, 2023 June 15, 2023 June 30, 2023 $ 0.375 $19.2 million August 31, 2023 September 15, 2023 September 29, 2023 $ 0.375 $19.1 million November 30, 2023 December 15, 2023 December 29, 2023 $ 0.375 $19.1 million During 2023, the Company's Board of Directors also declared and the Company paid quarterly cash dividends of $0.664 per depositary share totaling $57.4 million.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
INCOME TAXES	11. INCOME TAXES The following table sets forth the components of income before income taxes by jurisdiction: Year Ended December 31, 2023 2022 2021 (In millions) United States $ 739.4 $ 859.4 $ 396.8 Foreign 252.6 277.3 185.1 Income before income taxes $ 992.0 $ 1,136.7 $ 581.9 The following table sets forth the components of the provision for income taxes: Year Ended December 31, 2023 2022 2021 (In millions) Current income taxes: Federal $ 124.8 $ 166.1 $ 107.9 State 34.6 43.0 30.2 Foreign 74.4 66.7 55.7 Total current income taxes 233.8 275.8 193.8 Deferred income taxes: Federal (1.0) (7.5) (62.3) State 2.7 0.7 (12.3) Foreign (9.6) 5.6 (3.7) Total deferred income taxes (7.9) (1.2) (78.3) Provision for income taxes $ 225.9 $ 274.5 $ 115.5 The following table sets forth the reconciliation between the federal statutory income tax rate and the effective tax rate: Year Ended December 31, 2023 2022 2021 Federal statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal income tax benefit 3.0 3.1 2.0 Tax effect of intercompany financing (0.9) (1.2) (3.2) Unrecognized tax benefits — 0.3 2.5 Nondeductible expenses — 0.3 0.6 Change in valuation allowance (0.9) (0.9) (2.8) Effect of cross-border tax laws 1.4 1.4 (1.1) Other (0.8) 0.2 0.9 Effective tax rate 22.8 % 24.2 % 19.9 % On August 16, 2022, the Inflation Reduction Act of 2022 was enacted into U.S. law, which includes implementation of a new corporate alternative minimum tax (“CAMT”), among other provisions. The CAMT imposes a minimum tax of 15% on the adjusted financial statement income (“AFSI”) of certain corporations with average annual AFSI over a three-year period in excess of $1 billion, so-called “applicable corporations”. CAMT is effective for tax years beginning after December 31, 2022. The Company was not subject to CAMT in 2023 and does not expect to be subject to it in 2024. The undistributed earnings of the Company's foreign subsidiaries amounted to approximately $2,194.1 million as of December 31, 2023. 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. Wesco has elected to pay the transition tax in installments over an eight year period ending in 2026. As of December 31, 2023, the Company's remaining liability for the transition tax was $53.8 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 $119.3 million would be payable upon the remittance of all previously undistributed foreign earnings as of December 31, 2023, 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, 2023 2022 (In millions) Assets Liabilities Assets Liabilities Accounts receivable $ 23.3 $ — $ 21.0 $ — Inventories 45.9 — 23.9 — Depreciation of property, buildings and equipment — 41.0 — 46.9 Operating leases 201.8 192.0 169.3 165.2 Amortization of intangible assets — 564.5 — 575.4 Employee benefits 21.5 — 36.5 — Stock-based compensation 11.2 — 14.1 — Prepaid royalty payments — — 14.0 — Disallowed business interest expense 1.9 — 4.8 — Net operating loss carryforwards 36.7 — 32.0 — Foreign tax credit carryforwards 41.1 — 52.2 — Other 38.3 10.3 37.3 10.5 Deferred income taxes before valuation allowance 421.7 807.8 405.1 797.9 Valuation allowance (23.5) — (33.7) — Total deferred income taxes $ 398.2 $ 807.8 $ 371.4 $ 797.9 Wesco had deferred tax assets of $31.4 million and $27.6 million as of December 31, 2023 and 2022, respectively, related to foreign net operating loss carryforwards. These net operating loss carryforwards expire beginning in 2026 through 2043, 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 $12.9 million and $16.7 million against deferred tax assets related to certain foreign net operating loss carryforwards as of December 31, 2023 and 2022, respectively. Additionally, these foreign jurisdictions had deferred tax assets of $6.1 million and $10.9 million as of December 31, 2023 and 2022, respectively, related to other future deductible temporary differences. The Company has recorded a full valuation allowance against these amounts as of December 31, 2023 and 2022, respectively. As of December 31, 2023 and 2022, Wesco had deferred tax assets of $3.0 million and $4.4 million, respectively, related to state net operating loss carryforwards. These net operating loss carryforwards expire beginning in 2024 through 2041, while some may be carried forward indefinitely. The Company has determined that certain state net operating loss carryforwards will not be realized. Accordingly, the Company has recorded a valuation allowance of $1.0 million against deferred tax assets related to certain state net operating loss carryforwards as of December 31, 2023. As of December 31, 2023 and 2022, Wesco had deferred tax assets of $1.9 million and $4.8 million, respectively, related to disallowed business interest expense for state income tax purposes. The carryforward period for disallowed business interest expense is indefinite. The Company has determined that certain state disallowed business interest expense carryforwards will not be realized. Accordingly, the Company has recorded a valuation allowance of $0.5 million against deferred tax assets related to certain state disallowed business interest expense carryforwards as of December 31, 2023. As of December 31, 2023 and 2022, Wesco had deferred tax assets of $41.1 million and $52.2 million, respectively, related to foreign tax credit carryforwards. The foreign tax credit carryforwards expire beginning in 2027 through 2033. 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 $2.9 million and $6.1 million against these deferred tax assets as of December 31, 2023 and 2022, 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 2020 and forward United States — Material States 2017 and forward Canada 2012 and forward UK 2018 and forward Australia 2018 and forward The following table sets forth the reconciliation of gross unrecognized tax benefits: As of December 31, 2023 2022 2021 (In millions) Beginning balance January 1 $ 109.3 $ 107.3 $ 68.1 Additions for current year tax positions 29.2 14.4 39.8 Additions for prior year tax positions 6.6 0.9 8.4 Additions for acquired tax positions 0.9 5.5 — Reductions for prior year tax positions (6.7) (1.8) (3.9) Settlements (2.5) — (0.1) Lapse in statute of limitations (15.8) (14.5) (3.8) Foreign currency exchange rate changes 0.3 (2.6) (1.2) Ending balance December 31 $ 121.3 $ 109.3 $ 107.3 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, 2023, 2022 and 2021 were $40.1 million, $40.6 million, and $36.1 million, respectively. Within the next twelve months, the amount of unrecognized tax benefits is expected to decrease by $16.5 million due to the expiration of statutes of limitation. Such change would result in a $7.6 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 Statements of Income and Comprehensive Income. The Company recognized interest income on unrecognized tax benefits of $1.1 million for the year ended December 31, 2023. The Company recognized interest expense on unrecognized tax benefits of $2.3 million and $0.9 million for the years ended December 31, 2022 and 2021, respectively. As of December 31, 2023 and 2022, Wesco had a liability of $8.9 million and $9.6 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. Penalties recorded in income tax expense for the years ended December 31, 2023 , 2022 and 2021 were immaterial. As of December 31, 2023 and 2022, Wesco had a liability of $4.7 million and $4.8 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 in the amount of approximately $26.0 million related to its 2012 income tax return. This amount, updated for adjustments required under Mexican law, was approximately $33.0 million as of December 31, 2023. The Company believes the assessment is without merit and has filed an annulment lawsuit in the Mexican Federal Court of Administrative Justice. The Company expects to prevail in this litigation and, accordingly, has not recognized a liability for this assessment in its consolidated financial statements. In July 2022, one of the Company's Canadian affiliates received tax assessments from the Canada Revenue Agency (“CRA”) totaling approximately $11.0 million, including tax and interest, related to its 2012 through 2014 income tax returns. The Company's Canadian affiliate received a related penalty assessment of approximately $2.7 million in May 2023. The Company believes these assessments are without merit and has appealed to the Tax Court of Canada. The Company intends to avail itself of all avenues to appeal, as necessary to overturn the assessments and expects to prevail. Therefore, the Company has not recognized a liability for these assessments in its consolidated financial statements. The CRA continues to audit the 2015 and 2016 tax years of Wesco's Canadian affiliates and has made inquiries into their 2017 through 2019 income tax returns. The Company expects to eventually receive similar assessments for these tax years.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2023
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, 2023 2022 2021 (In millions, except per share data) Net income attributable to WESCO International, Inc. $ 765.5 $ 860.5 $ 465.4 Less: Preferred stock dividends 57.4 57.4 57.4 Net income attributable to common stockholders $ 708.1 $ 803.1 $ 408.0 Weighted-average common shares outstanding used in computing basic earnings per share 51.1 50.7 50.3 Common shares issuable upon exercise of dilutive equity awards 1.2 1.7 1.7 Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share 52.3 52.4 52.0 Earnings per share attributable to common stockholders Basic $ 13.86 $ 15.83 $ 8.11 Diluted $ 13.54 $ 15.33 $ 7.84 The computation of diluted earnings per share attributable to common stockholders excludes stock-based awards that would have had an antidilutive effect on earnings per share. For the years ended December 31, 2023 and 2022, there were approximately 0.2 million and 0.1 million antidilutive stock-based awards, respectively. For the year ended December 31, 2021, there were no antidilutive stock-based awards.

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2023
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”), which provides employer matching contributions. Contributions are made in cash and employees have the option to transfer balances allocated to their accounts into any of the available investment options. Prior to January 1, 2022, the Company could 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 were attained. The amendments to the WESCO Distribution, Inc. Retirement Savings described below eliminated the discretionary employer contributions. Discretionary employer contribution charges of $13.1 million were incurred for the year ended December 31, 2021. Anixter Inc. sponsored a defined contribution plan that covered all of its non-union U.S. employees (the “Anixter Inc. Employee Savings Plan”). The employer match for the Anixter Inc. Employee Savings Plan was equal to 50% of a participant's contribution up to 5% of the participant's compensation. Anixter Inc. also made an annual contribution to the Anixter Inc. Employee Savings Plan on behalf of each active participant who was hired or rehired on or after July 1, 2015, or was not participating in the Anixter Inc. Pension Plan. The amount of the employer annual contribution was equal to either 2% or 2.5% of the participant’s compensation, as determined by the participant’s years of service. This contribution was 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 was 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 was amended to change the employer matching contribution from an amount equal to 50% of participants' total monthly contributions up to 6% of eligible compensation to 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”). Prior to January 1, 2022, the Company made 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 ranged from 5% to 7% of the respective participants' eligible compensation. Anixter Canada Inc. sponsored a defined contribution plan for certain employees of Anixter Canada Inc. and Anixter Power Solutions Canada Inc. (the “Anixter Canadian Defined Contribution Plan”), which provided 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 was merged with and into an amended Wesco Canadian Defined Contribution Plan. During the first quarter of 2022, participant account balances were transferred from the Anixter Canadian Defined Contribution Plan to the amended Wesco Canadian Defined Contribution Plan. The amended Wesco Canadian Defined Contribution Plan provides 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 also requires employees of EECOL Electric Corp. hired on or after January 1, 2022 to join this defined contribution plan, and permits enrollment for those not participating in the defined benefit plan described below. Wesco incurred charges of $73.4 million, $58.2 million, and $54.7 million for the years ended December 31, 2023, 2022 and 2021, 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, 2023 and 2022, the Company's obligation under the Wesco Deferred Compensation Plan was $27.4 million and $20.3 million, respectively, which is included 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 and settled it in the second quarter of 2021 by making lump sum payments of $42.8 million directly to participants. The Company used the proceeds from liquidating certain assets held in a Rabbi Trust arrangement of approximately $39.7 million, plus available cash, to fund the settlement of the Anixter Deferred Compensation Plan. 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. Effective January 1, 2013, the EECOL SERP was closed to new participants and existing participants became 100% vested. Participants of the EECOL SERP now contribute 4% of their earnings to the EECOL Plan. Anixter Inc. sponsors the Anixter Inc. Pension Plan, which was closed to entrants first hired or rehired on or after July 1, 2015, and various defined benefit pension plans covering employees of foreign subsidiaries in Canada and Europe (together with the EECOL Plan and the EECOL SERP, the “Foreign Plans”). The majority of the Company's 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 Anixter Inc. Pension Plan is funded as required by the Employee Retirement Income Security Act of 1974 (“ERISA”) and the Internal Revenue Service. With the exception of the EECOL SERP, which is an unfunded plan, the Foreign Plans are funded as required by applicable foreign laws. Anixter Inc. also sponsored the Anixter Inc. Executive Benefit Plan and the Supplemental Executive Retirement Plan (the “Anixter SERP”) (together with the Anixter Inc. Pension Plan, the “Domestic Plans”). In the fourth quarter of 2020, the Company terminated both the Anixter Inc. Executive Benefit Plan and the Anixter SERP. During the year ended December 31, 2021, the Company settled its liabilities for these plans 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: (i) freeze the benefits provided under the Anixter Inc. Pension Plan effective December 31, 2021, (ii) close participation in the EECOL Plan effective December 31, 2021, and (iii) 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 recognized during the fourth quarter of 2021. During the fourth quarter of 2022, the Company terminated the Anixter Inc. Pension Plan effective December 31, 2022. Accordingly, certain estimates that reflect the pending settlement of this plan were incorporated into the assumptions used to measure the respective projected benefit obligation as of December 31, 2023 and 2022. As the Anixter Inc. Pension Plan had previously been frozen, its termination did not result in any curtailment gain or loss for the years ended December 31, 2023 or 2022. The benefit obligation associated with this plan was partially settled during the fourth quarter of 2023 by making lump sum cash payments to participants totaling $110.9 million and the Company recognized settlement cost of $ 4.7 million On February 12, 2024, the remaining benefit obligation of the Anixter Inc. Pension Plan was settled through the purchase of single premium annuity contracts for total cash of $138.8 million. The purchase was funded entirely by the assets of the plan. The final remeasurement of the plan will occur in the first quarter of 2024. Unrealized gains or losses currently reported as components of other comprehensive income (loss) related to the benefit obligation of the Anixter Inc. Pension Plan will be recognized in a final settlement charge at that time. 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 millions) 2023 2022 2023 2022 2023 2022 Change in Projected Benefit Obligation Beginning balance $ 253.5 $ 301.8 $ 267.3 $ 424.1 $ 520.8 $ 725.9 Service cost — — 4.7 8.3 4.7 8.3 Interest cost 10.4 8.7 12.9 9.5 23.3 18.2 Participant contributions — — 1.0 0.9 1.0 0.9 Actuarial (gain) loss, including assumption changes 2.6 (47.1) 29.5 (133.9) 32.1 (181.0) Benefits paid from plan assets (8.1) (9.8) (11.7) (11.1) (19.8) (21.0) Benefits paid from Company assets — — (0.5) (0.5) (0.5) (0.5) Settlement (110.9) — (4.2) (0.2) (115.1) (0.2) Foreign currency exchange rate changes — — 10.1 (29.8) 10.1 (29.8) Ending balance $ 147.5 $ 253.5 $ 309.1 $ 267.3 $ 456.6 $ 520.8 Change in Plan Assets at Fair Value Beginning balance $ 285.1 $ 370.7 $ 267.6 $ 381.8 $ 552.7 $ 752.5 Actual return on plan assets 12.0 (75.8) 24.1 (87.7) 36.1 (163.5) Participant contributions — — 1.0 0.9 1.0 0.9 Employer contributions — — 10.2 11.3 10.2 11.3 Benefits paid (8.1) (9.8) (12.2) (11.1) (20.3) (21.0) Settlement (110.9) — (4.2) (0.2) (115.1) (0.2) Foreign currency exchange rate changes — — 9.2 (27.2) 9.2 (27.2) Ending balance $ 178.1 $ 285.1 $ 295.7 $ 267.6 $ 473.8 $ 552.7 Funded Status $ 30.6 $ 31.6 $ (13.4) $ 0.3 $ 17.2 $ 31.9 Amounts Recognized in the Consolidated Balance Sheets Other assets $ 30.6 $ 31.6 $ 18.0 $ 28.4 $ 48.6 $ 60.0 Other current liabilities — — (0.4) (0.4) (0.4) (0.4) Other noncurrent liabilities — — (31.0) (27.6) (31.0) (27.6) Net amount recognized $ 30.6 $ 31.6 $ (13.4) $ 0.3 $ 17.2 $ 31.9 Weighted Average Assumptions Used to Determine Benefit Obligations Discount rate 4.5 % 4.4 % 4.4 % 4.8 % 4.4 % 4.6 % Rate of compensation increase — % — % 3.3 % 3.4 % 3.3 % 3.4 % 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 2023 and 2022 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. The Company had nine plans at December 31, 2023 and seven plans at December 31, 2022 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 $215.0 million and $119.0 million, respectively, and the aggregate fair value of plan assets was $183.8 million and $91.0 million, respectively. At December 31, 2023 and 2022, the Company's accumulated benefit obligation was $147.5 million and $253.5 million, respectively, for the Domestic Plans and $302.5 million and $253.2 million, respectively, for the Foreign Plans. The Company had nine plans at December 31, 2023 and seven plans at December 31, 2022 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 $208.6 million and $113.7 million, respectively, and the aggregate fair value of plan assets was $183.8 million and $91.0 million, respectively. The following tables set forth the components of net periodic pension cost (benefit) for the Company's defined benefit plans: Domestic Plans Foreign Plans Total (In millions) 2023 2022 2021 2023 2022 2021 2023 2022 2021 Components of Net Periodic Pension Cost (Benefit) Service cost $ — $ — $ 3.0 $ 4.7 $ 8.3 $ 12.1 $ 4.7 $ 8.3 $ 15.2 Interest cost 10.4 8.7 8.2 12.9 9.5 9.8 23.3 18.2 18.0 Expected return on plan assets (9.6) (14.4) (17.1) (14.0) (17.6) (17.8) (23.6) (32.0) (34.9) Recognized actuarial (loss) gain — — — (2.3) (0.9) 0.1 (2.3) (0.9) 0.1 Curtailment — — (3.9) — — (32.7) — — (36.6) Settlement 4.7 — 0.3 (1.9) (0.1) (0.1) 2.8 (0.1) 0.2 Net periodic pension cost (benefit) $ 5.5 $ (5.7) $ (9.5) $ (0.6) $ (0.8) $ (28.5) $ 4.9 $ (6.5) $ (38.0) Service cost is reported as a component of selling, general and administrative expenses. The other components of net periodic pension cost (benefit) totaling net cost of $0.2 million for the year ended December 31, 2023 and net benefits of $14.8 million and $53.2 million for the years ended December 31, 2022 and 2021, respectively, are presented as components of other non-operating expense (income) (“other expense (income), net”). The following weighted-average actuarial assumptions were used to determine net periodic pension cost (benefit): Domestic Plans Foreign Plans Total 2023 2022 2021 2023 2022 2021 2023 2022 2021 Discount rate 4.4 % 2.9 % 2.6 % 4.8 % 2.4 % 2.0 % 4.6 % 2.6 % 2.3 % Expected return on plan assets 4.8 % 4.3 % 5.3 % 5.5 % 5.0 % 4.9 % 5.1 % 4.6 % 5.1 % Rate of compensation increase — % — % 3.8 % 3.4 % 3.4 % 3.2 % 3.4 % 3.4 % 3.4 % 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 historical plan asset returns combined with current market conditions to estimate the rate of return. 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 7.0% in 2023. 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 (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 millions) 2023 2022 Changes to Balance: Beginning balance, before tax effect $ (40.6) $ (58.8) Net actuarial loss arising in current year 19.6 14.5 Recognized actuarial loss 2.3 0.9 Settlement (2.8) 0.1 Foreign currency exchange rate changes (1.0) 2.6 Ending balance, before tax effect $ (22.5) $ (40.6) As of December 31, (In millions) 2023 2022 Components of Balance: Prior service credit $ (0.2) $ (0.2) Net actuarial gain (22.3) (40.5) Ending balance, before tax effect (22.5) (40.6) Tax effect 2.8 10.2 Ending balance, after tax effect $ (19.7) $ (30.4) The following benefit payments, which reflect expected future service, are expected to be paid as follows: (In millions) Domestic Plans Foreign Plans Total 2024 $ 148.6 $ 10.5 $ 159.1 2025 — 10.5 10.5 2026 — 11.5 11.5 2027 — 11.9 11.9 2028 — 15.7 15.7 2029 to 2033 — 94.3 94.3 The Company expects to contribute approximately $7.0 million to its Foreign Plans in 2024. The Company does not expect to make a contribution to its domestic qualified pension plan in 2024 due to its overfunded status and anticipated settlement in the first quarter of 2024, as described above. 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, 2023 Min Target Max Equities 4.0 % — % 4 % 35 % Debt securities: Domestic treasuries 17.3 — 17 — Corporate bonds 40.5 — 41 — Total debt securities 57.8 58 Cash equivalents 38.2 — 38 — 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2023 Min Target Max Equities 19.7 % 12 % 21 % 29 % Debt securities: Domestic treasuries 0.8 — 1 — Corporate bonds 3.2 1 1 31 Pooled investment funds and other 63.7 48 67 78 Total debt securities 67.7 69 Property/real estate 4.0 2 2 8 Insurance products 7.1 7 7 7 Other 1.5 — 1 8 100.0 % 100 % Domestic Plans Allocation Guidelines December 31, 2022 Min Target Max Equities 2.1 % — % 2 % 35 % Debt securities: Domestic treasuries 5.5 — 5 — Corporate bonds 22.4 — 22 — Other 7.6 — 8 35 Total debt securities 35.5 35 Property/real estate 13.5 — 14 35 Cash equivalents 48.9 — 49 — 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2022 Min Target Max Equities 27.3 % 19 % 30 % 38 % Debt securities: Domestic treasuries 0.2 — — — Corporate bonds 4.0 1 1 29 Pooled investment funds and other 52.6 36 54 67 Total debt securities 56.8 55 Property/real estate 4.0 2 4 7 Insurance products 6.9 7 7 7 Other 5.0 4 4 11 100.0 % 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 2023, 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 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 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, 2023 (In millions) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 7.2 $ 7.2 Debt securities: Domestic treasuries — — — 30.9 30.9 Corporate bonds — — — 72.0 72.0 Cash equivalents 68.0 — — — 68.0 Total investments in Domestic Plans $ 68.0 $ — $ — $ 110.1 $ 178.1 Foreign Plans Equities $ — $ — $ — $ 58.3 $ 58.3 Debt securities: Domestic treasuries — — — 2.4 2.4 Corporate bonds — — — 9.6 9.6 Pooled investment funds and other — — — 188.2 188.2 Property/real estate — — — 11.8 11.8 Insurance products — 20.9 — — 20.9 Other 4.5 — — — 4.5 Total investments in Foreign Plans $ 4.5 $ 20.9 $ — $ 270.3 $ 295.7 Total Equities $ — $ — $ — $ 65.5 $ 65.5 Debt securities: Domestic treasuries — — — 33.3 33.3 Corporate bonds — — — 81.6 81.6 Pooled investment funds and other — — — 188.2 188.2 Property/real estate — — — 11.8 11.8 Insurance products — 20.9 — — 20.9 Cash equivalents 68.0 — — — 68.0 Other 4.5 — — — 4.5 Total investments $ 72.5 $ 20.9 $ — $ 380.4 $ 473.8 (1) Investments measured at fair value using the net asset value ( “ 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, 2022 (In millions) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 5.9 $ 5.9 Debt securities: Domestic treasuries — — — 15.6 15.6 Corporate bonds — — — 63.8 63.8 Other — — — 21.7 21.7 Property/real estate — — — 38.7 38.7 Cash equivalents 139.4 — — — 139.4 Total investments in Domestic Plans $ 139.4 $ — $ — $ 145.7 $ 285.1 Foreign Plans Equities $ — $ — $ — $ 73.1 $ 73.1 Debt securities: Domestic treasuries — — — 0.4 0.4 Corporate bonds — — — 10.7 10.7 Pooled investment funds and other — — — 141.0 141.0 Property/real estate — — — 10.6 10.6 Insurance products — 18.5 — — 18.5 Other 3.7 — — 9.6 13.3 Total investments in Foreign Plans $ 3.7 $ 18.5 $ — $ 245.4 $ 267.6 Total Equities $ — $ — $ — $ 79.0 $ 79.0 Debt securities: Domestic treasuries — — — 16.0 16.0 Corporate bonds — — — 74.6 74.6 Pooled investment funds and other — — — 162.7 162.7 Property/real estate — — — 49.3 49.3 Insurance products — 18.5 — — 18.5 Cash equivalents 139.4 — — — 139.4 Other 3.7 — — 9.6 13.3 Total investments $ 143.1 $ 18.5 $ — $ 391.1 $ 552.7 (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 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 Prior to its acquisition by Wesco on June 22, 2020, Anixter granted restricted stock units 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 Company's merger with Anixter, were converted into cash-only settled Wesco phantom stock units, which vested ratably over a 3-year period. As of December 31, 2023, these awards had fully vested and have no remaining fair value or liability. As of December 31, 2022, the estimated fair value of these awards was $8.1 million and the Company's liability for these awards was $8.0 million, which is included in accrued payroll and benefit costs in the Consolidated Balance Sheet. The Company recognized compensation expense associated with these awards of $0.1 million, $2.6 million, and $13.6 million for the years ended December 31, 2023, 2022, and 2021, respectively, which is reported as a component of selling, general and administrative expenses.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2023
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, 2023, 1,877,701 shares of common stock were reserved under the 2021 Plan for future equity award grants. Stock-based compensation awards outstanding under Wesco's plans comprise stock options, 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 options and 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 participant behavior that is reviewed on at least an annual basis. For stock options and 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 options and 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 that were granted under the 1999 Plan vest fully on the third anniversary of the date of grant, except for the special award described below, which vested in tranches. Restricted stock units awarded under the 2021 Plan 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, as described below. Outstanding awards would vest upon the consummation of a change in control transaction with performance-based awards vesting 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 vested 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 to continued employment through the applicable anniversary date. Performance-based awards 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. 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. Wesco recognized $48.1 million, $46.4 million and $30.8 million of non-cash stock-based compensation expense for the years ended December 31, 2023, 2022 and 2021, respectively, which is included in selling, general and administrative expenses for all such periods. As of December 31, 2023, there was $50.2 million of total unrecognized compensation expense related to non-vested stock-based compensation arrangements for all awards previously made, which is expected to be recognized as follows: For the year ending December 31, (In millions) 2024 $ 32.2 2025 16.1 2026 1.9 The aggregate intrinsic value of awards exercised during the years ended December 31, 2023, 2022, and 2021 was $172.8 million, $68.3 million, and $69.7 million, respectively. The gross income tax benefit associated with the exercise of stock-based awards totaled $40.8 million, $15.8 million, and $16.8 million in 2023, 2022, and 2021, respectively. During the years ended December 31, 2023, 2022 and 2021, Wesco granted the following stock options, stock-settled stock appreciation rights, restricted stock units, and performance-based awards at the following weighted-average fair values: Year Ended December 31, 2023 2022 2021 Stock options granted 78,729 92,799 — Weighted-average fair value $ 76.69 $ 57.15 n/a Stock-settled stock appreciation rights granted — — 139,592 Weighted-average fair value n/a n/a $ 33.19 Restricted stock units granted 177,659 234,800 314,480 Weighted-average fair value $ 169.65 $ 122.13 $ 77.81 Performance-based awards granted (1) 212,656 83,991 122,812 Weighted-average fair value (1) $ 87.04 $ 122.09 $ 76.76 (1) As described further below, the year ended December 31, 2023 includes performance-based awards granted in February 2020 for which actual achievement levels were certified in February 2023, as well as performance-based awards granted during the year ended December 31, 2023. The fair values of stock options and stock-settled stock appreciation rights, as disclosed in the table above, were estimated using the following weighted-average assumptions in the respective periods: Year Ended December 31, 2023 2022 2021 Risk free interest rate 4.1% 2.0% 0.8% Expected life (in years) 5 7 7 Expected volatility 50% 43% 41% Expected dividend yield 0.89% n/a n/a 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, the expected volatility is based on the volatility of the Company's daily stock price over the expected life preceding the grant date of the award, and the expected dividend yield is based on the calculated yield on the Company's common stock at date of grant using the current year projected dividend distribution rate. The Company did not pay dividends to holders of its common stock during the years ended December 31, 2022 and 2021. The following table sets forth a summary of stock options and related information for the periods presented: Year Ended December 31, 2023 2022 Awards Weighted-Average Weighted-Average Remaining Contractual Life (In years) Aggregate Awards Weighted-Average Beginning of year 87,347 $ 121.55 — $ — Granted 78,729 169.72 92,799 121.58 Exercised (1,279) 122.09 — — Forfeited (1,715) 148.67 (5,452) 122.09 End of year 163,082 144.51 8.6 $ 4.8 87,347 121.55 Exercisable at end of year 28,411 $ 121.53 8.1 $ 1.5 879 $ 122.09 For the year ended December 31, 2023, the aggregate intrinsic value of stock options exercised during such period was not material. The following table sets forth a summary of stock-settled stock appreciation rights and related information for the periods presented: Year Ended December 31, 2023 2022 2021 Awards Weighted-Average Weighted-Average Aggregate Awards Weighted-Average Awards Weighted-Average Beginning of year 1,248,115 $ 62.02 1,370,388 $ 62.09 2,161,556 $ 60.48 Granted — — — — 139,592 77.05 Exercised (428,500) 66.70 (113,382) 61.90 (916,906) 60.70 Forfeited (1,331) 74.57 (8,891) 73.35 (13,854) 54.42 End of year 818,284 59.55 5.0 $ 93.6 1,248,115 62.02 1,370,388 62.09 Exercisable at end of year 777,479 $ 58.64 4.9 $ 89.6 1,083,320 $ 61.91 1,001,708 $ 62.79 For the year ended December 31, 2023, the aggregate intrinsic value of stock-settled appreciation rights exercised during such period was $40.2 million. The following table sets forth a summary of restricted stock units and related information for the periods presented: Year Ended December 31, 2023 2022 2021 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 774,233 $ 73.79 974,162 $ 53.48 921,495 $ 43.15 Granted 177,659 169.65 234,800 122.13 314,480 77.81 Vested (508,173) 59.72 (393,194) 53.13 (232,152) 44.10 Forfeited (36,106) 137.28 (41,535) 66.30 (29,661) 63.86 Unvested at end of year 407,613 $ 127.49 774,233 $ 73.79 974,162 $ 53.48 The following table sets forth a summary of performance-based awards and related information for the periods presented: Year Ended December 31, 2023 2022 2021 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 335,329 $ 75.26 380,819 $ 59.23 305,269 $ 52.61 Granted (1) 212,656 87.04 83,991 122.09 122,812 76.76 Vested (289,394) 48.32 (115,394) 54.64 (22,371) 62.80 Forfeited (3,732) 111.00 (14,087) 60.75 (24,891) 61.26 Unvested at end of year 254,859 $ 115.15 335,329 $ 75.26 380,819 $ 59.23 (1) Includes 63,098 performance-based awards granted in February 2023 with a fair value of $171.96 and three-year performance period ending December 31, 2025, and 144,697 of additional performance-based awards related to awards originally granted in February 2020 with a fair value of $48.32 and three-year performance period ended December 31, 2022 for which actual achievement levels were certified in February 2023. Also includes 3,074, 662, and 549 performance-based awards granted during the three months ended June 30, 2023, September 30, 2023, and December 31, 2023, respectively, with weighted-average fair values of $150.32, $115.04, and $115.21, respectively, and three-year performance periods ending December 31, 2025.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2023
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, 2023, the Company had $60.9 million in outstanding letters of credit and guarantees.

BUSINESS SEGMENTS

BUSINESS SEGMENTS	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
SEGMENTS AND RELATED INFORMATION	16. BUSINESS SEGMENTS The Company has operating segments comprising 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 on net sales, adjusted earnings before interest, taxes, depreciation and amortization (“EBITDA”), and adjusted EBITDA margin percentage. The Company incurs corporate costs primarily related to treasury, tax, information technology, legal and other centralized functions. The Company also has various corporate assets. 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 is a description of each of the Company's reportable segments and their business activities. Electrical & Electronic Solutions The EES segment, with approximately 6,800 employees supporting customers in more than 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 approximately 4,400 employees supporting customers in more than 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 approximately 2,900 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. The following tables set forth financial information by reportable segment for the periods presented: (In millions) Year Ended December 31, 2023 EES CSS UBS Total Net sales $ 8,610.3 $ 7,152.2 $ 6,622.7 $ 22,385.2 Year Ended December 31, 2022 (In millions) EES CSS UBS Total Net sales $ 8,823.3 $ 6,401.5 $ 6,195.3 $ 21,420.1 Year Ended December 31, 2021 (In millions) EES CSS UBS Total Net sales $ 7,621.3 $ 5,715.2 $ 4,881.0 $ 18,217.5 (In millions) Year Ended December 31, 2023 EES CSS UBS Adjusted EBITDA $ 727.4 $ 683.8 $ 739.3 Adjusted EBITDA margin % 8.4 % 9.6 % 11.2 % Year Ended December 31, 2022 (In millions) EES CSS UBS Adjusted EBITDA $ 851.3 $ 599.0 $ 677.3 Adjusted EBITDA margin % 9.6 % 9.4 % 10.9 % Year Ended December 31, 2021 (In millions) EES CSS UBS Adjusted EBITDA $ 604.5 $ 480.8 $ 428.4 Adjusted EBITDA margin % 7.9 % 8.4 % 8.8 %

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2022
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 millions) Year Ended December 31, 2023 $ 46.5 $ 18.6 $ — $ (9.2) $ 55.9 Year Ended December 31, 2022 41.7 18.0 — (13.2) 46.5 Year Ended December 31, 2021 23.9 12.9 13.7 (8.8) 41.7 (1) For the year ended December 31, 2021, 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 Deductions (1) end of period Allowance for deferred tax assets (In millions) Year Ended December 31, 2023 $ 33.7 $ 7.7 $ — $ (17.9) $ 23.5 Year Ended December 31, 2022 46.3 5.8 — (18.4) 33.7 Year Ended December 31, 2021 60.6 1.1 1.8 (17.3) 46.3 (1) For the year ended December 31, 2023, deductions primarily relate to a decrease in the valuation allowance recorded against deferred tax assets related to certain foreign jurisdictions. For the years ended December 31, 2022 and 2021, deductions primarily relate to 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, 2023
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. In the first quarter of the fiscal year ended December 31, 2023, we changed our presentation in tables from thousands to millions. Certain amounts as of December 31, 2023 and 2022 and for the years ended December 31, 2023, 2022 and 2021 in the consolidated financial statements and associated notes may not foot or recalculate due to rounding. Reclassifications The Consolidated Statements of Cash Flows and the reconciliation between the federal statutory income tax rate and the effective tax rate in Note 11, “Income Taxes” for the years ended December 31, 2022 and 2021, 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 or the effective tax rates 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 generally 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 $233.1 million at December 31, 2023 and $246.2 million at December 31, 2022. Supplier volume rebate income as a percentage of net sales was 1.4% in 2023, 1.6% in 2022 and 1.4% in 2021. Supplier Finance Programs The Company has supplier finance programs that are administered by intermediaries. Under these arrangements, participating suppliers may elect to receive early payment of invoices that have been confirmed by the Company, less an interest deduction or fees paid by the supplier, which is paid to the supplier by third-party finance providers. Wesco agrees to pay the stated amount of confirmed invoices in full on the original due date of the invoices, which is typically within 45 to 180 days of the invoice date, regardless of whether the supplier elects to receive early payment from the third-party finance providers. The Company does not provide assets pledged as security or other forms of guarantees to the finance providers or intermediaries under these arrangements. As of December 31, 2023 and 2022, the amounts due to suppliers that participate in the Company's supplier finance programs were approximately $ 32.6 million 30.7 million Cash and Cash Equivalents Cash equivalents are defined as highly liquid investments with original maturities of 90 days or less when purchased. Cash and cash equivalents in the Consolidated Balance Sheets include $21.9 million and $21.2 million as of December 31, 2023 and 2022, respectively, that is restricted from use to fund operations. 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 $55.9 million at December 31, 2023 and $46.5 million at December 31, 2022. The total amount recorded as selling, general and administrative expense related to credit losses was $18.6 million, $18.0 million and $12.9 million for 2023, 2022 and 2021, respectively. Inventories Inventories primarily consist of merchandise purchased for resale and are stated at the lower of cost or 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. The carrying value of inventories reflect reductions for excess and obsolescence of $113.4 million and $70.0 million at December 31, 2023 and 2022, respectively. The total expense related to excess and obsolete inventories, which is included in cost of goods sold, was $63.1 million, $43.2 million and $37.1 million for 2023, 2022 and 2021, 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 three to eight 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 $423.6 million net book value of property, buildings and equipment as of December 31, 2023, $152.8 million consists of land, buildings and leasehold improvements that are geographically dispersed among Wesco’s nearly 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, among others, 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 has elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of twelve 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 on a secured basis 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 as of October 1, 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 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, 2023 and 2022, goodwill and indefinite-lived trademarks totaled $4.1 billion and $4.0 billion, respectively. The determination of fair value involves significant management judgment, particularly as it relates to the underlying assumptions and factors around future 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 5 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. Cloud Computing Arrangements 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 $195.4 million and $104.1 million as of December 31, 2023 and 2022, respectively, and the related accumulated amortization was $15.5 million and $6.1 million, respectively. 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 $28.1 million and $28.0 million at December 31, 2023 and 2022, 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 consistent with amounts 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 functional currency for most of the Company's operations outside the U.S. is generally the applicable local currency. 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. The Company may re-evaluate the functional currencies of certain operations outside the U.S. if there are significant changes to operations that indicate that a change in functional currency may be necessary. Defined Benefit Pension Plans 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 expense (income), 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 expense (income), net”) primarily includes the non-service cost components of net periodic pension cost (benefit) and foreign exchange gains and losses. Recently Adopted and Recently Issued Accounting Standards In September 2022, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2022-04, Supplier Finance Programs (Subtopic 405-50): Disclosure of Supplier Finance Program Obligations , which requires that a buyer in a supplier finance program disclose sufficient information about the program to allow a user of financial statements to understand the program's nature, activity during the period, changes from period to period, and potential magnitude. The amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, except for the amendment on rollforward information, which is effective for fiscal years beginning after December 15, 2023. The Company adopted this ASU in the first quarter of 2023, except for the amendment on rollforward information, which the Company will begin disclosing in its Annual Report on Form 10-K for the fiscal year ending December 31, 2024. The adoption of this ASU resulted in additional disclosure of the Company's supplier finance programs. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances prior reportable segment disclosure requirements in part by requiring entities to disclose significant expenses related to their reportable segments. The amendments in this ASU are effective on a retrospective basis for annual periods beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. Management is currently evaluating the impact that this accounting standard will have on its consolidated financial statements and notes thereto. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this ASU are effective for annual periods beginning after December 15, 2024 on a prospective basis. Management is currently evaluating the impact that this accounting standard will have on its 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. In the first quarter of the fiscal year ended December 31, 2023, we changed our presentation in tables from thousands to millions. Certain amounts as of December 31, 2023 and 2022 and for the years ended December 31, 2023, 2022 and 2021 in the consolidated financial statements and associated notes may not foot or recalculate due to rounding.
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 generally 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 $233.1 million at December 31, 2023 and $246.2 million at December 31, 2022. Supplier volume rebate income as a percentage of net sales was 1.4% in 2023, 1.6% in 2022 and 1.4% in 2021.
Cash Equivalents	Cash and Cash Equivalents Cash equivalents are defined as highly liquid investments with original maturities of 90 days or less when purchased. Cash and cash equivalents in the Consolidated Balance Sheets include $21.9 million and $21.2 million as of December 31, 2023 and 2022, respectively, that is restricted from use to fund operations.
Allowance for Doubtful Accounts	Allowance for Expected Credit Losses
Inventories	Inventories Inventories primarily consist of merchandise purchased for resale and are stated at the lower of cost or 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. The carrying value of inventories reflect reductions for excess and obsolescence of $113.4 million and $70.0 million at December 31, 2023 and 2022, respectively. The total expense related to excess and obsolete inventories, which is included in cost of goods sold, was $63.1 million, $43.2 million and $37.1 million for 2023, 2022 and 2021, 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 three to eight 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 $423.6 million net book value of property, buildings and equipment as of December 31, 2023, $152.8 million consists of land, buildings and leasehold improvements that are geographically dispersed among Wesco’s nearly 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, among others, 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 has elected the short-term lease measurement and recognition exemption; therefore, leases with an initial term of twelve 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 on a secured basis 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 as of October 1, 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 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, 2023 and 2022, goodwill and indefinite-lived trademarks totaled $4.1 billion and $4.0 billion, respectively. The determination of fair value involves significant management judgment, particularly as it relates to the underlying assumptions and factors around future 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 Definite-lived intangible assets are amortized over 5 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. Cloud Computing Arrangements 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 $195.4 million and $104.1 million as of December 31, 2023 and 2022, respectively, and the related accumulated amortization was $15.5 million and $6.1 million, respectively.
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 $28.1 million and $28.0 million at December 31, 2023 and 2022, 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 consistent with amounts 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 functional currency for most of the Company's operations outside the U.S. is generally the applicable local currency. 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. The Company may re-evaluate the functional currencies of certain operations outside the U.S. if there are significant changes to operations that indicate that a change in functional currency may be necessary.
Pension and Other Postretirement Plans, Pensions, Policy [Policy Text Block]	Defined Benefit Pension Plans 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 expense (income), 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 expense (income), 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 and Recently Issued Accounting Standards
New Accounting Pronouncements, Policy	Recently Adopted and Recently Issued Accounting Standards In September 2022, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2022-04, Supplier Finance Programs (Subtopic 405-50): Disclosure of Supplier Finance Program Obligations , which requires that a buyer in a supplier finance program disclose sufficient information about the program to allow a user of financial statements to understand the program's nature, activity during the period, changes from period to period, and potential magnitude. The amendments in this ASU are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, except for the amendment on rollforward information, which is effective for fiscal years beginning after December 15, 2023. The Company adopted this ASU in the first quarter of 2023, except for the amendment on rollforward information, which the Company will begin disclosing in its Annual Report on Form 10-K for the fiscal year ending December 31, 2024. The adoption of this ASU resulted in additional disclosure of the Company's supplier finance programs. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances prior reportable segment disclosure requirements in part by requiring entities to disclose significant expenses related to their reportable segments. The amendments in this ASU are effective on a retrospective basis for annual periods beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. Management is currently evaluating the impact that this accounting standard will have on its consolidated financial statements and notes thereto. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this ASU are effective for annual periods beginning after December 15, 2024 on a prospective basis. Management is currently evaluating the impact that this accounting standard will have on its 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, 2023
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 millions) 2023 2022 2021 Electrical & Electronic Solutions $ 8,610.3 $ 8,823.3 $ 7,621.3 Communications & Security Solutions 7,152.2 6,401.5 5,715.2 Utility & Broadband Solutions 6,622.7 6,195.3 4,881.0 Total by segment $ 22,385.2 $ 21,420.1 $ 18,217.5 Year Ended December 31, (In millions) 2023 2022 2021 United States $ 16,609.1 $ 15,857.3 $ 13,157.9 Canada 2,968.2 3,021.4 2,747.2 Other International (1) 2,807.9 2,541.4 2,312.5 Total by geography (2) $ 22,385.2 $ 21,420.1 $ 18,217.5 (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, 2023
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 millions) Balance as of December 31, 2021 $ 861.0 $ 1,121.7 $ 1,225.7 $ 3,208.3 Adjustments to goodwill for acquisitions (1) — 97.4 — 97.4 Foreign currency exchange rate changes (35.5) (10.2) (19.1) (64.8) Balance as of December 31, 2022 $ 825.5 $ 1,208.9 $ 1,206.5 $ 3,240.9 Adjustments to goodwill for acquisitions (1) — 0.9 — 0.9 Foreign currency exchange rate changes 12.6 1.8 6.1 20.5 Balance as of December 31, 2023 $ 838.1 $ 1,211.6 $ 1,212.6 $ 3,262.3 (1) Adjustments to goodwill reflect the preliminary allocation of the purchase price paid to acquire Rahi Systems, which is part of the CSS segment, and adjustments to the assets acquired and liabilities assumed since their initial measurement, as disclosed in Note 6, “Acquisitions and Disposals”.
Schedule of Intangible Assets by Major Class	The components of intangible assets are as follows: December 31, 2023 December 31, 2022 Life (in years) Gross Carrying Amount (1) Accumulated Amortization (1) Net Gross Carrying Amount (1) Accumulated Amortization (1) Net (In millions) Intangible assets: Trademarks Indefinite $ 793.0 $ — $ 793.0 $ 792.1 $ — $ 792.1 Customer relationships 10 - 20 1,519.9 (464.4) 1,055.5 1,516.0 (377.6) 1,138.3 Distribution agreements 15 and 19 29.2 (26.0) 3.2 29.2 (24.4) 4.8 Trademarks 5 and 12 15.5 (9.6) 5.9 15.5 (7.4) 8.1 $ 2,357.6 $ (500.0) $ 1,857.6 $ 2,352.8 $ (409.4) $ 1,943.4 (1) Excludes the original cost and related accumulated amortization of fully-amortized intangible assets.
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 millions) 2024 $ 86.3 2025 83.2 2026 77.8 2027 74.9 2028 73.2 Thereafter 669.2

PROPERTY, BUILDINGS AND EQUIP_2

PROPERTY, BUILDINGS AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2023
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, 2023 2022 (In millions) Buildings and leasehold improvements $ 202.6 $ 169.5 Furniture, fixtures and equipment 359.9 304.7 Software costs 292.6 272.6 855.1 746.7 Accumulated depreciation and amortization (502.5) (425.8) 352.6 320.9 Land 25.0 24.6 Construction in progress 46.0 57.1 Property, buildings and equipment, net $ 423.6 $ 402.7

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2023
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 millions) 2023 2022 2021 Operating lease cost $ 197.0 $ 175.8 $ 169.9 Short-term lease cost 8.9 4.8 3.6 Variable lease cost 53.2 45.7 49.5 Total lease cost $ 259.1 $ 226.4 $ 222.9
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 millions) 2023 2022 2021 Operating cash flows from operating leases $ 174.5 $ 171.7 $ 153.6 Right-of-use assets obtained in exchange for new operating lease liabilities (1) 296.9 267.1 157.5 (1) The year ended December 31, 2022 includes $20.1 million of operating lease liabilities acquired in the business combination with Rahi Systems, as disclosed in Note 6, “Acquisitions and Disposals”.
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 total operating lease liabilities in the Consolidated Balance Sheet as of December 31, 2023: (In millions) 2024 $ 191.2 2025 172.3 2026 146.7 2027 119.0 2028 87.4 Thereafter 188.8 Total undiscounted operating lease payments 905.4 Less: imputed interest (107.0) Total operating lease liabilities $ 798.4
AssetsAndLiabilitiesLesseeTableTextBlock	The following table sets forth supplemental balance sheet information related to operating leases for the periods presented: As of December 31, (In millions) 2023 2022 Operating lease assets $ 761.2 $ 625.1 Current operating lease liabilities (1) 156.7 129.5 Noncurrent operating lease liabilities 641.7 510.4 Total operating lease liabilities $ 798.4 $ 640.0 (1) 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, 2023
Debt Disclosure [Abstract]
Schedule of Debt	The following table sets forth Wesco’s outstanding indebtedness: As of December 31, 2023 2022 (In millions) International lines of credit $ 1.0 $ 7.1 Accounts Receivable Securitization Facility 1,550.0 1,535.0 Revolving Credit Facility 953.0 1,023.6 5.50% Anixter Senior Notes due 2023 — 58.6 6.00% Anixter Senior Notes due 2025 4.2 4.2 7.125% Senior Notes due 2025 1,500.0 1,500.0 7.250% Senior Notes due 2028, less debt discount of $5.6 and $6.8 in 2023 and 2022, respectively 1,319.4 1,318.2 Finance lease obligations 31.4 20.6 Total debt 5,359.0 5,467.3 Plus: Fair value adjustments to the Anixter Senior Notes 0.1 0.3 Less: Unamortized debt issuance costs (37.4) (51.1) Less: Short-term debt and current portion of long-term debt (1) (8.6) (70.5) Total long-term debt $ 5,313.1 $ 5,346.0
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, 2023: (In millions) 2024 $ 8.6 2025 3,063.6 2026 6.4 2027 957.3 2028 1,327.2 Thereafter 1.5 Total payments on debt $ 5,364.6 Debt discount (5.6) Total debt $ 5,359.0

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2023
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, 2023 2022 2021 (In millions) United States $ 739.4 $ 859.4 $ 396.8 Foreign 252.6 277.3 185.1 Income before income taxes $ 992.0 $ 1,136.7 $ 581.9
Schedule of Components of Income Tax Expense	The following table sets forth the components of the provision for income taxes: Year Ended December 31, 2023 2022 2021 (In millions) Current income taxes: Federal $ 124.8 $ 166.1 $ 107.9 State 34.6 43.0 30.2 Foreign 74.4 66.7 55.7 Total current income taxes 233.8 275.8 193.8 Deferred income taxes: Federal (1.0) (7.5) (62.3) State 2.7 0.7 (12.3) Foreign (9.6) 5.6 (3.7) Total deferred income taxes (7.9) (1.2) (78.3) Provision for income taxes $ 225.9 $ 274.5 $ 115.5
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, 2023 2022 2021 Federal statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal income tax benefit 3.0 3.1 2.0 Tax effect of intercompany financing (0.9) (1.2) (3.2) Unrecognized tax benefits — 0.3 2.5 Nondeductible expenses — 0.3 0.6 Change in valuation allowance (0.9) (0.9) (2.8) Effect of cross-border tax laws 1.4 1.4 (1.1) Other (0.8) 0.2 0.9 Effective tax rate 22.8 % 24.2 % 19.9 % On August 16, 2022, the Inflation Reduction Act of 2022 was enacted into U.S. law, which includes implementation of a new corporate alternative minimum tax (“CAMT”), among other provisions. The CAMT imposes a minimum tax of 15% on the adjusted financial statement income (“AFSI”) of certain corporations with average annual AFSI over a three-year period in excess of $1 billion, so-called “applicable corporations”. CAMT is effective for tax years beginning after December 31, 2022. The Company was not subject to CAMT in 2023 and does not expect to be subject to it in 2024.
Schedule of Deferred Tax Assets and Liabilities	The following table sets forth deferred tax assets and liabilities: As of December 31, 2023 2022 (In millions) Assets Liabilities Assets Liabilities Accounts receivable $ 23.3 $ — $ 21.0 $ — Inventories 45.9 — 23.9 — Depreciation of property, buildings and equipment — 41.0 — 46.9 Operating leases 201.8 192.0 169.3 165.2 Amortization of intangible assets — 564.5 — 575.4 Employee benefits 21.5 — 36.5 — Stock-based compensation 11.2 — 14.1 — Prepaid royalty payments — — 14.0 — Disallowed business interest expense 1.9 — 4.8 — Net operating loss carryforwards 36.7 — 32.0 — Foreign tax credit carryforwards 41.1 — 52.2 — Other 38.3 10.3 37.3 10.5 Deferred income taxes before valuation allowance 421.7 807.8 405.1 797.9 Valuation allowance (23.5) — (33.7) — Total deferred income taxes $ 398.2 $ 807.8 $ 371.4 $ 797.9
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 2020 and forward United States — Material States 2017 and forward Canada 2012 and forward UK 2018 and forward Australia 2018 and forward
Summary of Income Tax Contingencies	The following table sets forth the reconciliation of gross unrecognized tax benefits: As of December 31, 2023 2022 2021 (In millions) Beginning balance January 1 $ 109.3 $ 107.3 $ 68.1 Additions for current year tax positions 29.2 14.4 39.8 Additions for prior year tax positions 6.6 0.9 8.4 Additions for acquired tax positions 0.9 5.5 — Reductions for prior year tax positions (6.7) (1.8) (3.9) Settlements (2.5) — (0.1) Lapse in statute of limitations (15.8) (14.5) (3.8) Foreign currency exchange rate changes 0.3 (2.6) (1.2) Ending balance December 31 $ 121.3 $ 109.3 $ 107.3

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2023
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, 2023 2022 2021 (In millions, except per share data) Net income attributable to WESCO International, Inc. $ 765.5 $ 860.5 $ 465.4 Less: Preferred stock dividends 57.4 57.4 57.4 Net income attributable to common stockholders $ 708.1 $ 803.1 $ 408.0 Weighted-average common shares outstanding used in computing basic earnings per share 51.1 50.7 50.3 Common shares issuable upon exercise of dilutive equity awards 1.2 1.7 1.7 Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share 52.3 52.4 52.0 Earnings per share attributable to common stockholders Basic $ 13.86 $ 15.83 $ 8.11 Diluted $ 13.54 $ 15.33 $ 7.84

EMPLOYEE BENEFIT PLANS - (Table

EMPLOYEE BENEFIT PLANS - (Tables)	12 Months Ended
	Dec. 31, 2023
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 millions) 2023 2022 2023 2022 2023 2022 Change in Projected Benefit Obligation Beginning balance $ 253.5 $ 301.8 $ 267.3 $ 424.1 $ 520.8 $ 725.9 Service cost — — 4.7 8.3 4.7 8.3 Interest cost 10.4 8.7 12.9 9.5 23.3 18.2 Participant contributions — — 1.0 0.9 1.0 0.9 Actuarial (gain) loss, including assumption changes 2.6 (47.1) 29.5 (133.9) 32.1 (181.0) Benefits paid from plan assets (8.1) (9.8) (11.7) (11.1) (19.8) (21.0) Benefits paid from Company assets — — (0.5) (0.5) (0.5) (0.5) Settlement (110.9) — (4.2) (0.2) (115.1) (0.2) Foreign currency exchange rate changes — — 10.1 (29.8) 10.1 (29.8) Ending balance $ 147.5 $ 253.5 $ 309.1 $ 267.3 $ 456.6 $ 520.8 Change in Plan Assets at Fair Value Beginning balance $ 285.1 $ 370.7 $ 267.6 $ 381.8 $ 552.7 $ 752.5 Actual return on plan assets 12.0 (75.8) 24.1 (87.7) 36.1 (163.5) Participant contributions — — 1.0 0.9 1.0 0.9 Employer contributions — — 10.2 11.3 10.2 11.3 Benefits paid (8.1) (9.8) (12.2) (11.1) (20.3) (21.0) Settlement (110.9) — (4.2) (0.2) (115.1) (0.2) Foreign currency exchange rate changes — — 9.2 (27.2) 9.2 (27.2) Ending balance $ 178.1 $ 285.1 $ 295.7 $ 267.6 $ 473.8 $ 552.7 Funded Status $ 30.6 $ 31.6 $ (13.4) $ 0.3 $ 17.2 $ 31.9 Amounts Recognized in the Consolidated Balance Sheets Other assets $ 30.6 $ 31.6 $ 18.0 $ 28.4 $ 48.6 $ 60.0 Other current liabilities — — (0.4) (0.4) (0.4) (0.4) Other noncurrent liabilities — — (31.0) (27.6) (31.0) (27.6) Net amount recognized $ 30.6 $ 31.6 $ (13.4) $ 0.3 $ 17.2 $ 31.9 Weighted Average Assumptions Used to Determine Benefit Obligations Discount rate 4.5 % 4.4 % 4.4 % 4.8 % 4.4 % 4.6 % Rate of compensation increase — % — % 3.3 % 3.4 % 3.3 % 3.4 %
Schedule of Net Benefit Costs [Table Text Block]	The following tables set forth the components of net periodic pension cost (benefit) for the Company's defined benefit plans: Domestic Plans Foreign Plans Total (In millions) 2023 2022 2021 2023 2022 2021 2023 2022 2021 Components of Net Periodic Pension Cost (Benefit) Service cost $ — $ — $ 3.0 $ 4.7 $ 8.3 $ 12.1 $ 4.7 $ 8.3 $ 15.2 Interest cost 10.4 8.7 8.2 12.9 9.5 9.8 23.3 18.2 18.0 Expected return on plan assets (9.6) (14.4) (17.1) (14.0) (17.6) (17.8) (23.6) (32.0) (34.9) Recognized actuarial (loss) gain — — — (2.3) (0.9) 0.1 (2.3) (0.9) 0.1 Curtailment — — (3.9) — — (32.7) — — (36.6) Settlement 4.7 — 0.3 (1.9) (0.1) (0.1) 2.8 (0.1) 0.2 Net periodic pension cost (benefit) $ 5.5 $ (5.7) $ (9.5) $ (0.6) $ (0.8) $ (28.5) $ 4.9 $ (6.5) $ (38.0)
Defined Benefit Plan, Assumptions [Table Text Block]	The following weighted-average actuarial assumptions were used to determine net periodic pension cost (benefit): Domestic Plans Foreign Plans Total 2023 2022 2021 2023 2022 2021 2023 2022 2021 Discount rate 4.4 % 2.9 % 2.6 % 4.8 % 2.4 % 2.0 % 4.6 % 2.6 % 2.3 % Expected return on plan assets 4.8 % 4.3 % 5.3 % 5.5 % 5.0 % 4.9 % 5.1 % 4.6 % 5.1 % Rate of compensation increase — % — % 3.8 % 3.4 % 3.4 % 3.2 % 3.4 % 3.4 % 3.4 %
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 millions) 2023 2022 Changes to Balance: Beginning balance, before tax effect $ (40.6) $ (58.8) Net actuarial loss arising in current year 19.6 14.5 Recognized actuarial loss 2.3 0.9 Settlement (2.8) 0.1 Foreign currency exchange rate changes (1.0) 2.6 Ending balance, before tax effect $ (22.5) $ (40.6) As of December 31, (In millions) 2023 2022 Components of Balance: Prior service credit $ (0.2) $ (0.2) Net actuarial gain (22.3) (40.5) Ending balance, before tax effect (22.5) (40.6) Tax effect 2.8 10.2 Ending balance, after tax effect $ (19.7) $ (30.4)
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 millions) Domestic Plans Foreign Plans Total 2024 $ 148.6 $ 10.5 $ 159.1 2025 — 10.5 10.5 2026 — 11.5 11.5 2027 — 11.9 11.9 2028 — 15.7 15.7 2029 to 2033 — 94.3 94.3
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, 2023 Min Target Max Equities 4.0 % — % 4 % 35 % Debt securities: Domestic treasuries 17.3 — 17 — Corporate bonds 40.5 — 41 — Total debt securities 57.8 58 Cash equivalents 38.2 — 38 — 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2023 Min Target Max Equities 19.7 % 12 % 21 % 29 % Debt securities: Domestic treasuries 0.8 — 1 — Corporate bonds 3.2 1 1 31 Pooled investment funds and other 63.7 48 67 78 Total debt securities 67.7 69 Property/real estate 4.0 2 2 8 Insurance products 7.1 7 7 7 Other 1.5 — 1 8 100.0 % 100 % Domestic Plans Allocation Guidelines December 31, 2022 Min Target Max Equities 2.1 % — % 2 % 35 % Debt securities: Domestic treasuries 5.5 — 5 — Corporate bonds 22.4 — 22 — Other 7.6 — 8 35 Total debt securities 35.5 35 Property/real estate 13.5 — 14 35 Cash equivalents 48.9 — 49 — 100.0 % 100 % Foreign Plans Allocation Guidelines December 31, 2022 Min Target Max Equities 27.3 % 19 % 30 % 38 % Debt securities: Domestic treasuries 0.2 — — — Corporate bonds 4.0 1 1 29 Pooled investment funds and other 52.6 36 54 67 Total debt securities 56.8 55 Property/real estate 4.0 2 4 7 Insurance products 6.9 7 7 7 Other 5.0 4 4 11 100.0 % 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, 2023 (In millions) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 7.2 $ 7.2 Debt securities: Domestic treasuries — — — 30.9 30.9 Corporate bonds — — — 72.0 72.0 Cash equivalents 68.0 — — — 68.0 Total investments in Domestic Plans $ 68.0 $ — $ — $ 110.1 $ 178.1 Foreign Plans Equities $ — $ — $ — $ 58.3 $ 58.3 Debt securities: Domestic treasuries — — — 2.4 2.4 Corporate bonds — — — 9.6 9.6 Pooled investment funds and other — — — 188.2 188.2 Property/real estate — — — 11.8 11.8 Insurance products — 20.9 — — 20.9 Other 4.5 — — — 4.5 Total investments in Foreign Plans $ 4.5 $ 20.9 $ — $ 270.3 $ 295.7 Total Equities $ — $ — $ — $ 65.5 $ 65.5 Debt securities: Domestic treasuries — — — 33.3 33.3 Corporate bonds — — — 81.6 81.6 Pooled investment funds and other — — — 188.2 188.2 Property/real estate — — — 11.8 11.8 Insurance products — 20.9 — — 20.9 Cash equivalents 68.0 — — — 68.0 Other 4.5 — — — 4.5 Total investments $ 72.5 $ 20.9 $ — $ 380.4 $ 473.8 (1) Investments measured at fair value using the net asset value ( “ 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, 2022 (In millions) Level 1 Level 2 Level 3 NAV (1) Total Domestic Plans Equities $ — $ — $ — $ 5.9 $ 5.9 Debt securities: Domestic treasuries — — — 15.6 15.6 Corporate bonds — — — 63.8 63.8 Other — — — 21.7 21.7 Property/real estate — — — 38.7 38.7 Cash equivalents 139.4 — — — 139.4 Total investments in Domestic Plans $ 139.4 $ — $ — $ 145.7 $ 285.1 Foreign Plans Equities $ — $ — $ — $ 73.1 $ 73.1 Debt securities: Domestic treasuries — — — 0.4 0.4 Corporate bonds — — — 10.7 10.7 Pooled investment funds and other — — — 141.0 141.0 Property/real estate — — — 10.6 10.6 Insurance products — 18.5 — — 18.5 Other 3.7 — — 9.6 13.3 Total investments in Foreign Plans $ 3.7 $ 18.5 $ — $ 245.4 $ 267.6 Total Equities $ — $ — $ — $ 79.0 $ 79.0 Debt securities: Domestic treasuries — — — 16.0 16.0 Corporate bonds — — — 74.6 74.6 Pooled investment funds and other — — — 162.7 162.7 Property/real estate — — — 49.3 49.3 Insurance products — 18.5 — — 18.5 Cash equivalents 139.4 — — — 139.4 Other 3.7 — — 9.6 13.3 Total investments $ 143.1 $ 18.5 $ — $ 391.1 $ 552.7 (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, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The fair values of stock options and stock-settled stock appreciation rights, as disclosed in the table above, were estimated using the following weighted-average assumptions in the respective periods: Year Ended December 31, 2023 2022 2021 Risk free interest rate 4.1% 2.0% 0.8% Expected life (in years) 5 7 7 Expected volatility 50% 43% 41% Expected dividend yield 0.89% n/a n/a
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	The following table sets forth a summary of restricted stock units and related information for the periods presented: Year Ended December 31, 2023 2022 2021 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 774,233 $ 73.79 974,162 $ 53.48 921,495 $ 43.15 Granted 177,659 169.65 234,800 122.13 314,480 77.81 Vested (508,173) 59.72 (393,194) 53.13 (232,152) 44.10 Forfeited (36,106) 137.28 (41,535) 66.30 (29,661) 63.86 Unvested at end of year 407,613 $ 127.49 774,233 $ 73.79 974,162 $ 53.48 The following table sets forth a summary of performance-based awards and related information for the periods presented: Year Ended December 31, 2023 2022 2021 Awards Weighted-Average Awards Weighted-Average Awards Weighted-Average Unvested at beginning of year 335,329 $ 75.26 380,819 $ 59.23 305,269 $ 52.61 Granted (1) 212,656 87.04 83,991 122.09 122,812 76.76 Vested (289,394) 48.32 (115,394) 54.64 (22,371) 62.80 Forfeited (3,732) 111.00 (14,087) 60.75 (24,891) 61.26 Unvested at end of year 254,859 $ 115.15 335,329 $ 75.26 380,819 $ 59.23 (1) Includes 63,098 performance-based awards granted in February 2023 with a fair value of $171.96 and three-year performance period ending December 31, 2025, and 144,697 of additional performance-based awards related to awards originally granted in February 2020 with a fair value of $48.32 and three-year performance period ended December 31, 2022 for which actual achievement levels were certified in February 2023. Also includes 3,074, 662, and 549 performance-based awards granted during the three months ended June 30, 2023, September 30, 2023, and December 31, 2023, respectively, with weighted-average fair values of $150.32, $115.04, and $115.21, respectively, and three-year performance periods ending December 31, 2025.
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	During the years ended December 31, 2023, 2022 and 2021, Wesco granted the following stock options, stock-settled stock appreciation rights, restricted stock units, and performance-based awards at the following weighted-average fair values: Year Ended December 31, 2023 2022 2021 Stock options granted 78,729 92,799 — Weighted-average fair value $ 76.69 $ 57.15 n/a Stock-settled stock appreciation rights granted — — 139,592 Weighted-average fair value n/a n/a $ 33.19 Restricted stock units granted 177,659 234,800 314,480 Weighted-average fair value $ 169.65 $ 122.13 $ 77.81 Performance-based awards granted (1) 212,656 83,991 122,812 Weighted-average fair value (1) $ 87.04 $ 122.09 $ 76.76
Share-Based Payment Arrangement, Stock Appreciation Right, 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, 2023 2022 2021 Awards Weighted-Average Weighted-Average Aggregate Awards Weighted-Average Awards Weighted-Average Beginning of year 1,248,115 $ 62.02 1,370,388 $ 62.09 2,161,556 $ 60.48 Granted — — — — 139,592 77.05 Exercised (428,500) 66.70 (113,382) 61.90 (916,906) 60.70 Forfeited (1,331) 74.57 (8,891) 73.35 (13,854) 54.42 End of year 818,284 59.55 5.0 $ 93.6 1,248,115 62.02 1,370,388 62.09 Exercisable at end of year 777,479 $ 58.64 4.9 $ 89.6 1,083,320 $ 61.91 1,001,708 $ 62.79 For the year ended December 31, 2023, the aggregate intrinsic value of stock-settled appreciation rights exercised during such period was $40.2 million.
Share-Based Payment Arrangement, Option, Activity	The following table sets forth a summary of stock options and related information for the periods presented: Year Ended December 31, 2023 2022 Awards Weighted-Average Weighted-Average Remaining Contractual Life (In years) Aggregate Awards Weighted-Average Beginning of year 87,347 $ 121.55 — $ — Granted 78,729 169.72 92,799 121.58 Exercised (1,279) 122.09 — — Forfeited (1,715) 148.67 (5,452) 122.09 End of year 163,082 144.51 8.6 $ 4.8 87,347 121.55 Exercisable at end of year 28,411 $ 121.53 8.1 $ 1.5 879 $ 122.09

BUSINESS SEGMENTS (Tables)

BUSINESS SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables set forth financial information by reportable segment for the periods presented: (In millions) Year Ended December 31, 2023 EES CSS UBS Total Net sales $ 8,610.3 $ 7,152.2 $ 6,622.7 $ 22,385.2 Year Ended December 31, 2022 (In millions) EES CSS UBS Total Net sales $ 8,823.3 $ 6,401.5 $ 6,195.3 $ 21,420.1 Year Ended December 31, 2021 (In millions) EES CSS UBS Total Net sales $ 7,621.3 $ 5,715.2 $ 4,881.0 $ 18,217.5 (In millions) Year Ended December 31, 2023 EES CSS UBS Adjusted EBITDA $ 727.4 $ 683.8 $ 739.3 Adjusted EBITDA margin % 8.4 % 9.6 % 11.2 % Year Ended December 31, 2022 (In millions) EES CSS UBS Adjusted EBITDA $ 851.3 $ 599.0 $ 677.3 Adjusted EBITDA margin % 9.6 % 9.4 % 10.9 % Year Ended December 31, 2021 (In millions) EES CSS UBS Adjusted EBITDA $ 604.5 $ 480.8 $ 428.4 Adjusted EBITDA margin % 7.9 % 8.4 % 8.8 %

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Tables)	12 Months Ended
	Dec. 31, 2022
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 millions) Year Ended December 31, 2023 $ 46.5 $ 18.6 $ — $ (9.2) $ 55.9 Year Ended December 31, 2022 41.7 18.0 — (13.2) 46.5 Year Ended December 31, 2021 23.9 12.9 13.7 (8.8) 41.7 (1) For the year ended December 31, 2021, 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 Deductions (1) end of period Allowance for deferred tax assets (In millions) Year Ended December 31, 2023 $ 33.7 $ 7.7 $ — $ (17.9) $ 23.5 Year Ended December 31, 2022 46.3 5.8 — (18.4) 33.7 Year Ended December 31, 2021 60.6 1.1 1.8 (17.3) 46.3 (1) For the year ended December 31, 2023, deductions primarily relate to a decrease in the valuation allowance recorded against deferred tax assets related to certain foreign jurisdictions. For the years ended December 31, 2022 and 2021, deductions primarily relate to a decrease in the valuation allowance recorded against deferred tax assets related to foreign tax credit carryforwards.

Accounting Policies (Details)

Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) branches	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Nontrade Receivables	$ 233.1	$ 246.2
Accounts Receivable, Allowance for Credit Loss, Current	55.9	46.5
Accounts Receivable, Credit Loss Expense (Reversal)	18.6	18	$ 12.9
Inventory Valuation Reserves	113.4	70
Inventory Write-down	63.1	43.2	$ 37.1
Intangible Assets, Net (Including Goodwill)	4,100	4,000
Self Insurance Reserve	$ 28.1	$ 28
Supplier volume rebate income percentage	1.40%	1.60%	1.40%
Number of Locations | branches	800
Property, buildings and equipment, net	$ 423.6	$ 402.7
Finite-Lived Intangible Assets, Amortization Expense	88.6	92.9	$ 119.6
Supplier Finance Program, Obligation	32.6	30.7
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization	195.4	104.1
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, Accumulated Amortization	$ 15.5	$ 6.1
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]	Accounts payable	Accounts payable
Restricted Cash	$ 21.9	$ 21.2
Leasehold Improvements
Property, Plant, and Equipment, Additional Disclosures	five to forty years
Furniture and Fixtures [Member]
Property, Plant, and Equipment, Additional Disclosures	three to eight years
Software and Software Development Costs [Member]
Property, Plant, and Equipment, Additional Disclosures	three to seven years
Land, Buildings and Improvements
Property, buildings and equipment, net	$ 152.8
Minimum
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Maximum
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	20 years

REVENUE (Details)

REVENUE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Net sales	$ 22,385,200	$ 21,420,100	$ 18,217,500
Selling, general and administrative expense	3,256,000	3,044,200	2,791,600
Contract with Customer, Asset, before Allowance for Credit Loss	35,400	27,500
Deferred Revenue, Revenue Recognized	74,000
Deferred Revenue	111,900	99,600
EES
Disaggregation of Revenue [Line Items]
Net sales	8,610,300	8,823,300	7,621,300
CSS
Disaggregation of Revenue [Line Items]
Net sales	7,152,200	6,401,500	5,715,200
UBS
Disaggregation of Revenue [Line Items]
Net sales	6,622,700	6,195,300	4,881,000
UNITED STATES
Disaggregation of Revenue [Line Items]
Net sales	16,609,100	15,857,300	13,157,900
Canada
Disaggregation of Revenue [Line Items]
Net sales	2,968,200	3,021,400	2,747,200
Other International
Disaggregation of Revenue [Line Items]
Net sales	2,807,900	2,541,400	2,312,500
Shipping and Handling [Member]
Disaggregation of Revenue [Line Items]
Selling, general and administrative expense	$ 306,800	$ 302,300	$ 248,300

REVENUE Variable Consideration

REVENUE Variable Consideration (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue, Information Used to Assess Variable Consideration Constraint	427.8 million	417.1 million	360.6 million
Contract with Customer, Refund Liability	$ 41.3	$ 46.5

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Notional Amount	$ 168.4	$ 172.8
Senior Notes [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	2,823.7	2,881.2
Long-term Debt, Fair Value	$ 2,880.3	$ 2,929.5

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - TEXTUALS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-Lived Intangible Assets, Amortization Expense	$ 88.6	$ 92.9	$ 119.6

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF GOODWILL (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Beginning balance January 1	$ 3,240.9	$ 3,208.3
Ending balance December 31	3,262.3	3,240.9
Goodwill, Acquired During Period	0.9	97.4
Goodwill, Foreign Currency Translation Gain (Loss)	20.5	(64.8)
EES
Goodwill [Roll Forward]
Beginning balance January 1	825.5	861
Ending balance December 31	838.1	825.5
Goodwill, Acquired During Period	0	0
Goodwill, Foreign Currency Translation Gain (Loss)	12.6	(35.5)
UBS
Goodwill [Roll Forward]
Beginning balance January 1	1,206.5	1,225.7
Ending balance December 31	1,212.6	1,206.5
Goodwill, Acquired During Period	0	0
Goodwill, Foreign Currency Translation Gain (Loss)	6.1	(19.1)
CSS
Goodwill [Roll Forward]
Beginning balance January 1	1,208.9	1,121.7
Ending balance December 31	1,211.6	1,208.9
Goodwill, Acquired During Period	0.9	97.4
Goodwill, Foreign Currency Translation Gain (Loss)	$ 1.8	$ (10.2)

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF INTANGIBLE ASSETS BY MAJOR CLASS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization	$ (500)	$ (409.4)
Intangible Assets Gross Excluding Goodwill	2,357.6	2,352.8
Intangible Assets, Net (Excluding Goodwill)	1,857.6	1,943.4
Finite-Lived Intangible Assets, Amortization Expense	88.6	92.9	$ 119.6
Trademarks
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	15.5	15.5
Finite-Lived Intangible Assets, Accumulated Amortization	(9.6)	(7.4)
Finite-Lived Intangible Assets, Net	5.9	8.1
Customer relationships
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,519.9	1,516
Finite-Lived Intangible Assets, Accumulated Amortization	(464.4)	(377.6)
Finite-Lived Intangible Assets, Net	1,055.5	1,138.3
Distribution agreements
Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	29.2	29.2
Finite-Lived Intangible Assets, Accumulated Amortization	(26)	(24.4)
Finite-Lived Intangible Assets, Net	3.2	4.8
Trademarks
Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Gross	$ 793	$ 792.1
Minimum
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Minimum | Trademarks
Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
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

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF EXPECTED AMORTIZATION EXPENSE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2021	$ 86.3
2022	83.2
2023	77.8
2024	74.9
2025	73.2
Thereafter	669.2
Finite-Lived Intangible Assets, Amortization Expense	$ 88.6	$ 92.9	$ 119.6

ACQUISITIONS (Details)

ACQUISITIONS (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Nov. 01, 2022
Business Acquisition [Line Items]
Preferred stock, par value	$ 0.01
Rahi Systems
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		Nov. 01, 2022
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 543.9	$ 111.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets			$ 41.1
Rahi Systems | Customer-Related Intangible Assets
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		17 years

SCHEDULE OF CONSIDERATION TRANS

SCHEDULE OF CONSIDERATION TRANSFERRED (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 0	$ 186.8	$ 0
Rahi Systems
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		255.4
Payment to Acquire Business, Fair Value of Cash Consideration		242.9
Payment for Debt Extinguishment or Debt Prepayment Cost		12.6
Business Combination, Consideration Transferred		255.4
Cash Acquired from Acquisition		68.6
Payments to Acquire Businesses, Net of Cash Acquired		186.8
Business Combination, Price of Acquisition, Expected		217
Business Combination, Consideration Transferred, Other		$ 25.9

SCHEDULE OF ASSUMED ASSETS AND

SCHEDULE OF ASSUMED ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Nov. 01, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Goodwill		$ 3,262.3	$ 3,240.9		$ 3,208.3
Rahi Systems
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	$ 68.6			$ 68.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	52.6			52.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	69			49.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	105.8			105.8
Goodwill, Purchase Accounting Adjustments	0.9
Goodwill	98.3			97.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets	47.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets				41.1
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAssets	26.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	441.8			415
wcc:BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable	28
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	86			58
Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation	20.1			20.1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities	17.8			25
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other				56.4
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsLiabilities	26.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	186.4			159.5
BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsNetAssets	0
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	255.4			$ 255.4
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory	19.6
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets	6.4
us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredIncomeTaxes	(7.2)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities	62.5
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities	$ 6.1

ACQUISITIONS AND DISPOSALS - Ca

ACQUISITIONS AND DISPOSALS - Canadian Divestitures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Disposal Group, Revenue				$ 110
Proceeds from Divestiture of Businesses			$ 56
Gain (Loss) on Disposition of Business	$ 0	$ 0	$ (8.9)

ACQUISITIONS AND DISPOSALS- SYL

ACQUISITIONS AND DISPOSALS- SYLVANIA (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 0	$ 186.8	$ 0

ASSET AND LIABILITIES HELD FOR

ASSET AND LIABILITIES HELD FOR SALE (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Revenue	$ 110

PROPERTY, BUILDINGS AND EQUIP_3

PROPERTY, BUILDINGS AND EQUIPMENT - SCHEDULE OF PROPERTY, BUILDINGS AND EQUIPMENT (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ (502.5)	$ (425.8)
Property, buildings and equipment, net	423.6	402.7
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization	195.4	104.1
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	202.6	169.5
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	359.9	304.7
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	292.6	272.6
Depreciable [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	855.1	746.7
Property, buildings and equipment, net	352.6	320.9
Land
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	25	24.6
Construction in progress
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	$ 46	$ 57.1

PROPERTY, BUILDINGS AND EQUIP_4

PROPERTY, BUILDINGS AND EQUIPMENT - PROPERTY, BUILDINGS AND EQUIPMENT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 56.3	$ 47.8	$ 51.4
Capitalized software amortization	36.4	38.3	$ 27.5
Unamortized software cost	78.2	89.2
Property, Plant and Equipment [Line Items]
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization	195.4	104.1
Finance Lease, Right-of-Use Asset, Accumulated Amortization	19.9	17.1
Finance Lease, Right-of-Use Asset, before Accumulated Amortization	51.9	38.8
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, gross	$ 292.6	$ 272.6

LEASES (Details)

LEASES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	6 years
Operating Lease, Weighted Average Discount Rate, Percent	4.30%	4%
Option to Extend Lessee's Operating Lease, Lease Payments	$ 14.1
Lessee, Operating Lease, Lease Not yet Commenced, Payments	$ 45.7
Lessee, Operating Lease, Lease Not yet Commenced, Description	These operating leases, which are not recorded in the Consolidated Balance Sheet as of December 31, 2023, will commence in 2024 with lease terms of 1 to 10 year

LEASES Supplemental balance she

LEASES Supplemental balance sheet information (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	$ 761.2	$ 625.1
Operating Lease, Liability, Noncurrent	641.7	510.4
Operating Lease, Liability	$ 798.4	$ 640
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current

LEASES Lease, Cost (Details)

LEASES Lease, Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 197	$ 175.8	$ 169.9
Short-term Lease, Cost	8.9	4.8	3.6
Variable Lease, Cost	53.2	45.7	49.5
Lease, Cost	$ 259.1	$ 226.4	$ 222.9

LEASES Supplemental Cash Flow I

LEASES Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Oct. 31, 2023	Nov. 01, 2022
Lessee, Lease, Description [Line Items]
Operating Lease, Payments	$ 174.5	$ 171.7	$ 153.6
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 296.9	$ 267.1	$ 157.5
Rahi Systems
Lessee, Lease, Description [Line Items]
Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation				$ 20.1	$ 20.1

LEASES Lessee, Operating Lease,

LEASES Lessee, Operating Lease, Liability, Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 191.2
Lessee, Operating Lease, Liability, Payments, Due Year Two	172.3
Lessee, Operating Lease, Liability, Payments, Due Year Three	146.7
Lessee, Operating Lease, Liability, Payments, Due Year Four	119
Lessee, Operating Lease, Liability, Payments, Due Year Five	87.4
Lessee, Operating Lease, Liability, Payments, Due after Year Five	188.8
Lessee, Operating Lease, Liability, Payments, Due	905.4
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(107)
Operating Lease, Liability	$ 798.4	$ 640

DEBT - SCHEDULE OF DEBT (Detail

DEBT - SCHEDULE OF DEBT (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	$ 5.6
Total debt	5,359	$ 5,467.3
Debt Instrument, Unamortized Premium	0.1	0.3
Debt Issuance Costs, Net	(37.4)	(51.1)
Less current and short-term portion	(8.6)	(70.5)
Total Long-term Debt, Excluding Current Maturities	$ 5,313.1	$ 5,346
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	$ 1	$ 7.1
Accounts receivable securitization facility
Debt Instrument [Line Items]
Long-term debt	1,550	1,535
Revolving credit facility
Debt Instrument [Line Items]
Long-term debt	953	1,023.6
Senior Notes Due 2023
Debt Instrument [Line Items]
Long-term debt		58.6
Senior Notes Due 2025
Debt Instrument [Line Items]
Long-term debt		4.2
A7125 Senior Notes Due 2025
Debt Instrument [Line Items]
Long-term debt	1,500	1,500
A7250 Senior Notes Due 2028
Debt Instrument [Line Items]
Long-term debt	1,319.4	1,318.2
Debt Instrument, Unamortized Discount	$ 5.6	$ 6.8

DEBT (Details)

DEBT (Details) - USD ($)	5 Months Ended	8 Months Ended	9 Months Ended	11 Months Ended	12 Months Ended							20 Months Ended	24 Months Ended
	Aug. 01, 2022	Oct. 30, 2022	Feb. 28, 2022	May 31, 2021	Jun. 14, 2026	Jun. 14, 2025	Jun. 14, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019	Feb. 28, 2022	Jun. 14, 2028	Aug. 02, 2022	Mar. 01, 2022	Jun. 01, 2021	Dec. 14, 2020	Jun. 22, 2020
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate								6.23%
Accounts Receivable from Securitization								$ 1,550,000,000	$ 1,535,000,000
Percentage of principal amount of Senior Notes accelerated under default								0.25
Debt Issuance Costs, Net								(37,400,000)	$ (51,100,000)
Long-term Debt, Gross								$ 5,364,600,000
Foreign Line of Credit [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate								0.85%	4.84%
Long-term debt								$ 1,000,000	$ 7,100,000
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%				1.05%			0.95%
Accounts Receivable Eligible for Securitization								$ 2,146,900,000	2,028,200,000
Line of Credit Facility, Opportunity to Increase Borrowing Capacity				$ 1,400,000,000				1,750,000,000
Debt Instrument, Unused Borrowing Capacity, Amount								1,625,000,000			$ 600,000,000							$ 1,025,000,000
Long-term debt								$ 1,550,000,000	$ 1,535,000,000
Debt Instrument, Interest Rate, Stated Percentage									0.50%
Commitment Fee								0.45%
5.50% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date								Mar. 01, 2023
Long-term debt								$ 0	$ 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]
Debt Instrument, Maturity Date								Dec. 01, 2025
Long-term debt								$ 4,200,000
Debt Instrument, Interest Rate, Stated Percentage								6%
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%
Deferred Finance Costs, Gross								$ 33,100,000
A7125 Senior Notes Due 2025 | Forecast [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed						100%	101.781%
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								$ 1,319,400,000	1,318,200,000
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
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%
Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Maturity Date								Mar. 01, 2027				Jun. 22, 2025
Line of Credit Facility, Opportunity to Increase Borrowing Capacity		$ 650,000,000						$ 450,000,000		$ 400,000,000
Debt Instrument, Unused Borrowing Capacity, Amount								$ 1,725,000,000						$ 1,525,000,000	$ 1,350,000,000		$ 1,200,000,000	$ 1,100,000,000
Debt Instrument, Interest Rate During Period								6.89%
Debt Instrument, Increase, Additional Borrowings								$ 2,997,200,000	3,990,000,000
Debt Instrument, Decrease, Repayments								3,067,500,000	3,557,100,000
Long-term debt								953,000,000	1,023,600,000
Line of Credit Facility, Remaining Borrowing Capacity								736,000,000	$ 664,900,000
Canadian Dollar Sub-Facility Commitment								625,000,000		500,000,000				600,000,000	550,000,000
Limit on dividends								80,000,000		$ 50,000,000
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					Mar. 01, 2025
Debt Instrument, Basis Spread on Variable Rate	1.10%		1.15%
Line of Credit Facility, Opportunity to Increase Borrowing Capacity			$ 1,500,000,000
Debt Instrument, Unused Borrowing Capacity, Amount														$ 1,525,000,000	$ 1,400,000,000	$ 1,300,000,000	$ 1,200,000,000
Debt Instrument, Interest Rate, Stated Percentage									0%
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								$ 10,000,000
Prime Rate [Member] | Minimum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate								0%
Prime Rate [Member] | Maximum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate								0.50%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Minimum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate								1%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate								1.50%

DEBT - SCHEDULE OF MATURITIES O

DEBT - SCHEDULE OF MATURITIES OF LONG-TERM DEBT (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
2021	$ 8.6
2022	3,063.6
2023	6.4
2024	957.3
2025	1,327.2
Thereafter	1.5
Total payments on debt	5,364.6
Debt discount on convertible debentures	(5.6)
Debt and Lease Obligation	$ 5,359	$ 5,467.3

STOCKHOLDERS' EQUITY (Details)

STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	20,000,000				20,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01
Stock Repurchase Program, Authorized Amount	$ 1,000				$ 1,000
Treasury Stock, Value, Acquired, Cost Method					75	$ 11.1
Dividends, Preferred Stock					57.4	57.4	$ 57.4
Payments of Ordinary Dividends, Common Stock					(76.6)	$ 0	$ 0
Common Stock, Dividends, Per Share, Declared	$ 0.375	$ 0.375	$ 0.375	$ 0.375
Dividends, Common Stock	$ (19.1)	$ (19.1)	$ (19.2)	$ (19.2)	$ (76.6)
Treasury Stock, Common [Member]
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired					504,335	87,502
Treasury Stock, Value, Acquired, Cost Method					$ 75	$ 11.1
Common Stock
Class of Stock [Line Items]
Common Stock, Shares Authorized	210,000,000				210,000,000	210,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01	$ 0.01
Common Class B
Class of Stock [Line Items]
Common Stock, Shares Authorized	20,000,000				20,000,000	20,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01	$ 0.01
Series A Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	25,000				25,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01
Preferred Stock, Dividend Payment Rate, Variable					10.325
Preferred Stock, Liquidation Preference Per Share	$ 25,000				$ 25,000
Preferred Stock, Dividend Rate, Percentage					10.625%
Preferred stock, shares issued	21,612				21,612
Depositary Share [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	21,611,534				21,611,534

INCOME TAXES - ADDITIONAL INFOR

INCOME TAXES - ADDITIONAL INFORMATION (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Amortization of intangible assets	$ 564.5	$ 575.4
Deferred Tax Assets, Operating Loss Carryforwards	36.7	32
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	41.1	52.2
Deferred Tax Assets, Valuation Allowance	23.5	33.7
Unrecognized Tax Benefits	121.3	109.3	$ 107.3	$ 68.1
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	40.1	40.6	36.1
Decrease in Unrecognized Tax Benefits is Reasonably Possible	16.5
Interest related to uncertain tax positions	1.1	2.3	$ 0.9
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	8.9	9.6
Undistributed Earnings of Foreign Subsidiaries	2,194.1
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries	119.3
Unrecognized Tax Benefits, Income Tax Penalties Accrued	4.7	4.8
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability	53.8
Deferred Tax Asset, Interest Carryforward	$ 1.9	4.8
Income Tax Examination, Description	On October 22, 2021, one of the Company's Mexican affiliates received a tax assessment from the Mexican tax authorities in the amount of approximately $26.0 million related to its 2012 income tax return. This amount, updated for adjustments required under Mexican law, was approximately $33.0 million as of December 31, 2023. The Company believes the assessment is without merit and has filed an annulment lawsuit in the Mexican Federal Court of Administrative Justice. The Company expects to prevail in this litigation and, accordingly, has not recognized a liability for this assessment in its consolidated financial statements.In July 2022, one of the Company's Canadian affiliates received tax assessments from the Canada Revenue Agency (“CRA”) totaling approximately $11.0 million, including tax and interest, related to its 2012 through 2014 income tax returns. The Company's Canadian affiliate received a related penalty assessment of approximately $2.7 million in May 2023. The Company believes these assessments are without merit and has appealed to the Tax Court of Canada. The Company intends to avail itself of all avenues to appeal, as necessary to overturn the assessments and expects to prevail. Therefore, the Company has not recognized a liability for these assessments in its consolidated financial statements. The CRA continues to audit the 2015 and 2016 tax years of Wesco's Canadian affiliates and has made inquiries into their 2017 through 2019 income tax returns. The Company expects to eventually receive similar assessments for these tax years.
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 2.9	6.1
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Valuation Allowance	1
Deferred Tax Assets, Operating Loss Carryforwards	3	4.4
Deferred Tax Assets, Valuation Allowance	0.5
Deferred Tax Asset, Interest Carryforward	1.9	4.8
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	7.6
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	31.4	27.6
Operating Loss Carryforwards, Valuation Allowance	12.9	16.7
Deferred Tax Assets, Tax Deferred Expense, Other	6.1	10.9
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 41.1	$ 52.2

INCOME TAXES - SCHEDULE OF INCO

INCOME TAXES - SCHEDULE OF INCOME BEFORE INCOME TAX, DOMESTIC AND FOREIGN (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ 739.4	$ 859.4	$ 396.8
Foreign	252.6	277.3	185.1
Income before income taxes	$ 992	$ 1,136.7	$ 581.9

INCOME TAXES - SCHEDULE OF COMP

INCOME TAXES - SCHEDULE OF COMPONENTS OF INCOME TAX EXPENSE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current taxes
Federal	$ 124.8	$ 166.1	$ 107.9
State	34.6	43	30.2
Foreign	74.4	66.7	55.7
Total current	233.8	275.8	193.8
Deferred taxes
Federal	(1)	(7.5)	(62.3)
State	2.7	0.7	(12.3)
Foreign	(9.6)	5.6	(3.7)
Total deferred	(7.9)	(1.2)	(78.3)
Income tax expense	$ 225.9	$ 274.5	$ 115.5

INCOME TAXES - SCHEDULE OF EFFE

INCOME TAXES - SCHEDULE OF EFFECTIVE INCOME TAX RATE RECONCILIATION (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory rate	21%	21%	21%
State taxes, net of federal tax benefit	3%	3.10%	2%
Effective Income Tax Rate Reconciliation, Deduction, Percent	(0.90%)	(1.20%)	(3.20%)
Unrecognized tax benefits	0%	0.30%	2.50%
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent	0%	0.30%	0.60%
Foreign Income Tax Expense (Benefit), Continuing Operations	(0.90%)	(0.90%)	(2.80%)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent	1.40%	1.40%	(1.10%)
Other	(0.80%)	0.20%	0.90%
Effective income tax rate	22.80%	24.20%	19.90%

INCOME TAXES - SCHEDULE OF DEFE

INCOME TAXES - SCHEDULE OF DEFERRED TAX ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets, Net [Abstract]
Accounts receivable	$ 23.3	$ 21
Deferred Tax Assets, Inventory	45.9	23.9
Deferred Tax Assets, Property, Plant and Equipment	0	0
Deferred Tax Assets, Property, Plant and Equipment	201.8	169.3
Deferred Tax Assets, Goodwill and Intangible Assets	0	0
Employee benefits	21.5	36.5
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	11.2	14.1
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Reserves	0	14
Deferred Tax Asset, Interest Carryforward	1.9	4.8
Tax loss carryforwards	36.7	32
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	41.1	52.2
Other	38.3	37.3
Deferred taxes, Assets	398.2	371.4
Deferred Tax Liabilities [Abstract]
Depreciation	41	46.9
Deferred Tax Liabilities, Leasing Arrangements	192	165.2
Amortization of intangible assets	564.5	575.4
Other	10.3	10.5
Deferred Tax Assets, Gross	421.7	405.1
Deferred Tax Assets, Valuation Allowance	(23.5)	(33.7)
Deferred Tax Liabilities, Gross	807.8	797.9
State and Local Jurisdiction [Member]
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset, Interest Carryforward	1.9	4.8
Tax loss carryforwards	3	$ 4.4
Deferred Tax Liabilities [Abstract]
Deferred Tax Assets, Valuation Allowance	$ (0.5)

INCOME TAXES - SCHEDULE OF IN_2

INCOME TAXES - SCHEDULE OF INCOME TAX CONTINGENCIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Additions for tax positions of prior years	$ 6.6	$ 0.9	$ 8.4
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	0.3
Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation		2.6	1.2
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance January 1	109.3	107.3	68.1
Additions based on tax positions related to the current year	29.2	14.4	39.8
Unrecognized Tax Benefits, Increase Resulting from Acquisition	0.9	5.5	0
Reductions for tax positions of prior years	(6.7)	(1.8)	(3.9)
Settlements	(2.5)	0	(0.1)
Lapse in statute of limitations	(15.8)	(14.5)	(3.8)
Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation		2.6	1.2
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	(0.3)
Ending balance December 31	$ 121.3	$ 109.3	$ 107.3

EARNINGS PER SHARE - SCHEDULE O

EARNINGS PER SHARE - SCHEDULE OF EARNINGS PER SHARE, BASIC AND DILUTED (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock	$ 75	$ 11.1	$ 0
Treasury Stock, Common, Shares	22,720,986	22,115,653
Stock Repurchase Program, Authorized Amount	$ 1,000
Preferred Stock Dividends, Income Statement Impact	$ 57.4	$ 57.4	$ 57.4
Weighted average common shares outstanding used in computing basic earnings per share	51,100,000	50,700,000	50,300,000
Common shares issuable upon exercise of dilutive stock options	1,200,000	1,700,000	1,700,000
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share	52,300,000	52,400,000	52,000,000
Earnings Per Share attributable to WESCO International, Inc.
Basic	$ 13.86	$ 15.83	$ 8.11
Diluted	$ 13.54	$ 15.33	$ 7.84
Net Income (Loss) Available to Common Stockholders, Basic	$ 708.1	$ 803.1	$ 408
Net Income attributable to WESCO International, Inc.	$ 765.5	$ 860.5	$ 465.4
Treasury Stock, Common [Member]
Accelerated Share Repurchases [Line Items]
Treasury Stock, Shares, Acquired	504,335	87,502

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Treasury Stock, Common, Shares	22,720,986	22,115,653
Payments for Repurchase of Common Stock	$ 75	$ 11.1	$ 0
Treasury Stock, Value, Acquired, Cost Method	75	11.1
Treasury Stock, Value, Acquired, Cost Method	$ 75	$ 11.1
Stock Appreciation Rights (SARs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share	200,000	100,000	0
Treasury Stock, Common [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Treasury Stock, Shares, Acquired	504,335	87,502
Treasury Stock, Value, Acquired, Cost Method	$ 75	$ 11.1
Treasury Stock, Value, Acquired, Cost Method	$ 75	$ 11.1

EMPLOYEE BENEFIT PLANS TEXTUALS

EMPLOYEE BENEFIT PLANS TEXTUALS (Details) $ in Millions	2 Months Ended	12 Months Ended
	Feb. 16, 2024 USD ($)	Dec. 31, 2023 USD ($) numberOfPlans	Dec. 31, 2022 USD ($) numberOfPlans	Dec. 31, 2021 USD ($)
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, cost recognized		$ 73.4	$ 58.2	$ 54.7
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. Effective January 1, 2013, the EECOL SERP was closed to new participants and existing participants became 100% vested. Participants of the EECOL SERP now contribute 4% of their earnings to the EECOL Plan.Anixter Inc. sponsors the Anixter Inc. Pension Plan, which was closed to entrants first hired or rehired on or after July 1, 2015, and various defined benefit pension plans covering employees of foreign subsidiaries in Canada and Europe (together with the EECOL Plan and the EECOL SERP, the “Foreign Plans”). The majority of the Company's 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		4.40%	4.60%
Defined Benefit Plan, Benefit Obligation		$ 456.6	$ 520.8	725.9
DefinedBenefitPlanNumberOfPlansWithProjectedBenefitObligationsInExcessOfFairValueOfPlanAssets | numberOfPlans		9	7
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation		$ 215	$ 119
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets		183.8	91
Defined Benefit Plan, Plan Assets, Amount		$ 473.8	$ 552.7	752.5
DefinedBenefitPlanNumberOfPlansWithAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssets | numberOfPlans		9	7
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation		$ 208.6	$ 113.7
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets		183.8	91
Service Cost		$ 4.7	8.3	15.2
Defined Benefit Plan Assets Actual Gain Loss		7%
Defined Benefit Plan, Expected Future Benefit Payment, Year One		$ 159.1
Increase (Decrease) in Other Operating Assets		60.6	153.2	56.3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment		0	0	36.6
Settlement		$ (115.1)	(0.2)
WESCO [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		50%
Defined contribution plan, maximum annual contribution per employee, percent		6%
Defined contribution plan, employer discretionary contribution amount				13.1
Anixter Employee Savings Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		50%
Defined contribution plan, maximum annual contribution per employee, percent		5%
WESCO Deferred Compensation Plan
Schedule of Employee Benefit Plans [Line Items]
Deferred Compensation Liability, Classified, Noncurrent			$ 20.3
AnixterDeferred Compensation Plan
Schedule of Employee Benefit Plans [Line Items]
Deferred Compensation Arrangement with Individual, Distribution Paid				42.8
Increase (Decrease) in Other Operating Assets				39.7
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%
Defined contribution plan, maximum annual contribution per employee, percent		5.50%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		25%
Canadian Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		50%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		4%
U.S. Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		100%
Foreign Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.40%	4.80%
Defined Benefit Plan, Benefit Obligation		$ 309.1	$ 267.3	424.1
Defined Benefit Plan, Plan Assets, Amount		295.7	267.6	381.8
Accumulated Benefit Obligation (ABO) at December 31		302.5	253.2
Service Cost		4.7	8.3	12.1
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year		7
Defined Benefit Plan, Expected Future Benefit Payment, Year One		10.5
Settlement		$ (4.2)	$ (0.2)
United States
Schedule of Employee Benefit Plans [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.50%	4.40%
Defined Benefit Plan, Benefit Obligation		$ 147.5	$ 253.5	301.8
Defined Benefit Plan, Plan Assets, Amount		178.1	285.1	370.7
Accumulated Benefit Obligation (ABO) at December 31		147.5	253.5
Service Cost		0	0	3
Defined Benefit Plan, Expected Future Benefit Payment, Year One		148.6
Settlement		$ (110.9)	0
United States | Subsequent Event
Schedule of Employee Benefit Plans [Line Items]
Settlement	$ 138.8
Minimum | WESCO Distribution Canada Defined Contribution plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		3%
Defined Contribution Plan, Employer Matching Contribution greater than 20 years of service, Percent of Employees' Gross Pay		5%
Minimum | Anixter Employee Savings Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution discretionary contribution percentage		2%
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%
Minimum | Canadian Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		3%
Minimum | U.S. Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		3%
Maximum | WESCO Distribution Canada Defined Contribution plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		5%
Defined Contribution Plan, Employer Matching Contribution greater than 20 years of service, Percent of Employees' Gross Pay		7%
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%
Maximum | Canadian Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		5%
Maximum | U.S. Defined Contribution Plan Merger
Schedule of Employee Benefit Plans [Line Items]
Defined contribution plan, employer matching contribution, percent		4%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		50%
Pension Plan [Member]
Schedule of Employee Benefit Plans [Line Items]
Other Nonoperating Gains (Losses)		$ 0.2	$ (14.8)	$ (53.2)
WESCO Deferred Compensation Plan
Schedule of Employee Benefit Plans [Line Items]
Deferred Compensation Liability, Classified, Noncurrent		$ 27.4

EMPLOYEE BENEFIT PLANS Benefit

EMPLOYEE BENEFIT PLANS Benefit Obligations, Plan Assets, and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation	$ 456.6	$ 520.8	$ 725.9
Service Cost	4.7	8.3	15.2
Interest cost	23.3	18.2
Participant contributions	1	0.9
Actuarial (gain) loss	32.1	(181)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(19.8)	(21)
DefinedBenefitPlanBenefitsPaidFromCompanyAssets	(0.5)	(0.5)
Settlement	(115.1)	(0.2)
Foreign Currency Translation Gain (Loss)	10.1	(29.8)
Defined Benefit Plan, Plan Assets, Amount	473.8	552.7	752.5
Actual return on plan assets	36.1	(163.5)
Participant contributi	1	0.9
Company contributions	10.2	11.3
Defined Benefit Plan, Plan Assets, Benefits Paid	(20.3)	(21)
Settlement	(115.1)	(0.2)
Foreign Currency Translation Gain (Loss)	9.2	(27.2)
Funded status	17.2	31.9
Assets for Plan Benefits, Defined Benefit Plan	48.6	60
Current liabilities	(0.4)	(0.4)
Non-current liabilities	$ (31)	$ (27.6)
Discount rate	4.40%	4.60%
Average salary increases	3.30%	3.40%
United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation	$ 147.5	$ 253.5	301.8
Service Cost	0	0	3
Interest cost	10.4	8.7
Participant contributions	0	0
Actuarial (gain) loss	2.6	(47.1)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(8.1)	(9.8)
DefinedBenefitPlanBenefitsPaidFromCompanyAssets	0	0
Settlement	(110.9)	0
Foreign Currency Translation Gain (Loss)	0	0
Defined Benefit Plan, Plan Assets, Amount	178.1	285.1	370.7
Actual return on plan assets	12	(75.8)
Participant contributi	0	0
Company contributions	0	0
Defined Benefit Plan, Plan Assets, Benefits Paid	(8.1)	(9.8)
Settlement	(110.9)	0
Foreign Currency Translation Gain (Loss)	0	0
Funded status	30.6	31.6
Assets for Plan Benefits, Defined Benefit Plan	30.6	31.6
Current liabilities	0	0
Non-current liabilities	$ 0	$ 0
Discount rate	4.50%	4.40%
Average salary increases	0%	0%
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation	$ 309.1	$ 267.3	424.1
Service Cost	4.7	8.3	12.1
Interest cost	12.9	9.5
Participant contributions	1	0.9
Actuarial (gain) loss	29.5	(133.9)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(11.7)	(11.1)
DefinedBenefitPlanBenefitsPaidFromCompanyAssets	(0.5)	(0.5)
Settlement	(4.2)	(0.2)
Foreign Currency Translation Gain (Loss)	10.1	(29.8)
Defined Benefit Plan, Plan Assets, Amount	295.7	267.6	$ 381.8
Actual return on plan assets	24.1	(87.7)
Participant contributi	1	0.9
Company contributions	10.2	11.3
Defined Benefit Plan, Plan Assets, Benefits Paid	(12.2)	(11.1)
Settlement	(4.2)	(0.2)
Foreign Currency Translation Gain (Loss)	9.2	(27.2)
Funded status	(13.4)	0.3
Assets for Plan Benefits, Defined Benefit Plan	18	28.4
Current liabilities	(0.4)	(0.4)
Non-current liabilities	$ (31)	$ (27.6)
Discount rate	4.40%	4.80%
Average salary increases	3.30%	3.40%

EMPLOYEE BENEFIT PLANS Pension

EMPLOYEE BENEFIT PLANS Pension Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure
Service Cost	$ 4.7	$ 8.3	$ 15.2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Total net periodic pension (benefit) cost	$ 4.9	$ (6.5)	$ (38)
United States
Defined Benefit Plan Disclosure
Service Cost	$ 0	$ 0	$ 3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Total net periodic pension (benefit) cost	$ 5.5	$ (5.7)	$ (9.5)
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Service Cost	$ 4.7	$ 8.3	$ 12.1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Total net periodic pension (benefit) cost	$ (0.6)	$ (0.8)	$ (28.5)

EMPLOYEE BENEFIT PLANS Assumpti

EMPLOYEE BENEFIT PLANS Assumptions (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate	4.60%	2.60%	2.30%
Expected Long-term Rate of Return on Plan Assets	5.10%	4.60%	5.10%
Rate of Compensation Increase	3.40%	3.40%	3.40%
Foreign Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate	4.80%	2.40%	2%
Expected Long-term Rate of Return on Plan Assets	5.50%	5%	4.90%
Rate of Compensation Increase	3.40%	3.40%	3.20%
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate	4.40%	2.90%	2.60%
Expected Long-term Rate of Return on Plan Assets	4.80%	4.30%	5.30%
Rate of Compensation Increase	0%	0%	3.80%

EMPLOYEE BENEFIT PLANS - AOCI (

EMPLOYEE BENEFIT PLANS - AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Postemployment Benefits [Abstract]
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	$ (22.5)	$ (40.6)	$ (58.8)
Actuarial (Gain) Loss Arising During Period, before Tax	$ 19.6	$ 14.5
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Settlement	$ (2.8)	$ 0.1
Foreign currency translation Gain Loss	(1)	2.6
Prior Service Cost (Credit), before Tax	(0.2)	(0.2)
Actuarial (Gain) Loss, before Tax	(22.3)	(40.5)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	2.8	10.2
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	$ (19.7)	$ (30.4)

EMPLOYEE BENEFIT PLANS Benefi_2

EMPLOYEE BENEFIT PLANS Benefit payments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One	$ 159.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	10.5
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	11.5
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	11.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	15.7
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	94.3
Defined Benefit Plan, Plan Assets, Payment for Settlement	115.1	$ 0.2
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Payment for Settlement			$ 17.9
United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One	148.6
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	0
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	0
Defined Benefit Plan, Plan Assets, Payment for Settlement	110.9	0
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Expected Future Benefit Payment, Year One	10.5
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	10.5
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	11.5
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	11.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	15.7
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	94.3
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 4.2	$ 0.2

EMPLOYEE BENEFIT PLANS Asset al

EMPLOYEE BENEFIT PLANS Asset allocations (Details)	Dec. 31, 2023	Dec. 31, 2022
United States
Defined Benefit Plan Disclosure
Total investments	100%	100%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100%	100%
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	100%	100%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100%	100%
Defined Benefit Plan, Equity Securities | United States
Defined Benefit Plan Disclosure
Total investments	4%	2.10%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	4%	2%
Defined Benefit Plan, Equity Securities | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
Defined Benefit Plan, Equity Securities | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	35%	35%
Defined Benefit Plan, Equity Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	19.70%	27.30%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	21%	30%
Defined Benefit Plan, Equity Securities | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	12%	19%
Defined Benefit Plan, Equity Securities | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	29%	38%
US Treasury and Government | United States
Defined Benefit Plan Disclosure
Total investments	17.30%	5.50%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	17%	5%
US Treasury and Government | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
US Treasury and Government | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
US Treasury and Government | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	0.80%	0.20%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	0%
US Treasury and Government | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
US Treasury and Government | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
Corporate Debt Securities | United States
Defined Benefit Plan Disclosure
Total investments	40.50%	22.40%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	41%	22%
Corporate Debt Securities | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
Corporate Debt Securities | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
Corporate Debt Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	3.20%	4%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	1%
Corporate Debt Securities | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	1%
Corporate Debt Securities | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	31%	29%
Other Debt Obligations | United States
Defined Benefit Plan Disclosure
Total investments		7.60%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		8%
Other Debt Obligations | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		0%
Other Debt Obligations | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		35%
Other Debt Obligations | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	63.70%	52.60%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	67%	54%
Other Debt Obligations | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	48%	36%
Other Debt Obligations | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	78%	67%
Defined Benefit Plan, Debt Security | United States
Defined Benefit Plan Disclosure
Total investments	57.80%	35.50%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	58%	35%
Defined Benefit Plan, Debt Security | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	67.70%	56.80%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	69%	55%
Real Estate Funds | United States
Defined Benefit Plan Disclosure
Total investments		13.50%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		14%
Real Estate Funds | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		0%
Real Estate Funds | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		35%
Real Estate Funds | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4%	4%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	2%	4%
Real Estate Funds | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	2%	2%
Real Estate Funds | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	8%	7%
Other Investments [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	1.50%	5%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	4%
Other Investments [Member] | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	4%
Other Investments [Member] | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	8%	11%
Insurance product | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	7.10%	6.90%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	7%	7%
Insurance product | Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	7%	7%
Insurance product | Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	7%	7%
Cash Equivalents | United States
Defined Benefit Plan Disclosure
Total investments	38.20%	48.90%
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	38%	49%
Cash Equivalents | United States | Minimum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%
Cash Equivalents | United States | Maximum [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	0%	0%

EMPLOYEE BENEFIT PLANS Fair val

EMPLOYEE BENEFIT PLANS Fair value plan assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 473.8	$ 552.7	$ 752.5
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	100%	100%
Defined Benefit Plan, Plan Assets, Amount	$ 295.7	$ 267.6	381.8
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100%	100%
United States
Defined Benefit Plan Disclosure
Total investments	100%	100%
Defined Benefit Plan, Plan Assets, Amount	$ 178.1	$ 285.1	$ 370.7
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	100%	100%
Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 72.5	$ 143.1
Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	4.5	3.7
Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	68	139.4
Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	20.9	18.5
Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	20.9	18.5
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	380.4	391.1
Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	270.3	245.4
Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	110.1	145.7
Other Investments [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 4.5	$ 13.3
Other Investments [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	1.50%	5%
Defined Benefit Plan, Plan Assets, Amount	$ 4.5	$ 13.3
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	4%
Other Investments [Member] | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 4.5	$ 3.7
Other Investments [Member] | Level 1 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	4.5	3.7
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 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] | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	9.6
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	0	9.6
Defined Benefit Plan, Equity Securities
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 65.5	$ 79
Defined Benefit Plan, Equity Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	19.70%	27.30%
Defined Benefit Plan, Plan Assets, Amount	$ 58.3	$ 73.1
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	21%	30%
Defined Benefit Plan, Equity Securities | United States
Defined Benefit Plan Disclosure
Total investments	4%	2.10%
Defined Benefit Plan, Plan Assets, Amount	$ 7.2	$ 5.9
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	4%	2%
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	65.5	79
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	58.3	73.1
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	7.2	5.9
US Treasury and Government
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 33.3	$ 16
US Treasury and Government | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	0.80%	0.20%
Defined Benefit Plan, Plan Assets, Amount	$ 2.4	$ 0.4
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	0%
US Treasury and Government | United States
Defined Benefit Plan Disclosure
Total investments	17.30%	5.50%
Defined Benefit Plan, Plan Assets, Amount	$ 30.9	$ 15.6
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	17%	5%
US Treasury and Government | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0	$ 0
US Treasury and Government | Level 1 | Foreign Plan [Member]
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 | Foreign Plan [Member]
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 | Foreign Plan [Member]
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	33.3	16
US Treasury and Government | Fair Value Measured at Net Asset Value Per Share | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	2.4	0.4
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	30.9	15.6
Corporate Debt Securities
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 81.6	$ 74.6
Corporate Debt Securities | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	3.20%	4%
Defined Benefit Plan, Plan Assets, Amount	$ 9.6	$ 10.7
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	1%	1%
Corporate Debt Securities | United States
Defined Benefit Plan Disclosure
Total investments	40.50%	22.40%
Defined Benefit Plan, Plan Assets, Amount	$ 72	$ 63.8
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	41%	22%
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	81.6	74.6
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	9.6	10.7
Corporate Debt Securities | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	72	63.8
Other Debt Obligations
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 188.2	$ 162.7
Other Debt Obligations | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	63.70%	52.60%
Defined Benefit Plan, Plan Assets, Amount	$ 188.2	$ 141
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	67%	54%
Other Debt Obligations | United States
Defined Benefit Plan Disclosure
Total investments		7.60%
Defined Benefit Plan, Plan Assets, Amount		$ 21.7
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		8%
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
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
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
Other Debt Obligations | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	188.2	162.7
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	188.2	141
Other Debt Obligations | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount		21.7
Real Estate Funds
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 11.8	$ 49.3
Real Estate Funds | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	4%	4%
Defined Benefit Plan, Plan Assets, Amount	$ 11.8	$ 10.6
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	2%	4%
Real Estate Funds | United States
Defined Benefit Plan Disclosure
Total investments		13.50%
Defined Benefit Plan, Plan Assets, Amount		$ 38.7
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities		14%
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
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
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
Real Estate Funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	11.8	49.3
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	11.8	10.6
Real Estate Funds | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount		38.7
Insurance product
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 20.9	$ 18.5
Insurance product | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Total investments	7.10%	6.90%
Defined Benefit Plan, Plan Assets, Amount	$ 20.9	$ 18.5
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	7%	7%
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	20.9	18.5
Insurance product | Level 2 | Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	20.9	18.5
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	0
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	0
Cash Equivalents
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 68	$ 139.4
Cash Equivalents | United States
Defined Benefit Plan Disclosure
Total investments	38.20%	48.90%
Defined Benefit Plan, Plan Assets, Amount	$ 68	$ 139.4
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	38%	49%
Cash Equivalents | Level 1
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 68	$ 139.4
Cash Equivalents | Level 1 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	68	139.4
Cash Equivalents | Level 2
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	0
Cash Equivalents | Level 2 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	0
Cash Equivalents | Level 3
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	0
Cash Equivalents | Level 3 | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	0
Cash Equivalents | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	0	0
Cash Equivalents | Fair Value Measured at Net Asset Value Per Share | United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Plan Assets, Amount	$ 0	$ 0

EMPLOYEE BENEFIT PLANS - Other

EMPLOYEE BENEFIT PLANS - Other Benefits (Details) - Phantom Share Units (PSUs) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure
Other Deferred Compensation Arrangements, Liability, Classified, Noncurrent		$ 8.1
Share-based Payment Arrangement, Expense	$ 0.1	2.6	$ 13.6
Deferred Compensation Cash-based Arrangements, Liability, Current and Noncurrent		$ 8
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 Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2026	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
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							$ 48.1	$ 46.4	$ 30.8
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value							$ 172.8	68.3	69.7
Common Stock, Capital Shares Reserved for Future Issuance	1,877,701						1,877,701
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 50.2						$ 50.2
Share-based Payment Arrangement, Expense, Tax Benefit							$ 40.8	$ 15.8	$ 16.8
Risk free interest rate							4.10%	2%	0.80%
Expected life (in years)							5 years	7 years	7 years
Expected volatility							50%	43%	41%
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate							0.89%
Share-Based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross							78,729	92,799	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value							$ 76.69	$ 57.15
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value							$ 40.2
Granted							0	0	139,592
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
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	407,613						407,613	774,233	974,162	921,495
Granted							177,659	234,800	314,480
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value							$ 169.65	$ 122.13	$ 77.81
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	254,859						254,859	335,329	380,819	305,269
Granted	549	662	3,074				212,656	83,991	122,812
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 115.21	$ 115.04	$ 150.32				$ 87.04	$ 122.09	$ 76.76
Performance Shares [Member] | 2023 Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted							63,098
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value							$ 171.96
Performance Shares [Member] | 2020 Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted							144,697
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value							$ 48.32
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%
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%
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%
Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense							$ 48.1	$ 46.4	$ 30.8
Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 1.9	$ 16.1	$ 32.2

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 Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
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				$ 66.70	$ 61.90	$ 60.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	28,411			28,411	879
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	254,859			254,859	335,329	380,819	305,269
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 115.21	$ 115.04	$ 150.32	$ 87.04	$ 122.09	$ 76.76
Share Based Compensation Arrangements By Share Based Payment Award, Options and Stock Appreciation Rights Outstanding [Roll Forward]
Stock-settled appreciation rights granted	549	662	3,074	212,656	83,991	122,812
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
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				428,500	113,382	916,906
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures				1,331	8,891	13,854
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price				$ 74.57	$ 73.35	$ 54.42
Weighted Average Remaining Contractual Term, Outstanding				5 years
Weighted Average Remaining Contractual Term, Exercisable				4 years 10 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 93.6			$ 93.6
Aggregate Intrinsic Value, Exercisable	$ 89.6			$ 89.6
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	777,479			777,479	1,083,320	1,001,708
Stock-settled appreciation rights granted				0	0	139,592
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 58.64			$ 58.64	$ 61.91	$ 62.79
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 59.55			$ 59.55	$ 62.02	$ 62.09	$ 60.48
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	818,284			818,284	1,248,115	1,370,388	2,161,556
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price				$ 0	$ 0	$ 77.05
Share-Based Payment Arrangement, Option
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				122.09	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price				$ 148.67	122.09
Weighted Average Remaining Contractual Term, Exercisable				8 years 1 month 6 days
Aggregate Intrinsic Value, Exercisable	$ 1.5			$ 1.5
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price	$ 121.53			$ 121.53	122.09
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 144.51			144.51	121.55	$ 0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price				$ 169.72	$ 121.58
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number	163,082			163,082	87,347	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross				78,729	92,799	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period				(1,279)	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period				(1,715)	(5,452)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term				8 years 7 months 6 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value	$ 4.8			$ 4.8

STOCK-BASED COMPENSATION - SUMM

STOCK-BASED COMPENSATION - SUMMARY OF RESTRICTED STOCK UNITS AND PERFORMANCE-BASED AWARDS (Details) - $ / shares	3 Months Ended			12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Shares	254,859			254,859	335,329	380,819	305,269
Granted	549	662	3,074	212,656	83,991	122,812
Vested in Period				(289,394)	(115,394)	(22,371)
Unvested, Weighted Average Fair Value	$ 115.15			$ 115.15	$ 75.26	$ 59.23	$ 52.61
Granted, Weighted Average Fair Value	$ 115.21	$ 115.04	$ 150.32	87.04	122.09	76.76
Vested in Period, Weighted Average Fair Value				$ 48.32	$ 54.64	$ 62.80
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(3,732)	(14,087)	(24,891)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value				$ 111	$ 60.75	$ 61.26
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Shares	407,613			407,613	774,233	974,162	921,495
Granted				177,659	234,800	314,480
Vested in Period				(508,173)	(393,194)	(232,152)
Unvested, Weighted Average Fair Value	$ 127.49			$ 127.49	$ 73.79	$ 53.48	$ 43.15
Granted, Weighted Average Fair Value				169.65	122.13	77.81
Vested in Period, Weighted Average Fair Value				$ 59.72	$ 53.13	$ 44.10
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(36,106)	(41,535)	(29,661)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value				$ 137.28	$ 66.30	$ 63.86

STOCK-BASED COMPENSATION - SC_2

STOCK-BASED COMPENSATION - SCHEDULE OF SHARE-BASED PAYMENT AWARDS, VALUATION ASSUMPTIONS (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	4.10%	2%	0.80%
Expected life (in years)	5 years	7 years	7 years
Expected volatility	50%	43%	41%
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-settled appreciation rights granted	0	0	139,592

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, 2023 Rate	Dec. 31, 2022 Rate	Dec. 31, 2021 Rate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
WESCO expected volatility	50%	43%	41%
Risk-free interest rate	4.10%	2%	0.80%

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Letters of Credit Outstanding, Amount	$ 60.9

BUSINESS SEGMENTS (Details)

BUSINESS SEGMENTS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Employees countries segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting [Abstract]
Net sales	$ 22,385,200	$ 21,420,100	$ 18,217,500
Operating Income (Loss)	1,406,400	1,438,100	801,900
Segment Reporting Information [Line Items]
Net sales	22,385,200	21,420,100	18,217,500
Operating Income (Loss)	1,406,400	1,438,100	801,900
Adjusted EBITDA	$ 1,705,300	$ 1,725,600	$ 1,175,700
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other, net	Other, net	Other, net
Depreciation and amortization	$ 181,300	$ 179,000	$ 198,600
Other, net	25,100	7,000	(48,100)
Capitalized software amortization	36,400	38,300	27,500
Stock-based compensation expense (EBITDA)	45,500	41,000	25,700
Stock-based compensation expense	48,100	46,400	30,800
Business Combination, Integration Related Costs	55,400	67,400	158,500
Gain (Loss) on Disposition of Assets			(8,900)
Gain (Loss) on Disposition of Business	0	0	(8,900)
Payments for (Proceeds from) Productive Assets	92,300	99,400	54,700
Net Income (Loss) Available to Common Stockholders, Basic	708,100	803,100	408,000
Net loss attributable to noncontrolling interest	600	1,700	1,000
Preferred Stock Dividends, Income Statement Impact	57,400	57,400	57,400
Income Tax Expense (Benefit)	225,900	274,500	115,500
Interest expense, net	389,300	294,400	268,100
Restructuring Costs	16,700
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 15,060,900	14,811,700
Number of Reportable Segments | segment	3
EES
Segment Reporting [Abstract]
Net sales	$ 8,610,300	8,823,300	7,621,300
Segment Reporting Information [Line Items]
Net sales	8,610,300	8,823,300	7,621,300
Adjusted EBITDA	$ 727,400	$ 851,300	$ 604,500
Adjusted EBITDA Margin Percentage	8.40%	9.60%	7.90%
Depreciation and amortization	$ 43,300	$ 42,600	$ 56,000
Other, net	(10,100)	2,000	1,900
Stock-based compensation expense (EBITDA)	5,800	9,200	6,400
Business Combination, Integration Related Costs	0	0	0
Gain (Loss) on Disposition of Assets			0
Payments for (Proceeds from) Productive Assets	10,300	9,100	4,500
Net Income (Loss) Available to Common Stockholders, Basic	668,700	801,300	543,600
Net loss attributable to noncontrolling interest	(500)	200	300
Preferred Stock Dividends, Income Statement Impact	0	0	0
Income Tax Expense (Benefit)	$ 0	0	0
Entity Number of Employees | Employees	6,800
Additional countries (in countries) | countries	50
Interest expense, net	$ 0	0	0
Restructuring Costs	0
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,553,600	4,480,300
CSS
Segment Reporting [Abstract]
Net sales	7,152,200	6,401,500	5,715,200
Segment Reporting Information [Line Items]
Net sales	7,152,200	6,401,500	5,715,200
Adjusted EBITDA	$ 683,800	$ 599,000	$ 480,800
Adjusted EBITDA Margin Percentage	9.60%	9.40%	8.40%
Depreciation and amortization	$ 71,700	$ 68,400	$ 82,900
Other, net	(74,200)	1,300	(1,300)
Stock-based compensation expense (EBITDA)	5,200	4,900	2,600
Business Combination, Integration Related Costs	0	0	0
Gain (Loss) on Disposition of Assets			0
Payments for (Proceeds from) Productive Assets	7,900	4,800	3,200
Net Income (Loss) Available to Common Stockholders, Basic	531,100	527,000	394,000
Net loss attributable to noncontrolling interest	1,600	0	0
Preferred Stock Dividends, Income Statement Impact	0	0	0
Income Tax Expense (Benefit)	$ 0	0	0
Entity Number of Employees | Employees	4,400
Additional countries (in countries) | countries	50
Interest expense, net	$ 0	0	0
Restructuring Costs	0
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	5,626,600	5,504,000
UBS
Segment Reporting [Abstract]
Net sales	6,622,700	6,195,300	4,881,000
Segment Reporting Information [Line Items]
Net sales	6,622,700	6,195,300	4,881,000
Adjusted EBITDA	$ 739,300	$ 677,300	$ 428,400
Adjusted EBITDA Margin Percentage	11.20%	10.90%	8.80%
Depreciation and amortization	$ 25,000	$ 23,300	$ 22,400
Other, net	1,400	(2,000)	0
Stock-based compensation expense (EBITDA)	3,200	3,500	2,100
Business Combination, Integration Related Costs	0	0	0
Gain (Loss) on Disposition of Assets			(8,900)
Payments for (Proceeds from) Productive Assets	19,500	9,200	5,200
Net Income (Loss) Available to Common Stockholders, Basic	712,500	648,500	412,700
Net loss attributable to noncontrolling interest	0	0	0
Preferred Stock Dividends, Income Statement Impact	0	0	0
Income Tax Expense (Benefit)	$ 0	0	0
Entity Number of Employees | Employees	2,900
Interest expense, net	$ 0	0	0
Restructuring Costs	0
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,908,500	3,827,400
Corporate Segment
Segment Reporting Information [Line Items]
Adjusted EBITDA	(445,200)	(401,900)	(338,000)
Merger-related Stock-based compensation expense	2,600	5,400	5,100
Depreciation and amortization	41,300	44,700	37,200
Other, net	57,800	(8,300)	47,600
Stock-based compensation expense (EBITDA)	31,300	23,400	14,600
Business Combination, Integration Related Costs	55,400	67,400	158,500
Gain (Loss) on Disposition of Assets			0
Payments for (Proceeds from) Productive Assets	54,600	76,400	41,900
Net Income (Loss) Available to Common Stockholders, Basic	(1,204,200)	(1,173,700)	(942,400)
Net loss attributable to noncontrolling interest	(500)	1,500	700
Preferred Stock Dividends, Income Statement Impact	57,400	57,400	57,400
Income Tax Expense (Benefit)	225,900	274,500	115,500
Interest expense, net	(389,300)	(294,400)	$ (268,100)
Restructuring Costs	16,700
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 972,200	$ 999,900

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	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 1,184,800	$ 1,027,800
Net sales	22,385,200	21,420,100	$ 18,217,500
Depreciation and amortization	181,300	179,000	198,600
Payments for (Proceeds from) Productive Assets	92,300	99,400	54,700
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	906,500	790,100
Net sales	16,609,100	15,857,300	13,157,900
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	182,100	167,000
Net sales	2,968,200	3,021,400	2,747,200
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	96,200	70,700
Net sales	$ 2,807,900	$ 2,541,400	$ 2,312,500

Schedule II - Valuation and Q_3

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
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	$ 55.9	$ 46.5	$ 41.7	$ 23.9
Valuation Allowances and Reserves, Charged to Cost and Expense	18.6	18	12.9
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	13.7
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	(9.2)	(13.2)	(8.8)
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	23.5	33.7	46.3	$ 60.6
Valuation Allowances and Reserves, Charged to Cost and Expense	7.7	5.8	1.1
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	1.8
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	$ (17.9)	$ (18.4)	$ (17.3)