Debt	12 Months Ended
	Dec. 31, 2021
Debt [Abstract]
Debt	12. DEBT December 31,Long-term Debt 2021 2020Finance arrangements, various maturities, with a weighted average interest rate of 7.8%$ 6.1 $ 8.0Less current portion (1.9) (2.3)Long-term Debt$ 4.2 $ 5.7 Long-term Debt matures as follows: 2022$ 1.9 2023 1.3 2024 1.2 2025 0.9 2026 0.2 After 2026 0.6 $ 6.1 The carrying amount of our outstanding long-term, fixed-rate debt exceeded its fair value by $0.9 million and $1.3 million at December 31, 2021 and 2020, respectively.  The fair value of the long-term, fixed-rate debt is estimated by calculating future cash flows at interpolated Treasury yields with similar maturities, plus an estimate of our credit risk spread.  The fair value of our variable-rate short- and long-term debt approximates its carrying value at December 31, 2021 and 2020, respectively. Revolving Credit Facility At December 31, 2020, we, along with Graybar Canada Limited, our Canadian operating subsidiary (“Graybar Canada”), had an unsecured, five-year, $750.0 million committed revolving credit agreement maturing in August 2023 with Bank of America, N.A. and the other lenders named therein (the “Revolving Credit Facility”), which included a combined letter of credit sub-facility of up to $25.0 million, a U.S. swing-line loan facility of up to $75.0 million, and a Canadian swing-line loan facility of up to $20.0 million.  The Revolving Credit Facility included a $100.0 million sublimit (in U.S. or Canadian dollars) for borrowings by Graybar Canada.  The Revolving Credit Facility contained an accordion feature, which allowed us to request increases in the aggregate borrowing commitments of up to $375.0 million. On August 13, 2021, we, along with Graybar Canada, amended and extended the Revolving Credit Facility, pursuant to the terms and conditions of a Fourth Amendment to Credit Agreement, dated as of August 13, 2021 (the “Amended Credit Agreement”), by and among Graybar, as parent borrower and guarantor, Graybar Canada Limited, as a borrower, the lenders party thereto, Bank of America, N.A. as Domestic Administrative Agent, Domestic Swing Line Lender and Domestic L/C Issuer and Bank of America, N.A., acting through its Canada Branch, as Canadian Administrative Agent, Canadian Swing Line Lender and Canadian L/C Issuer, which includes a combined letter of credit sub-facility of up to $25.0 million, a U.S. swing-line loan facility of up to $75.0 million, and a Canadian swing-line loan facility of up to $20.0 million. The Amended Credit Agreement also includes a $100.0 million sublimit (in U.S. or Canadian dollars) available for borrowings by Graybar Canada. Our borrowing availability under the facility is reduced by the amount of borrowings by Graybar Canada, but we may use the sublimit amount to increase our borrowings, to the extent available. If we were to use available borrowings under the Amended Credit Agreement that included the sublimit amount, then Graybar Canada’s available capacity would be reduced by our use of such amount. The Amended Credit Agreement contains an accordion feature, which allows us to request increases in the aggregate borrowing commitments of up to $375.0 million. Interest on our borrowings under the Revolving Credit Facility will be based on, at the borrower’s election, either (A) (i) the base rate (as defined in the agreement) or (ii) LIBOR (in the case U.S. dollar-denominated borrowings) or (B) (i) the base rate (as defined in the agreement) or (ii) CDOR (in the case of Graybar Canada as borrower with respect to Canadian dollar-denominated borrowings), in each case plus an applicable margin, as determined by the pricing grid set forth in the Amended Credit Agreement. The Amended Credit Agreement added LIBOR fallback language to address the announced future cessation of specified dollar LIBOR tenor settings.  In connection with such a borrowing, the applicable borrower will also select the term of the loan from available tenors, up to six months, or automatically renew with the consent of the lenders.  Swing line loans, which are daily loans, will bear interest at a rate based on, at the borrower’s election, either (i) the base rate or (ii) the daily floating Eurodollar rate (or CDOR, in the case of Graybar Canada with respect to Canadian dollar-denominated borrowings).  In addition to interest payments, there are certain fees and obligations associated with borrowings, swing-line loans, letters of credit and other administrative matters. The five-year Amended Credit Agreement matures in August 2026. Borrowings of Graybar Canada may be in U.S. dollars or Canadian dollars.  The obligations of Graybar Canada are secured by the guaranty of Graybar and any material domestic subsidiaries of Graybar (as defined).  Under no circumstances will Graybar Canada use its borrowings to benefit Graybar or its operations, including without limitation to repay any of Graybar’s obligations under the facility. The Amended Credit Agreement provides for a quarterly commitment fee ranging from 0.25% to 0.40% per annum, subject to adjustment based upon the consolidated leverage ratio for a fiscal quarter, and letter of credit fees ranging from 1.00% to 1.60% per annum payable quarterly, subject to such adjustment.  Borrowings can be either base rate loans plus a margin ranging from 0.00% to 0.60%, or LIBOR loans plus a margin ranging from 1.00% to 1.60%, both subject to adjustment based upon the consolidated leverage ratio, or an alternative benchmark rate. Availability under the Amended Credit Agreement is subject to the accuracy of representations and warranties and absence of a default and, in the case of Canadian borrowings denominated in Canadian dollars, the absence of a material adverse change in the national or international financial markets, which would make it impracticable to lend Canadian dollars. The Amended Credit Agreement contains updated customary affirmative and negative covenants for credit facilities of this type, including limitations on us and all but certain of our subsidiaries with respect to indebtedness (with specified, limited exceptions), liens, changes in the nature of our business, investments, mergers and acquisitions, issuance of equity securities, dispositions of assets and dissolution of certain subsidiaries, transactions with affiliates, as well as securitizations, factoring transactions, and transactions with sanctioned parties or in violation of certain US or Canadian anti-corruption and anti-money laundering laws.  There are also maximum leverage ratio and minimum interest coverage ratio financial covenants to which we will be subject during the term of the Amended Credit Agreement. The Amended Credit Agreement also provides for customary events of default, including a failure to pay principal, interest or fees when due, failure to comply with covenants, the fact that any representation or warranty made by any of the credit parties is materially incorrect, the occurrence of an event of default under certain other indebtedness by us and our subsidiaries, the commencement of certain insolvency or receivership events affecting any of the credit parties, certain actions under the Employee Retirement Income Security Act of 1974 ("ERISA") and the occurrence of a change in control of any of the credit parties (subject to certain permitted transactions as described in the Amended Credit Agreement).  Upon the occurrence of an event of default, the commitments of the lenders may be terminated and all outstanding obligations of the credit parties under the Amended Credit Agreement may be declared immediately due and payable. We were in compliance with all covenants under the Amended Credit Agreement and Revolving Credit Facility as of December 31, 2021 and 2020, respectively. There were $124.2 million and $50.0 million in short-term borrowings under the Amended Credit Agreement and the Revolving Credit Facility, respectively, as of December 31, 2021 and 2020. Short-term borrowings outstanding during the year ended December 31, 2021 ranged from a minimum of no short-term borrowings to a maximum of $124.2 million. Short-term borrowings outstanding during the year ended December 31, 2020 ranged from a minimum of $50.0 million to a maximum of $370.0 million.  The average daily amount of borrowings outstanding under the Amended Credit Agreement and Revolving Credit Facility during 2021 and 2020 amounted to approximately $10.6 million and $191.6 million at weighted-average interest rates 1.15% and 1.55%, respectively.  The weighted-average interest rate for amounts outstanding at December 31, 2021 was 1.11%. At December 31, 2021, we had available unused committed lines of credit under the Amended Credit Agreement amounting to $625.4 million, compared to $699.6 million at December 31, 2020 under the Revolving Credit Facility. Interest expense, net was $1.0 million, $3.6 million, and $5.5 million for the years ended December 31, 2021, 2020, and 2019, respectively. Private Placement Shelf Agreements We have an uncommitted, unsecured $100.0 million private placement shelf agreement (the "Prudential Shelf Agreement") with PGIM, Inc., which is expected to allow us to issue senior promissory notes to affiliates of PGIM, Inc. at fixed rate terms to be agreed upon at the time of any issuance during a three-year issuance period ending in August 2023. We also have an uncommitted, unsecured $150.0 million private placement shelf agreement (the "MetLife Shelf Agreement") with MetLife Investment Management, LLC (formerly known as MetLife Investment Advisors, LLC), and MetLife Investment Management Limited (collectively, “MetLife”) and each other MetLife affiliate that becomes a party to the agreement. After its amendment and extension in June 2021, the MetLife Shelf Agreement is expected to allow us to issue senior promissory notes to MetLife at fixed or floating rate economic terms to be agreed upon at the time of issuance during a three-year period ending in June 2024. On August 13, 2021, we amended each of these uncommitted private placement shelf agreements to conform to specified changes in the Amended Credit Agreement. We remain obligated under a most favored lender clause which is designed to ensure that any notes in the future under the Prudential Shelf Agreement and MetLife Shelf Agreement will continue to be of equal ranking with indebtedness under our Amended Credit Agreement. No notes have been issued under either the Prudential Shelf Agreement or the MetLife Shelf Agreement as of December 31, 2021 and 2020. Each shelf agreement contains representations and warranties of the Company and the applicable lender, events of default and affirmative and negative covenants, customary for agreements of this type.  After the amendment and extension of the Amended Credit Agreement and related amendments to the Prudential Shelf Agreement and MetLife Shelf Agreement, these covenants are substantially similar to those contained in the Amended Credit Agreement, subject to a number of exceptions and qualifications set forth in the applicable shelf agreement. All outstanding obligations of Graybar under one or both of these agreements may be declared immediately due and payable upon the occurrence of an event of default. We were in compliance with all covenants under the Prudential Shelf Agreement and the MetLife Shelf Agreements as of December 31, 2021 and 2020. Letters of Credit We had total letters of credit of $6.1 million outstanding at December 31, 2021, of which $0.4 million were issued under the Amended Credit Agreement. We had total letters of credit of $6.3 million outstanding at December 31, 2020, of which $0.4 million were issued under the Revolving Credit Facility. The letters of credit are issued primarily to support certain workers' compensation insurance policies.