Letter of credit fees, percentage.

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- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

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- Definition

Private Placement Issuance Period

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No definition available.

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- Definition

Amount of short-term and long-term debt and lease obligation.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Amount of interest income (expense) classified as operating.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

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- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

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- Definition

Date the credit facility terminates, in YYYY-MM-DD format.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Debt (Narrative) (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
Debt (Narrative) (Details) - USD ($)	Jun. 27, 2025	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023
Line of Credit Facility [Line Items]
Total debt		$ 2,000,000.0		$ 2,000,000.0		$ 2,200,000
Long-term debt		1,000,000.0		1,000,000.0		1,300,000
Short-term borrowings		0		0		22,000,000.0
Remaining borrowing capacity						724,200,000
Interest income (expense), net		100,000	$ (500,000)	400,000	$ (1,000,000.0)
Letters of credit outstanding		9,800,000		9,800,000		$ 9,600,000
Minimum [Member]
Line of Credit Facility [Line Items]
Short-term borrowings		0	0	0	0
Maximum [Member]
Line of Credit Facility [Line Items]
Short-term borrowings		37,000,000.0	$ 38,000,000.0	37,000,000.0	$ 38,000,000.0
Credit Agreement [Member]
Line of Credit Facility [Line Items]
Debt instrument, term						5 years
Maximum borrowing capacity						$ 750,000,000.0
Expiration date						Aug. 01, 2026
Accordion feature, increase limit						$ 375,000,000.0
Credit Agreement [Member] \| Graybar Canada [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						100,000,000.0
Credit Agreement [Member] \| Letter of Credit Sub Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						25,000,000.0
Credit Agreement [Member] \| Swing-Line Loan [Member] \| United States [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						75,000,000.0
Credit Agreement [Member] \| Swing-Line Loan [Member] \| Canada [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						20,000,000.0
Amended Credit Agreement [Member]
Line of Credit Facility [Line Items]
Debt instrument, term	5 years
Accordion feature, increase limit	$ 375,000,000.0
Debt maturity date	Jun. 01, 2030
Remaining borrowing capacity		745,900,000		$ 745,900,000
Credit agreement commitment fee percentage				0.40%
Amended Credit Agreement [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Credit agreement commitment fee percentage	0.25%
Amended Credit Agreement [Member] \| Minimum [Member] \| Base Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Amended Credit Agreement [Member] \| Minimum [Member] \| Other Rates [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Amended Credit Agreement [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Credit agreement commitment fee percentage	0.40%
Amended Credit Agreement [Member] \| Maximum [Member] \| Base Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.60%
Amended Credit Agreement [Member] \| Maximum [Member] \| Other Rates [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.60%
Amended Credit Agreement [Member] \| Graybar Canada [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 100,000,000.0
Letters of credit outstanding		4,100,000		$ 4,100,000		3,800,000
Amended Credit Agreement [Member] \| Letter of Credit Sub Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 35,000,000.0
Amended Credit Agreement [Member] \| Letter of Credit Sub Facility [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Letter of credit fees, percentage	1.00%
Amended Credit Agreement [Member] \| Letter of Credit Sub Facility [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Letter of credit fees, percentage	1.60%
Amended Credit Agreement [Member] \| Swing-Line Loan [Member] \| United States [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 75,000,000.0
Amended Credit Agreement [Member] \| Swing-Line Loan [Member] \| Canada [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 20,000,000.0
Prudential Private Placement Shelf Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity		200,000,000.0		$ 200,000,000.0
Issuance period				3 years
Notes issued face amount		0		$ 0		$ 0
MetLife Private Placement Shelf Agreement [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 200,000,000.0		$ 200,000,000.0
Notes issued face amount							$ 0	$ 0