Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
GrossRevenues	$ 1,990.8	$ 1,878.9	$ 5,734.0	$ 5,364.3
SalesDiscounts	9.4	8.7	26.8	24.1
Revenues	1,981.4	1,870.2	5,707.2	5,340.2
Cost of merchandise sold	(1,603.6)	(1,516.8)	(4,623.0)	(4,324.2)
Gross Margin	377.8	353.4	1,084.2	1,016.0
Selling, general and administrative expenses	(293.0)	(276.4)	(851.0)	(810.5)
Depreciation and amortization	(12.6)	(12.6)	(37.7)	(37.0)
Other income, net	0.6	1.0	2.4	2.4
Income from Operations	72.8	65.4	197.9	170.9
Non-operating expenses	(5.9)	(7.8)	(18.8)	(22.8)
Income before Provision for Income Taxes	66.9	57.6	179.1	148.1
Provision for income taxes	(17.9)	(4.0)	(48.7)	(28.7)
Net Income	49.0	53.6	130.4	119.4
Less: Net income attributable to noncontrolling interests	(0.2)	(0.1)	(0.3)	(0.3)
Net Income attributable to Graybar Electric Company, Inc.	$ 48.8	$ 53.5	$ 130.1	$ 119.1
Net Income per share of Common Stock (in dollars per share)	$ 2.28	$ 2.50	$ 6.05	$ 5.55
Cash Dividends per share of Common Stock (in dollars per share)	$ 0.30	$ 0.30	$ 0.90	$ 0.90
Average Common Shares Outstanding (Shares)	21.5	21.4	21.5	21.4