Condensed Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Condensed Consolidated Statements Of Comprehensive Income [Abstract]
Net Income	$ 74.5	$ 34.6	$ 202.1	$ 93.2
Other Comprehensive Income
Foreign currency translation	(3.4)	2.2	0.1	(2.9)
Pension and postretirement benefits liability adjustments (net of tax of $(11.6), $(3.0), $(16.1) and $(6.9), respectively)	33.7	8.6	46.5	19.8
Total Other Comprehensive Income	30.3	10.8	46.6	16.9
Comprehensive Income	104.8	45.4	248.7	110.1
Less: Comprehensive income attributable to noncontrolling interests, net of tax	0.1	0.2	0.5	0.2
Comprehensive Income attributable to Graybar Electric Company, Inc.	$ 104.7	$ 45.2	$ 248.2	$ 109.9