Condensed Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Condensed Consolidated Statements Of Comprehensive Income [Abstract]
Net Income	$ 80.3	$ 37.1	$ 127.6	$ 58.6
Other Comprehensive Income
Foreign currency translation	2.0	4.1	3.5	(5.1)
Pension and postretirement benefits liability adjustments (net of tax of $(2.2), $(2.0), $(4.5) and $(3.9), respectively)	6.2	5.7	12.8	11.2
Total Other Comprehensive Income	8.2	9.8	16.3	6.1
Comprehensive Income	88.5	46.9	143.9	64.7
Less: Comprehensive income attributable to noncontrolling interests, net of tax	0.2	0.2	0.4
Comprehensive Income attributable to Graybar Electric Company, Inc.	$ 88.3	$ 46.7	$ 143.5	$ 64.7