Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenue Disaggregation
Revenues	$ 3,659.8	$ 3,643.3	$ 7,144.5	$ 7,288.1
Carbon steel
Revenue Disaggregation
Revenues	2,044.2	2,025.7	3,948.4	4,038.6
Aluminum
Revenue Disaggregation
Revenues	619.9	587.8	1,225.5	1,183.9
Stainless steel
Revenue Disaggregation
Revenues	489.2	521.8	992.4	1,081.7
Alloy
Revenue Disaggregation
Revenues	167.5	166.8	325.9	338.7
Toll processing and logistics
Revenue Disaggregation
Revenues	164.3	161.2	324.5	319.0
Copper and brass
Revenue Disaggregation
Revenues	98.9	87.0	180.6	162.3
Miscellaneous and eliminations
Revenue Disaggregation
Revenues	$ 75.8	$ 93.0	$ 147.2	$ 163.9