Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenue Disaggregation
Revenue	$ 3,643.3	$ 3,880.3	$ 7,288.1	$ 7,845.6
Carbon steel
Revenue Disaggregation
Revenue	2,025.7	2,141.2	4,038.6	4,269.7
Aluminum
Revenue Disaggregation
Revenue	587.8	639.7	1,183.9	1,309.9
Stainless steel
Revenue Disaggregation
Revenue	521.8	604.0	1,081.7	1,261.3
Alloy
Revenue Disaggregation
Revenue	166.8	186.8	338.7	378.2
Toll processing and logistics
Revenue Disaggregation
Revenue	161.2	154.5	319.0	309.9
Copper and brass
Revenue Disaggregation
Revenue	87.0	77.9	162.3	159.9
Other and eliminations
Revenue Disaggregation
Revenue	$ 93.0	$ 76.2	$ 163.9	$ 156.7