Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue Disaggregation
Revenue	$ 4,247.2	$ 3,847.4	$ 13,414.2	$ 10,104.6
Carbon steel
Revenue Disaggregation
Revenue	2,371.9	2,406.4	7,545.2	6,163.7
Stainless steel
Revenue Disaggregation
Revenue	712.7	621.3	2,284.7	1,613.7
Aluminum
Revenue Disaggregation
Revenue	660.3	534.9	2,069.9	1,496.5
Alloy
Revenue Disaggregation
Revenue	188.2	143.8	568.5	396.0
Toll processing and logistics
Revenue Disaggregation
Revenue	139.5	119.7	414.8	350.9
Copper and brass
Revenue Disaggregation
Revenue	81.0	18.1	260.4	49.6
Other and eliminations
Revenue Disaggregation
Revenue	$ 93.6	$ 3.2	$ 270.7	$ 34.2