|**Inventories**                     | 12 Months Ended                                                                                                                                                                                                                                                                       
|----------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Inventory Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                       
|Inventories                         | InventoriesThe following table presents the components of the Company’s inventory balances:December 31 (dollars in millions)20212020Finished products$190.2$143.4Work in process42.021.8Raw materials286.3159.2Inventories, at FIFO cost518.5324.4LIFO reserve(70.8)(24.3)$447.7$300.1
|                                    |                                                                                                                                                                                                                                                                                       
|December 31 (dollars in millions)   | 2021                                                                                                                                                                                                                                                                                  
|Finished products                   | $                                                                                                                                                                                                                                                                                     
|Work in process                     | 42.0                                                                                                                                                                                                                                                                                  
|Raw materials                       | 286.3                                                                                                                                                                                                                                                                                 
|Inventories, at FIFO cost           | 518.5                                                                                                                                                                                                                                                                                 
|LIFO reserve                        | (70.8)                                                                                                                                                                                                                                                                                
|                                    | $                                                                                                                                                                                                                                                                                     

X- ReferencesNo definition available.
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+ ReferencesReference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -URI http://asc.fasb.org/topic&trid=2126998
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