| Schedule of property, plant and equipment along with respective useful lives |
| | | | | | | | | | | | | | December 31, | | Useful Lives | | 2019 | | 2018 | | | | ($ in millions) | Land and improvements to land | 10-20 Years | | $ | 277.5 |
| | $ | 276.9 |
| Buildings and building equipment | 10-30 Years | | 392.4 |
| | 387.6 |
| Machinery and equipment | 3-20 Years | | 5,566.0 |
| | 5,252.0 |
| Leasehold improvements | | | 9.9 |
| | 5.2 |
| Construction in progress | | | 346.1 |
| | 341.4 |
| Property, plant and equipment | | | 6,591.9 |
| | 6,263.1 |
| Accumulated depreciation | | | (3,268.1 | ) | | (2,781.0 | ) | Property, plant and equipment, net | | | $ | 3,323.8 |
| | $ | 3,482.1 |
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