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Inventories (Tables) | 3 Months Ended
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Mar. 31, 2018
Inventory Disclosure [Abstract] |
Schedule of Inventories | Inventories at March 31, 2018 and December 31, 2017 were as follows (in millions):
| March 31, 2018 |  | December 31, 2017
Raw materials and supplies | $ | 175.7 |  |  | $ | 162.8 |
Work-in-process | 931.8 |  |  | 955.5 |
Finished goods | 181.2 |  |  | 165.0 |
Total inventories at current cost | 1,288.7 |  |  | 1,283.3 |
Adjustment from current cost to LIFO cost basis | 23.1 |  |  | 43.1 |
Inventory valuation reserves | (101.0 | ) |  | (121.5 | )
Progress payments | — |  |  | (28.8 | )
Total inventories, net | $ | 1,210.8 |  |  | $ | 1,176.1 |
Schedule of Inventory Valuation Impact on Income | Impacts to cost of sales for changes in the LIFO costing methodology and associated NRV inventory reserves were as follows (in millions):
|  | Three months ended March 31,
|  | 2018 |  | 2017
LIFO benefit (charge) |  | $ | (8.2 | ) |  | $ | (8.1 | )
NRV benefit (charge) |  | 8.2 |  |  | 8.1 |
Net cost of sales impact |  | $ | — |  |  | $ | — |

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